1. Garlic (Allium sativum L.) Classification
Kingdom: Plantae (Plants)
Subkingdom: Tracheobionta (Vascular Plants)
Superdivision: Spermatophyta (Seed Plants)
Division: Magnoliophyta (Flowering Plants)
Class: Liliopsida (Monocotyledons)
Liliaceae Adans., Fam. Pl. 2: 42. Jul-Aug 1763.
Amaryllidaceae J. St.-Hil., Expos. Fam. Nat. 1: 134. Feb-Apr 1805.
Alliaceae J. Agardh, Theoria Syst. Pl.: 32. Apr-Sep 1858.
Note: Some authorities place the onions, garlic, leeks and their relatives in a family of their own, the Alliaceae; some others place them altogether within the amaryllis family, the Amaryllidaceae, and others put them in the lily family, the Liliaceae. There is no consensus.
Genus: Allium L.
Species: Allium sativum L.
- Allium controversum Schrad.
- Allium sativum var. controversum (Schrad.) Regel
- Allium sativum var. ophioscorodon (Link) Doll
There exist several dozens varieties of Allium sativum L. “garlic”. Sometimes they are grouped into two groups: ‘softneck’ and ‘hardneck’. Softneck varieties are more common. Hardneck garlic (a.k.a. rocambole, top-setting garlic, and serpent garlic) is Allium sativum var. ophioscorodon (Link) Doll. It produces a flower stalk that coils like a snake, then straightens out and bears clusters of pea-sized bulblets or "bulbils" that are like miniature garlic bulbs.
There are about 400 species in the genus Allium, including some magnificent ornamentals. Some members of the genus include:
- Allium acuminatum
- Allium acutiflorum
- Allium akaka
- Allium albopilosum
- Allium altaicum
- Allium altissimum
- Allium amabile
- Allium ampeloprasum “wild leek”
- Allium angulare
- Allium angulosum
- Allium ascalonicum “shallot”
- Allium atropurpureum
- Allium beesianum
- Allium bisceptrum
- Allium bodeanum
- Allium bolanderi
- Allium brevistylum
- Allium caeruleum
- Allium canadense“wild American garlic”
- Allium carinatum
- Allium carolinianum
- Allium cepa “onion”
- Allium cernuum
- Allium chamaemoly
- Allium chinense
- Allium christophii
- Allium cupanii
- Allium cyaneum
- Allium dichylamydeum
- Allium douglasii
- Allium dregeanum
- Allium drummondii
- Allium fistulosum “bunching onion”, “green onion”
- Allium flavum “yellow garlic”
- Allium galanthum
- Allium geyeri
- Allium giganteum
- Allium grayi
- Allium grosii
- Allium hollandicum
- Allium hookeri
- Allium insubricum
- Allium jesdianum
- Allium karataviense
- Allium kunthii
- Allium kurrat
- Allium ledebourianum
- Allium longicuspis Regel
- Allium macleanii
- Allium macropetalum
- Allium macrostemon
- Allium melananthum
- Allium moly
- Allium monanthum
- Allium moschatum
- Allium mutabile
- Allium narcissflorum
- Allium neapolitanum “white garlic”
- Allium nectaroscordum
- Allium nigrum “black garlic”
- Allium obliquum
- Allium oleraceum
- Allium oleraceum “wild British garlic”
- Allium oreophilum
- Allium orientale
- Allium oschaninii
- Allium ostrowskianum
- Allium paniculatum
- Allium paradoxum
- Allium pendulinum
- Allium platycaule
- Allium porrum “leek”
- Allium przewalskianum
- Allium pyrenaicum
- Allium ramosum
- Allium roseum “pink garlic”
- Allium rotundum
- Allium rubellum
- Allium rubrum
- Allium ruhmerianum
- Allium sacculiferum
- Allium schoenoprasum “chive”,“French chive”
- Allium schubertii
- Allium scorodoprasum “black garlic”
- Allium semenovii
- Allium senescens
- Allium sphaerocephalon
- Allium splendens
- Allium stellatum
- Allium stipitatum
- Allium stracheyi
- Allium suaveolens
- Allium subhirsutum
- Allium taquetii
- Allium textile
- Allium thunbergii
- Allium tricoccum
- Allium triquetrum “Tears of the Virgin”
- Allium tuberosum “garlic chives”
- Allium unifolium
- Allium ursinum “bear’s garlic”
- Allium validum
- Allium victorialis “victorial garlic”
- Allium vineale
- Allium vineale
- Allium wallichii
- Allium zebdanense
- Nothoscordum bivalve “false North American garlic”
A plant botanically not related but containing similar aroma compounds (and thus showing a similar fragrance) is asafetida (Ferula assa-foetida).
Common Names: “garlic”, “allium”, “cropleek”, “cultivated garlic”, “softneck garlic”, “hardneck garlic”, “poor man’s treacle”, “rocambole”, “serpent garlic”, “stinking rose”, “rashona”, “Russian penicillin”. Albanian: “Hudhër e rëndomtë”. Amharic: “Netch Shinkurt”. Arabic: ثوم , فوم , ثُوم , فُوم , “Fum”, “Thoum”, “Thum”. Armenian: “Skhdor”, “Sxtor”. Assamese: “Naharu”. Azeri: “Sarımsaq” “Сарымсаг”. Basque: “Baratzuri”, “Barahatz”, “Baratxuri”, “Berakatz”. Bengali: “Rasun”. Bulgarian: Чеснов лук, Чесън “Chesnov luk”, “Chesun”. Burmese: “Chyet-thon-phew”, “Kesumphiu”. Catalan: “All”. Chinese: “Suen tau”, “Suan”, “hsiao suan”, “lai”, “lasan”, “da suan”. Croatian: “Češnjak”, “Bijeli luk”. Czech: “Česnek”. Danish: “Hvidløg”. Dutch: “Knoflook”. Esperanto: “Ajlo”. Estonian: “Küüslauk”. Fante: “Sara anwiw”. Farsi: سیر “Sir”, “Cire”. Finnish: “Valkosipuli”. French: “Ail”, “Thériaque des pauvres”, “ail de cuisine”. Frisian: “Knyflok”. Ga-Dangme: “Samanatsopa”, “Aya”, “Ayo”. Gaelic: “Garleag”. Galician: “Allo”. Georgian: “Niori”. German: “Knoblauch”. Greek: “Σκόρδο”, “Skordo”. Gujarati: “Lasan”. Hausa: “Tafarnuwa”, “Tafaranoa”. Hebrew: “שום ”, “Shum”. Hindi: “Lasun”. Hungarian: “Fokhagyma”. Icelandic: “Hvítlaukur”. Indonesian: “Bawang putih”, “Kesuna”. Italian: “Aglio”. Japanese: “Ninniku”, “Garikku”. Kannada: “Bellulli”, “Lashuna”, “Ulli”. Kazakh: “Сарымса”, “Sarımsaq”. Laotian: “Van mahakan”, “Phak thiem”. Latvian: “Ķiploki”. Lithuanian: “Česnakas”. Malay: “Bawang putih”. Malayalam: “Veluthulli”. Maltese: “Tewm”. Marathi: “Lasun”. Norwegian: “Hvitløk”. Oriya: “Rasuna”. Papiamento: “Konofló”, “Konoflok”. Pashto: “Seer”. Polish: “Czosnek pospolity”. Portuguese: “Alho”. Provençal: “Aiet”, “Aïo”. Romanian: “Usturoi”. Russian: Чеснок (Chesnok). Sanskrit: “Lashuna”. Singhalese: “Sudulunu”. Slovak: “Cesnak kuchynský”. Slovenian: “Česen”. Spanish: “ajo”. Sranan: “Kunofroku”. Swahili: “Kitunguu saumu”. Swedish: “Vitlök”. Tagalog: “Bawang”. Tamil: “Vellai pundu”, “Vellai poondu”. Telugu: “Tellagadda”, “Vellulli”. Thai: “Katiem”, “Gratiem”. Tibetan: “Gogpa”, “Sgog pa”. Twi: “Gyene kankan”. Turkish: “Sarmısak”. Ukrainian: Часник (Chasnyk), Часник городній (Chasnyk horodni). Urdu: “Lehsun”. Vietnamese: “Toi”. Yiddish: “Knobl”. Others: “bawang poetih”, “bawang puteh”, “rosina”, “samersaq”, “sarimsak”, “sir”, “suan”, “thum”.
2. Garlic Description
2.1 Habit: Perennial herb. Most varieties stand about 0.3 m to 0.6 m tall at maturity, although some varieties can reach up to 1.5 m in height.
Allium sativum L. “garlic” plants produce an underground bulb that usually is divisible into pieces. This bulb, commonly known as head, is ovoid; the odor and flavor are intense and characteristic. The bulb is covered by a papyraceous envelope, white, pink, or purple, and is made of several pieces (6 to 20 segments) or bulblets easily separable known technically as cloves. The cloves are grouped together between the membranous scales and enclosed within a whitish skin, which holds them as in a sac.
From the bulb emerge both the photosynthetic leaves and the inflorescence. The main stem of Allium sativum L. “garlic” is very short and underground. There exist some varieties with gigantic and miniature bulbs. The latter one is cultivated in Southeast Asia, and is constituted by 4 to 6 cloves per bulb.
2.2 Leaves: The leaves are long (up to 30 cm long), narrow (up to 8 mm wide) and flat (not hollow) like grass and emerge directly from the very short main stem, which is underground. They present a crease down the middle and are held erect in two opposite ranks. At the base, they are fused at their margins forming tunicae as in the bulb of Allium cepa L. “onion”.
In Allium sativum L. “garlic”, however, the leaves emerging from the main stem and forming the bulb are not fleshy but thin and papyraceous when dry. At the axils of these tunicae a series of buds are produced (from 1 to 5 at each axil) known as collateral buds, each one of which transform in a short bulb (the ‘clove’).
Each clove is constituted by an outer leave, which is tunicate and thin, a second tunicate leave but thick and fleshy, and a little bud that will shoot the next season (the green part we can see at the middle of each clove).
The leaves are tunicate at their bases, forming a sheath, and are sessile, ribbon-shaped, and with parallel margins. Their section is V-shaped and the main vein is pretty prominent on the abaxial face.
2.3 Flowers: As all the species within the genus Allium, the flowers are arranged on an umbeliform cyma located at the apex of a fistulous stem placed at the end of a stalk rising direct from the bulb, up to 0.5 m tall, without leaves. The inflorescence is surrounded and covered by a very long protective leave (spathe) that separates and withers during flowering.
The flowers are not very abundant (sometimes lacking); most of them are sterile or have become tiny bulbils, very similar to those forming the cloves in the bulb and are distributed among the other flowers. The flowers are hermaphrodite (have both male and female organs), short, whitish or greenish, sometimes pink-colored, trimerous, with six stamens, and tricarpelar ginoecium. They are pollinated by bees and insects and later abscise.
The common names Rocambole and Serpent garlic are applied to varieties of Allium sativum L. having coiled or twisted scapes, the flower stalks.
2.4 Fruit: Capsule. The seeds are black and reniform (kidney-shaped).
3. Garlic Origin, Distribution and Ecology
3.1 Origin: Allium sativum L. “garlic” is a cultigen that has been cultivated for more than 5 000 years. Domestication of Allium sativum L. seems to be taken place in Central Asia, although there does not exist Allium sativum L. “garlic” specimens on the wild today. The wild species from which Allium sativum L. “garlic” evolved is unknown. Its most closely related relative seems to be Allium longicuspis Regel, native to Central Asia.
Of the about 700 species of genus Allium, many stem from Central Asia, the center of diversity ranging from the Himalayas to Turkestan.
De Candolle, in his treatise on the Origin of Cultivated Plants, considered that it was apparently indigenous to the southwest of Siberia, whence it spread to southern Europe, where it has become naturalized, and is said to be found wild in Sicily.
3.2 Distribution: Although it is thought to be native to Eurasia, today, Allium sativum L. is cultivated worldwide. In Britain, it is an occasional garden escape.
It is widely cultivated in the Latin countries bordering on the Mediterranean. Dumas has described the air of Provence as being 'particularly perfumed by the refined essence of this mystically attractive bulb.'
3.3 Ecology: Allium sativum L. “garlic” is grown as an annual, started from cloves broken out of the bulb. The original habitat (wild situation) of Allium sativum L. is obscure. This plant species is only known in cultivation.
Allium sativum L. “garlic” is very efficient to uptake and sequester sulfur from the soil. The acquisition of sulfur and its distribution to various metabolic pathways may have been an important survival mechanism for the alliums; grazing animals maybe learned to avoid the alliums because of their strong taste. Production of Allium sativum L. “garlic” in a low sulfur environment reduces the pungency of it.
· Propagation: Allium sativum L. “garlic” is a cultigen. This means that this plant species is only found cultivated; there exist no wild specimens. It implies that Allium sativum L. “garlic” cannot propagate by itself; this plant species depends strictly on humans in order to be perpetuated. It almost never produces fertile seeds.
Plants are usually produced by planting a clove, or a bulblet that forms in the flower head. Being cultivated since time immemorial in order to benefit from its bulbs, Allium sativum L. “garlic” has lost its ability to propagate sexually. Instead, this plant species has been selected by humans in order to be propagated asexually.
The bulbs should be planted fairly deeply. They have to be planted flattened end down, about 5 cm to 7.6 cm deep and 7.6 cm to 10 cm apart. Rocambole can be started from cloves or from the little bulblets that are produced on the top of the looping stem, but the cloves grow faster.
· Climate: Allium sativum L. “garlic” is best planted in the fall and summer. All commercial planting in the U.S. is in areas of mid winter climate, mainly in California. Cloves are best planted in the fall (October to January), and allowed to overwinter in the ground to be harvested the following mid to late summer.
In the western United States, Allium sativum L. “garlic” is planted in the spring or from autumn to mid-winter. In mild climates Allium sativum L. “garlic” will grow all winter; in cold climates areas, it will go dormant in the winter, and should be mulched. In the South, plantings are made in fall. It tolerates at least -10° C.
· Soil: Allium sativum L. succeeds in most soils but prefers light (sandy) and medium (loamy) or clayey soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils but dislikes very acid soils, although can grow in very alkaline soils. It tolerates a pH in the range 4.5 to 8.3. It requires dry or moist soil. Bulb development is below the soil surface so that he bulb is liable to rot if grown in a wet soil.
· Bulb formation: Bulb formation occurs in response to increasing daylength and temperature. It is also influenced by the temperature at which the cloves were stored prior to planting. Cool storage at temperatures between 0º C and 10° C will hasten subsequent bulb formation; storage at above 25° C will delay or prevent bulb formation.
The underground bulbs are harvested when the leaves wither. Traditionally, early emerging Allium sativum L. “garlic” has cloves that are enclosed in white scales of the parent bulb while late Allium sativum L. “garlic” has cloves that are enclosed in pinkish scales of the parent bulb.
Artificial drying of harvested material is preferred, as this results in smaller losses of allyl sulfide, total sulfur, antibacterial activity, and aroma.
· Multiple Cropping: Allium sativum L. “garlic” grows well with most plants, especially roses, carrots, beet and chamomile, but it inhibits the growth of legumes. This plant is a bad companion for alfalfa, each species negatively affecting the other.
· Plagues: Members of this genus are rarely if ever troubled by browsing deer.
· Planting: Plant out the cloves in late autumn for an early summer crop. They can also be planted in late winter to early spring though yields may not be so good. Plant the cloves with their noses just below the soil surface. If the bulbs are left in the ground all year, they will often produce tender young leaves in the winter.
In the North Hemisphere, when planted early in the spring, in February or March, the bulbs should be ready for lifting in August, when the leaves will be beginning to wither. Should the summer have been wet and cold, they may probably not be ready till nearly the middle of September. They must be kept thoroughly free from weeds and the soil gathered up round the roots from time to time.
· Flowering: Allium sativum L. “garlic” flowers between late spring and early summer.
· Light: Allium sativum L. “garlic” will do best in full sun but can be grown with satisfactory results in partial shade. It cannot grow in the shade.
· Moisture: Allium sativum L. “garlic” can tolerate periods without rain, but best results come from plants that receive regular watering.
· Harvest: Harvest Allium sativum L., common and rocambole varieties, when the tops fall over and turn brown, approximately after 8 months. The crop is harvested by pulling when the tops begin to turn yellow. Dry the bulbs (but not in direct sun) for a week, clean by removing the outer loose parts of the sheath and trim the roots close to the base, and then store in a dark, dry area, or braid the still-attached stems for a decorative and edible wreath. Bulbs to be saved for later planting can be stored in a plastic bag in the refrigerator for up to 8 months.
· Fertility: Allium sativum L. “garlic” is an obligate apomictic plant and is primarily propagated asexually by cloves. Flowering Allium sativum L. “garlic” plants can also be propagated by small bulbils that form in the umbel. On average the increase of Allium sativum L. “garlic” per generation is approximately seven, meaning that one Allium sativum L. “garlic” clove will produce seven cloves of sufficient size to produce the next generation.
Etoh (1986) described male-fertile Allium sativum L. “garlic” plants from Soviet Central Asia. Of course, plants grown from this first generation of seed are weak and commercially unacceptable.
Private companies have used these results to produce copious amounts of true Allium sativum L. “garlic” seed. The economic potential of this seed is enormous. Plants grown from true seed are either virus-free or have significantly reduced virus titers, eliminating the need for meristem culture to cleanse the plant of viruses (Walkey et al. 1987).
4. Garlic History
Allium sativum L. “garlic” has a very long history of use as a food and a medicine. Moreover, the use of Allium sativum L. both as a spice and medicinal predates written history. It is believed that since prehistory Allium sativum L. “garlic” was considered a miraculous bulb because of its medicinal and healthy properties.
This perennial, herbaceous and intensely odorous plant species has been cultivated since antiquity (maybe for more than 5 000 years) by nomad tribes of Central Asia due to its special flavor and medicinal properties. Sanskrit records document the use of Allium sativum L. “garlic” remedies approximately 5 000 years ago, while the Chinese have been using it for at least 3 000 years. It was largely consumed by the ancient Greeks and Romans, as we may read in Virgil's Eclogues.
Effectively, since Central Asia the use of Allium sativum L. “garlic” extended rapidly in other cultures such as old Egyptian, Roman, Greek, Indian and Middle Eastern Civilizations. Rations of Allium sativum L. “garlic” were given to the Egyptian laborers that built the pyramids because it was believed to confer strength and protect from disease.
The Codex Ebers, an Egyptian medical papyrus dating to about 1550 B.C., mentions Allium sativum L. “garlic” as an effective remedy for a variety of ailments, including hypertension, headache, bites, worms, and tumors. According to Pliny, Allium sativum L. “garlic” and Allium cepa L. “onion” were invocated as deities by the Egyptians at the taking of oaths.
In Greece, Allium sativum L. “garlic” was also widely used both as spice and medicine. Hippocrates and Aristotle cited numerous therapeutic uses for it. Besides, Olympic athletes in ancient Greece chewed a clove at the start of a competition, believing it increased their stamina. Allium sativum L. “garlic” was placed by the ancient Greeks (according to Theophrastus relates) on the piles of stones at cross-roads as a supper for Hecate, goddess of the darkness, night, and witchery.
Pliny gives an exceedingly long list of complaints, in which it was considered beneficial, and Galen eulogizes it as the rustics' Theriac, or Heal-All. One of its older popular names in this country was 'Poor Man's Treacle,' meaning theriac, in which sense we find it in Chaucer and many old writers.
Horace, however, records his detestation of Allium sativum L. “garlic”, the smell of which, even in his days (as much later in Shakespeare's time), was accounted a sign of vulgarity. He calls it 'more poisonous than hemlock,' and relates how he was made ill by eating it at the table of Maecenas. Among the ancient Greeks, persons who partook of it were not allowed to enter the temples of Cybele.
Homer, however, tells us that it was to the virtues of the 'Yellow Garlic' that Ulysses owed his escape from being changed by Circe into a pig, like each of his companions. Homer also makes Allium sativum L. “garlic” part of the entertainment which Nestor served up to his guest Machaon.
Allium sativum L. “garlic” was also widely used by the Romans. To prevent the plant running to leaf, Pliny (Natural History, XIX, 34, first century before Christ) advised bending the stalk downward and covering it with earth, seeding, he observed, may be prevented by twisting the stalk. Pliny also cites numerous therapeutic uses for Allium sativum L. “garlic”.
The Holly Bible mentions Allium sativum L. “garlic” as a food the Hebrews enjoyed during their sojourn in Egypt.
According to a Mohammedan legend, when Satan stepped out from the Garden of Eden after the fall of man, Garlic (Allium sativum L.) sprang up from the spot where he placed his left foot and Onion (Allium cepa L.) from that where his right foot touched.
Alexander Neckam, a writer in the twelfth century, recommends it as a palliative for the heat of the sun in field labor.
The French name Thériaque des pauvres (Theriac of the poor) reflects the medical value of Allium sativum L. “garlic”. In the Middle Ages, an expensive and complicated mixture of mostly very exotic ingredients called “theriac” was believed to be extremely powerful against every kind of illness (snake bite, bone fracture, plague, etc).
In 1721, during a widespread plague in Marseilles, four condemned criminals were recruited to bury the dead. The gravediggers proved to be immune to the disease. Their secret was a concoction they drank consisting of macerated Allium sativum L. “garlic” in wine. This became known as vinaigre des quatre voleurs (four thieves' vinegar), and it is still available in France today.
It is stated that during an outbreak of infectious fever in certain poor quarters of London, early 19th century, the French priests who constantly used Allium sativum L. “garlic” in all their dishes, visited the worst cases with impunity, whilst the English clergy caught the infection, and in many instances fell victims to the disease.
Mountstuart Elphinstone, in his book of travel written about 100 years ago, states that “the people in places where the Simoon is frequent eat Garlic (Allium sativum L.) and rub their lips and noses with it when they go out in the heat of the summer to prevent their suffering from the Simoon”.
In 1858, the antibiotic activity of Allium sativum L. was noted by Pasteur.
The use of Allium sativum L. “garlic” as an antiseptic was in great demand during World War I. It was widely employed in the control of suppuration in wounds. The raw juice is diluted with water, and put on swabs of sterilized Sphagnum moss, which are applied to the wound. Where this treatment has been given, it has been proved that there have been no septic results, and the lives of thousands of men have been saved by its use. During World War II, Allium sativum L. “garlic” was used by Albert Schwietzer in Africa for the treatment of amebic dysentery, and as an antiseptic in the prevention of gangrene.
Allium sativum L. “garlic” is the strongest flavored member of the onion family. Until quite recently, most civilizations used it medicinally and only their poor people ate it, while the priests and upper class citizens scorned its strong odor.
In England, Allium sativum L. “garlic”, apart from medicinal purposes, is seldom used except as a seasoning, but in the southern counties of Europe it is a common ingredient in dishes, and is largely consumed by the agricultural population. From the earliest times, indeed, Allium sativum L. “garlic” has been used as an article of diet.
Allium sativum L. “garlic” is mentioned in several Old English vocabularies of plants from the tenth to the fifteenth centuries, and is described by the herbalists of the sixteenth century from Turner (1548) onwards. It is stated to have been grown in England before the year 1540. In Cole's Art of Simpling we are told that cocks which have been fed on Allium sativum L. “garlic” are 'most stout to fight’, and that if a garden is infested with moles, Allium sativum L. “garlic” or leeks will make them 'leap out of the ground presently.'
In some parts of Europe, a superstition says that when you are running a race, the chewing of a piece of the bulb will prevent your competitors from getting ahead of you. In Hungary, another superstition says that when a jockey fastens a clove of Allium sativum L. “garlic” to the bit of his horse, any other racers running close to him and his horse will fall back the instant they smell the offensive odor. Allium sativum L. “garlic” is also said to be helpful in order to keep vampires away from you.
Allium sativum L. “garlic” contains compounds that are antibacterial, antifungal and reduce blood clotting. In order for the active ingredient that gives garlic its characteristic odor and its therapeutic effects to be released, the garlic clove must be cut or crushed. This releases an enzyme that causes the formation of allicin, the component responsible for the odor of Allium sativum L. “garlic” and medicinal activity.
The dietary virtues of Allium sativum L. “garlic” are well-known the world over. Allium sativum L. “garlic” has served mankind for centuries. The only problem with getting Allium sativum L. “garlic” into the diet has always been the distinct odor it leaves on the breath. Recent technological breakthroughs have now made it possible to manufacture "odorless" Allium sativum L. “garlic”.
Today, Allium sativum L. “garlic” is widely cultivated in most parts of the world for its edible bulb, which is used mainly as a flavoring in foods, although Allium sativum L. “garlic” has also medicinal properties accepted since many time ago.
This plant species has been used throughout history and throughout the world for the treatment of a wide variety of conditions. In general, Allium sativum L. “garlic” has been used as digestive, stimulant, diuretic, and antispasmodic; it has also been used to treat coughs, toothache, earache, dandruff, hypertension, atherosclerosis, hysteria, diarrhea, dysentery, diphtheria, vaginitis, and many other conditions. Many other possible properties are still being tested.
Although Allium sativum L. “ajo” has a wide range of well-documented effects, its most important clinical uses are in the areas of infection, cancer prevention, and cardiovascular disease.
In addition to the use of Allium sativum L. “garlic” preparations, Allium sativum L. “garlic” consumption as a food should be encouraged, despite its odor, in patients with high cholesterol levels and high blood pressure.
Allium sativum L. “garlic” and Allium sativum L. “garlic” preparations should also be encouraged in patients with diabetes, candidiasis, asthma, infections (particularly respiratory tract infections), and gastrointestinal complaints.
The innumerable medicinal benefits of Allium sativum L. “garlic” have been part of folk medicine during thousand years and are being confirmed by investigations carried out by numerous researchers all around the world. Today, we can affirm that there exists a great number of pharmacological evidence justifying its use as anti-hypertensive, antifungal, anti-microbial, anti-thrombosis, anti-hyperglycemic, and anti-lipemiant.
According to epidemiological and clinical studies, individuals eating regularly Allium sativum L. “garlic” show low incidence of some types of cancer, a low blood level of lipids, and a longer clotting time, all of which reduces risks of cardiovascular diseases.
5. Garlic Uses
5.1 Parts Used
Bulbs, bulbils, leaves, flowers, and seeds.
· Bulbs: The bulbs of Allium sativum L. “garlic” have been used throughout history both as spice and for the treatment of a wide variety of conditions. They are widely used, especially in southern Europe, as a flavoring in a wide range of foods, both raw and cooked, either fresh or dehydrated.
Allium sativum L. “garlic” bulbs are a wonderfully nutritious and health giving addition to the diet, but they have a very strong flavor and so are mainly used in very small quantities as a flavoring in salads and cooked foods. The bulbs can be up to 6 cm in diameter. Their bulbs are also used as a medicinal herb and are known as bulbus Allii sativi.
Chemical Composition of fresh Allium sativum L. “garlic” (per 100 g of fresh product):
- Water: 61%
- Proteins: 4 g
- Fat: 0,5 g
- Carbohydrate: 20 g
- Energy: 98 cal.
Chemical composition of the dehydrated bulb per 100 g (dry weight):
- Water: 0 g.
- Calories: 360.
- Protein: 13.5 g.
- Fat: 0.7 g.
- Carbohydrate: 82 g.
- Fiber: 3 g.
- Ash: 3.5 g.
- Calcium: 65 mg.
- Phosphorus: 400 mg.
- Iron: 4.3 mg.
- Sodium: 53 mg.
- Potassium: 1 250 mg.
- Vitamin A: 0 mg.
- Thiamine: 0.7 mg.
- Riboflavin: 0.2 mg.
- Niacin: 1.25 mg.
- Vitamin C: 35 mg.
Source: Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. 1985 ISBN 0-917256-20-4.
Notes: The figures given here are the median of a range given in the report.
The bulbs can be dried and used in slices or smashed. They are hot in odor and flavor. The fresh bulb is much more effective medicinally than stored bulbs; extended storage greatly reduces the anti-bacterial action.
· Bulbils: Hardneck garlic (Allium sativum var. ophioscorodon (Link) Doll) bulbils as well as the bulbs are used in the same way as common garlic (Allium sativum L.). Commercial names of some of these varieties are ‘Rocambole’ and ‘Serpent Garlic’.
Many consider ‘Rocambole’ to be more flavorful than regular garlic (Allium sativum L.), but it is harder to grow, and usually the bulbs are smaller, and they have a shorter storage life.
· Leaves: The young leaves can be used like chives. The leaves of Allium sativum L. “garlic” are used both raw and cooked. Chopped and used in salads, they are rather milder than the bulbs. The Chinese often cultivate Allium sativum L. “garlic” especially for the leaves; these can be produced in the middle of winter in mild winters.
· Flowers: The immature flower shoots, called garlic spears, are a delicacy in the Far East, and flowering stems are used as a flavoring and are sometimes sold in Chinese shops.
· Seeds: The sprouted seed is added to salads.
Allium sativum L. “garlic” is used as:
- anthelmintic (raw extract)
- insect repellent
Allium sativum L. “garlic” is used for/against:
- cholesterol levels
- platelet aggregation
- bile production and secretion
- bone fracture
- cancer prevention
- cardiovascular disease
- blood coagulation
- diabetes mellitus
- gastrointestinal complaints
- arterial hypertension (high blood pressure)
- hypercholesterolemia (high cholesterol levels)
- increases stamina
- infections (particularly respiratory tract infections)
- poor circulation
- prevention of gangrene
- reduce blood sugar
- snake bite
- thrombosis (treatment and prevention)
- treat coughs
The strongly scented and flavored bulbs are used mainly as a condiment raw or fried, roasted, confected, etc. in many dishes of the international gastronomy including meats, stews, and soups. Its strong and characteristic odor is markedly different in fresh and fried state. When frying, it is important not to let them char much, since it produces a bitter flavor. The pungency of fresh Allium sativum L. “garlic” vanishes after cooking or frying.
Usage of fried or cooked Allium sativum L. “garlic” is much more common. On heating, the pungency and strong odor get lost and the aroma becomes more subtle and less dominant, harmonizing perfectly with ginger, pepper, chilies and many other spices. Therefore, it is an essential ingredient for nearly every cuisine of the world.
Although native to Central Asia, Allium sativum L. “garlic” is one of the fundamental ingredients of the Mediterranean gastronomy. Allium sativum L. “garlic” is used both entire and chopped or grinded, and is part of numerous sauces, pickles, and other preparations.
Allium sativum L. “garlic” has been a common spice since the days of the Roman Empire, and it was extensively used from India to East Asia even before the Europeans arrived there. After the Age of Exploration, its use spread rapidly to Africa and both Americas. Curiously enough, in our days Northern Europeans seem to be the only ones who look on it with suspicion because of its strong smell, which is sometimes felt unpleasant.
Allium sativum L. “garlic” is much less popular in today's Europe, where it is used only with care, except the Southern European countries. Northerners seem to loathe the faint Allium sativum L. “garlic” odor that is emitted by Allium sativum L. “garlic” eaters even many hours after the Allium sativum L. “garlic” eating. There is no perfect remedy against it, but eating chopped parsley, hot showering and excessive tooth brushing will remove at least the greater part of it.
In Eastern cuisines (Chinese, Thai, or Indonesian cuisines, among others) it is used together with ginger in order to supply important odors and flavors.
In Northern Vietnam, freshly grated Allium sativum L. “garlic” is served in liberal amounts to spring rolls and soups. The latter is an example demonstrating the subtle effect that can be achieved by adding grated or squeezed raw Allium sativum L. “garlic” to a dish that already contains cooked Allium sativum L. “garlic”.
For a real taste sensation, many cooks recommend baking or roasting whole Allium sativum L. “garlic” bulbs until soft and creamy. However, some cuisines are fond of raw Allium sativum L. “garlic”. In parts of Austria, salads are prepared with vinegar, oil and minced Allium sativum L. “garlic”, and raw Allium sativum L. “garlic” appears in quite a multitude of Mediterranean sauces.
Prominent examples are the Provençal speciality aïoli, basically a mayonnaise based on olive oil and enriched with Allium sativum L. “garlic”; furthermore, Greek skordalia [σκορδαλιά] a paste made from cooked potatoes and raw Allium sativum L. “garlic”, and Turkish çaçık, a refreshing soup made from plain yoghurt, shredded cucumber, Allium sativum L. “garlic” and peppermint leaves. A similar, but thicker, sauce product is known as tsatsiki (also spelled tzatziki [τζατζίκι]) in Greece, where is often served to barbecued lamb souvlaki [σουβλάκι]. Many appetizers from West Asia contain some fresh Allium sativum L. “garlic”. Occasionally, minced Allium sativum L. “garlic” is spread along the edge of Italian pizza.
Allium sativum L. “garlic” finely cut and suspended in olive oil together with parsley leaves is often served to barbecued fish in Croatia. Cooks in Southern Europe tend to use Allium sativum L. “garlic” much more liberally.
Many Indian recipes add Allium sativum L. “garlic” in an early phase, and it is fried for a long time together with Allium cepa L. “onion” and other spices to provide the basic masala; in the finished dish, the Allium sativum L. “garlic” taste is no longer discernible, but has merged totally with the other components.
In contrast, although Indonesian and even Chinese stir-fries usually start with frying a few cloves of Allium sativum L. “garlic”, a faint Allium sativum L. “garlic” aroma persists until serving because of the much shorter cooking time. In Indonesian cuisine, mixtures based on minced Allium sativum L. “garlic”, ginger and chilies are frequently used to season meat pieces before roasting or grilling.
Thai cuisine, on the other hand, avoids frying of Allium sativum L. “garlic” (which is an essential component of its curry pastes), but prefers gentle simmering for spicy soups or creamy curries. Similar custom is found in Cambodia; pastes of Allium sativum L. “garlic”, together with chilies, lemon grass or ginger, are added to soups or stews.
In the southern states of the US, Allium sativum L. “garlic” is also very popular. The small town of Gilroy (in California, not far from San Francisco) claims to be the “garlic capital” of the world; although not quite true, the claim seems plausible to every visitor in end of July, when the annual “garlic festival” is held and Allium sativum L. “garlic” recipes are evaluated – allegedly, they even serve Allium sativum L. “garlic” ice cream. The Gilroy area is also the main Allium sativum L. “garlic” producer for the US market, as can easily be smelled at harvest time. There has been the saying that steaks can be marinated in the air of Gilroy. That's clearly exaggerated, but not necessarily much so.
Allium sativum L. “garlic” consumption is also high in Central America, where the bulbs are, among others, used for Mexican mole and salsa.
In recipes from North or Central Europe, Allium sativum L. “garlic” is normally cooked for a long time to reduce its odor; furthermore, its aroma is thereby sufficiently damped to fit better to the rather mild food of this region. Cooks tend to use Allium sativum L. “garlic” together with some Mediterranean herbs (thyme, bay leaves), but also with indigenous spices like juniper and caraway.
In Peru, Allium sativum L. “garlic” is a fundamental component for any dressing, together with Allium cepa L. “red onion” and chili. This bulb is eaten daily as dressing for rice.
Allium sativum L. “garlic” bulbs are available fresh or dried and as cloves, powdered, crushed, dehydrated, or as an ingredient in table salt. The storage of Allium sativum L. “garlic” has to be in a fresh, dry, well-ventilated room, and far from light. In humid environments they sprout and get rotten quickly. They do not have to be in the freezer.
The oil and the oleoresin from Allium sativum L. “garlic” are used extensively in the food industry as a flavoring in soups, stews, sauces, breads, cheeses, vinegars, pickles, processed foods, meats, sausages, and other dishes.
Raw Allium sativum L. “garlic” may also be pickled in vinegar or olive oil. Since some of the aroma of Allium sativum L. “garlic” is extracted by the liquid, pickled Allium sativum L. “garlic” is usually very mild. Herbal vinegar is commonly made with one or two Allium sativum L. “garlic” cloves per liter vinegar.
Today, Allium sativum L. “garlic” is one of the most popular spices in the world, and wherever it was introduced to, it met enthusiastic approval.
Antibiotic /Antimicrobial /Antiseptic
Allium sativum L. “garlic” is considered to be a natural antibiotic. Unlike most antibiotics, Allium sativum L. “garlic” will not deplete the body of flora. It has been shown to have broad-spectrum antimicrobial activity against many genera of bacteria, viruses, worms, and fungi. These findings support the historical use of Allium sativum L. “garlic” in the treatment of a variety of infectious conditions.
Externally, the juice obtained from Allium sativum L. “garlic” is an excellent antiseptic for treating wounds. It was intensively used during World War I. as an antiseptic. During World War II, Allium sativum L. “garlic” was used by Albert Schwietzer in Africa for the treatment of amebic dysentery, and as an antiseptic in the prevention of gangrene.
Furthermore, the healing properties of Allium sativum L. “garlic” make it an ideal agent for fighting colds and flu.
As far back as 1944, studies have demonstrated that both Allium sativum L. “garlic” juice and allicin inhibited the growth of Staphylococcus, Streptococcus, Bacillus, Brucella, and Vibrio species at low concentrations.
In more recent studies using serial dilution and filter paper disk techniques, fresh and vacuum-dried powdered Allium sativum L. “garlic” preparations were found to be effective antibiotic agents against many bacteria, as listed:
- Staphylococcus aureus
- Alpha- and beta-hemolytic Streptococcus
- Escherichia coli
- Proteus vulgaris
- Salmonella enteritidis
- Citrobacter sp.
- Klebsiella pneumoniae
In these studies, the antimicrobial effects of Allium sativum L. “garlic” were compared to commonly used antibiotics, including penicillin, streptomycin, chloramphenicol, erythromycin, and tetracycline. Besides confirming the well-known antibacterial effects of Allium sativum L. “garlic”, the studies demonstrated its efficacy in inhibiting the growth of some bacteria which had become resistant to one or more of the antibiotics.
On the other hand, the administration of Allium sativum L. “garlic” has been shown to significantly reduce the number of coliforms and anaerobes in the feces.
This plant species also produces inhibitory effects on gram-negative germs of the typhoid-paratyphoid-enteritis group; indeed it possesses outstanding germicidal properties and can keep amoebic dysentery at bay.
Allium sativum L. “garlic” has a very long folk history of use in a wide range of ailments, particularly ailments such as ringworm, Candida and vaginitis where its fungicidal, antiseptic, tonic and parasiticidal properties have proved of benefit.
Allium sativum L. “garlic” has demonstrated significant antifungal activity in many in vitro and in vivo studies. From a clinical perspective, inhibition of Candida albicans has the most significance as both animal and in vitro studies have shown Allium sativum L. “garlic” to be more potent than nystatin, gentian violet, and six other reputed antifungal agents.
In one study at a major Chinese hospital, Allium sativum L. “garlic” therapy alone was used effectively in the treatment of cryptococcal meningitis, one of the most serious fungal infections imaginable.
Allium sativum L. “garlic” has proved to be effective against the following infective fungi:
- Candida albicans
- Cryptococcus neoformans
Allium sativum L. “garlic” extracts have been shown to have anthelmintic activity against common intestinal parasites, including Ascaris lumbricoides (roundworm) and hookworms.
The antiviral effects of Allium sativum L. “garlic” have been demonstrated by its protection of mice from infection with intranasally-inoculated influenza virus, and by its enhancement of neutralizing antibody production when given with influenza vaccine.
The in vitro virus-killing effects of fresh Allium sativum L. “garlic”, allicin, and other sulfur components of Allium sativum L. “garlic” was determined against Herpes simplex type 1 and 2, Parainfluenza virus type 3, Vaccinia virus, Vesicular stomatitis virus, and Human rhinovirus type 2.
The different chemical constituents present in Allium sativum L. “garlic” have different virucidal activity. According to several experiments, the order for virucidal activity is:
- allyl methyl thiosulfinate
- methyl allyl thiosulfinate.
Ajoene was found in oil-macerates of Allium sativum L. “garlic” but not in fresh Allium sativum L. “garlic” extracts. No antiviral activity was found for alliin, deoxyalliin, diallyl disulfide, or diallyl trisulfide.
Fresh Allium sativum L. “garlic” extract was virucidal against all viruses tested. Virucidal activity of commercial products was dependent upon their preparation processes. Those products producing the highest level of allicin and other thiosulfinates had the best virucidal activity.
Allium sativum L. “garlic” has been found to be effective against the following viruses:
- Herpes simplex type 1 and 2
- Parainfluenza virus type 3
- Vaccinia virus
- Vesicular stomatitis virus
- Human rhinovirus type 2
Epidemiological studies in humans have shown that people that ingest Allium sativum L. “garlic” regularly show a low incidence of some kinds of cancer such as stomach, intestine, breast, lung, etc. It has been demonstrated that this regular eating diminishes cancer growth and reduces the number of tumors, and allicin, the active chemotherapeutic compound in Allium sativum L. “garlic”, is believed to play an important role in this anticancerous property.
Several centuries ago, the famous Greek physician Hippocrates prescribed eating Allium sativum L. “garlic” as treatment for cancers. Today, animal research and some human studies suggest this advice may have been well-founded. Several Allium sativum L. “garlic” components have displayed significant immune enhancing as well as anticancer effects.
In China, a study comparing populations in different regions found that death from gastric cancers in regions where Allium sativum L. “garlic” consumption was high was significantly less that in regions with lower Allium sativum L. “garlic” consumption.
Allium sativum L. “garlic” extracts and allicin have displayed potent antitumor effects in animal studies. Human studies have shown Allium sativum L. “garlic” inhibits the formation of nitrosamines (powerful cancer-causing compounds formed during digestion).
Lau, a researcher from the School of Medicine of the Loma Linda University, has identified 3 ways by which Allium sativum L. “garlic” supplies protection against cancer: i) inhibiting directly the metabolism of tumor cells, ii) preventing the initiation and reproduction of tumor cells, and iii) stimulating the immune system to be more efficient in fighting against cancer.
On the other hand, numerous researchers suggest that the chemoprotective effect of Allium sativum L. “garlic”, and one of the mechanisms of the chemoprotective action of the sulfur compounds present in it, is the activation of the detoxifying systems such as glutation-S-transferase, whose activity in the liver is increased significantly.
Several of the sulfur compounds derived from Allium sativum L. “garlic” possess an effect on the development and growing of cancer cells and in some cases they are as effective as chemostatics. An example of the latter is diallyl disulfur sulphoxid (DADS), which proved to be as effective as 5-fluorouracil, but less toxic, since some of the adverse effects of the latter one were diminished when utilized diallyl disulfur sulphoxid (DADS).
Furthermore, Selenium has been shown to reduce tumor growth in rats and may possess anticarcinogenic properties in humans (Ip et al. 1992).
In relation with the different ways of action of Allium sativum L. “garlic” on cancer, a definitive mechanism has not yet been well established, since there exists evidence of effects on several steps of carcinogenic metabolism and the regulation of tumor growth.
Immune Enhancing Effects
Allium sativum L. “garlic” is a source of selenium, which must be present in the body for proper immune response, and which acts as an antioxidant in combination with vitamin E. Rich in potassium, zinc, selenium, and Vitamins A & C, Allium sativum L. “garlic” is commonly used to fight infection, increase circulation and help prevent cardiovascular disease.
Animal research and some human studies suggest that some Allium sativum L. “garlic” components display significant immune enhancing effects, which may explain the traditional use of Allium sativum L. “garlic” in order to treat cancers.
Allium sativum L. “garlic” appears to be an important protective factor against heart disease and strokes via its ability to impact the process of atherosclerosis at many steps. There is substantial clinical information on Allium sativum L.’s beneficial effects on the cardiovascular system.
Although Allium sativum L. “garlic” has long been used in infectious conditions, a use supported by its antimicrobial and immune-enhancing properties, the primary clinical use of Allium sativum L. “garlic” has focused on its role in cardiovascular disease. Specifically, Allium sativum L. “garlic” is recommended primarily for its ability to lower cholesterol and blood pressure in the attempt to reduce the risk of dying prematurely from a heart attack or stroke.
The majority of studies showing a positive effect of Allium sativum L. “garlic” and Allium sativum L. “garlic” preparations in reducing the risk of cardiovascular mortality are those which use products which deliver a sufficient dosage of allicin. Since allicin is the component in Allium sativum L. “garlic” that is responsible for its easily identifiable odor, several manufacturers have developed highly sophisticated methods in an effort to provide the full benefits of Allium sativum L. “garlic” without odor.
These “odorless” Allium sativum L. “garlic” products concentrate for alliin because alliin is relatively "odorless" until it is converted to allicin in the body. Products concentrated for alliin and other sulfur components and stabilized in enteric-coated tablets provide all the benefits of fresh Allium sativum L. “garlic” but are more "socially acceptable."
Recent research has also indicated that Allium sativum L. “garlic” slows the development of arteriosclerosis and lowers the risk of further heart attacks in myocardial infarct patients.
The homeostatic homeostasis is conditioned basically by the equilibrium between 3 factors: i) endothelial lesion, ii) stasis, and iii) blood hyper-clotting, so that any event producing an alteration in any of them, will produce the alteration of this equilibrium and consequently a thrombosis or thrombus formation.
The thrombogenesis factors that participate in mechanisms that determine the local formation of thrombus and favor the lesion and evolution of the atherosclerotic plate and the risk factors or variables present in certain individuals that predispose them to suffer potentially an increased incidence of thrombotic phenomena favor thrombus formation, so that when acting on them we would be achieving the attenuation or prevention of the thrombus process.
There exists scientific evidence suggesting that Allium sativum L. “garlic” is able to exert an antithrombosis action when acting on these factors involved in the process of thrombosis. Some of the active principles obtained from this plant species diminish platelet aggregation and blood clotting. It is also well known that most members within the genus Allium possess unique thiosulfinates that condition antithrombotic benefits.
Platelets play a main role in hemostasis; hence, the inhibition of platelet aggregation results a valid way in order to prevent thrombosis. It is well known that the species within the genus Allium possess unique thiosulfinates that condition antithrombotic benefits and enhance in vitro antiplatelet activity (Ariga et al. 1981; Block et al. 1984; Lawson et al. 1992; Goldman et al. 1995; Bordia et al. 1996). This latter effect is important for cardiovascular health by reducing the probability that platelets aggregate in the blood, a major cause of heart attacks and strokes.
Recently, potent enzymes capable to inhibit the activity of adenosine deaminase (it degrades adenosine, an antiplatelet agent) and AMPc phosphodiesterase (it degrades AMPc to AMP). When these two enzymes are inhibited, AMPc and kinase levels increase, which provokes a diminishing in Ca2+ levels and platelet hypofunctionality, thus inhibiting platelet aggregation.
Many sulfur compounds present in Allium sativum L. “garlic” possess platelet anti-aggregation properties, such as allicin, adenosine, diallyltrishulphur, allyl 1,5-hexadieniltrisulfur and others, whose activity in vitro have been extensively proved. The antiplatelet activity has been primarily measured in vitro using platelet aggregometry. Correlations between measurements in vitro and in vivo have not been reported.
In 1984, professor Erick Block discovered a sulfurate compound considered the most potent antiplatelet agent derived from Allium sativum L. “garlic”, and called it ‘ajone’. This compound, obtained from allicin, is capable to inhibit in a dose-dependent manner, platelet aggregation induced by all the antagonists (ADP, epinephrine, collagen, arachidonic acid, PAF), through a mechanism different from the rest of the already known inhibitors (aspirin, indometacin, dipiridamol, prostacyclin) and powers synergically their action.
On the other hand, thanks to modern techniques of spectroscopy, Allium sativum L. “garlic” has been shown to be able to penetrate profoundly into the platelet membrane. As a result, a diminishing of viscosity in the inner region of the lipidic bilayer is observed, without affecting the outer hydrophilic zones of the lipidic bilayer. This increment in fluidity and decrement in molecular cohesion may explain the inhibition this compound produces on two major events of platelet aggregation, namely:
- Inhibition of the joining between fibrinogen and fibrinogen-receptor, integrin GPIib-IIIa (aIIb-b3) as a result of the interference in the expression of fibrinogen-receptor, which finally produces a reduction in the density of functional receptors.
- Inhibition of platelet-releasing reaction, both dense granules and A1 granules, through the interference in the fusion of granules with the plasmatic membrane (exocytose); hence, in the presence of ajoene there exists no segregation of granular compounds such as ADP or serotonin which could help to amplify the platelet aggregation phenomenon.
Finally, it must be noted that there is a significant environmental effect on the antiplatelet activity of Allium sativum L. “garlic” and related species. Goldman et al. (1996), for example, demonstrated that growing Allium cepa L. “onion” in the presence of high sulfur increased both the pungency and antiplatelet activity of the bulb. This means that high sulfur soils or medium should produce highly pungent bulbs that tend to show greater antiplatelet activity.
Blood coagulation/Platelet Aggregation Inhibition
As platelet aggregation, blood coagulation is part of the physiopathology of thrombosis, which plays a central role in thrombogenesis. Excessive platelet aggregation is also strongly linked to atherosclerosis, heart disease, and strokes. Allium sativum L. “garlic” preparations standardized for alliin content as well as Allium sativum L. “garlic” oil have demonstrated significant inhibition of platelet aggregation.
Both the intrinsic and extrinsic mechanisms are part of the successive steps corresponding to a mechanism of normal hemostasis, which, at a time, also constitute the beginning of thrombosis. Many are the controversies around the action exerted by Allium sativum L. “garlic” on the metabolism of arachidonic acid, although it has been observed that thromboxan B2 concentrations (unstable metabolite, with great aggregative and vasoconstrictor effects) diminish significantly as a result of the administration of Allium sativum L. “garlic”.
As a result of eating Allium sativum L. “garlic”, the plasmatic values of protrombine and factors VII, IX, and X of the coagulation cascade diminish, which, according to accumulated evidences, is due to the inhibition of the production of these elements in the liver.
In one study, 120 patients with increased platelet aggregation were given either 900 mg/day of a dried Allium sativum L. “garlic” preparation containing 1.3% alliin or a placebo for 4 weeks. In the Allium sativum L. “garlic” group, spontaneous platelet aggregation disappeared, the microcirculation of the skin increased by 47.6%, plasma viscosity decreased by 3.2%, diastolic blood pressure dropped from an average of 74 mmHg to 67 mmHg, and fasting blood glucose concentration dropped from an average of 89.4 mg/dl to 79 mg/dl.
Hypolipemic Action /Hyperlipemia
Hyperlipemia induced by and excessive ingestion of lipids produces an increase in the plasmatic fibrinogen concentrations and a decrease of the fibrinolytic activity and time of coagulation, effects that can be diminished considerably by Allium sativum L. “garlic”.
The hypolipemic affects of Allium sativum L. “garlic” have been widely demonstrated through a great number of researches performed on experimental models and humans, in which different formulations of this plant species have been used (water, extracts, alcohol extracts, capsules of powdered Allium sativum L. “garlic”, etc.) and crude Allium sativum L. “garlic” (cloves).
In experimental animal models, Allium sativum L. “garlic” has been observed to prevent accumulation of lipids in the aorta, in spite of actual high cholesterol levels which, according to Orekhov, may be a consequence of the inhibition that Allium sativum L. “garlic” produces in the capacity of modified LDLs, and degradation of cholesterol esters bound to LDLs, which reduces significantly the intracellular accumulation of these esters.
The use of Allium sativum L. “garlic” also involves a considerable reduction in triglyceride levels due to the production of a marked inhibition in the main lipogenesis enzymes (acetyl CoA carboxilase and fatty acid synthase).
Finally, it has been proved in animals that the essential oil of Allium sativum L. “garlic” is more effective than clofibrate in order to diminish total cholesterol and prevent accumulation of lipids in the aorta. This proves that its use as hypolipemiant agent may be a very efficacious therapeutic alternative.
Arterial Hypertension /Antihypertensive
It is well known that the increment of both systolic and diastolic tension constitute a risk factor for cardiovascular diseases.
Arterial hypertension is considered a high thrombogenic factor since it is able to destroy or alter the functionality of endothelial cells, besides of increasing risk of atherosclerosis.
Recent studies show that Allium sativum L. “garlic” is able to increase, in vivo, the activity of nitric oxide synthase, enzyme responsible of the formation of nitric oxide or endothelium-derived relaxant factor (EDRF), powerful vasodilator, whose basal and constant releasing (short amounts) contributes the maintaining of systemic blood pressure within normal value.
This was justified when demonstrating that Allium sativum L. “garlic” prevented nitric oxide inhibition-induced hypertension. This hypotensive effect is powered by the fact that Allium sativum L. “garlic” is capable to inhibit the activity of Angiotensin I converting enzyme, which is in charge of catalyzing the conversion of Angiotensin I to Angiotensin II, powerful vasoconstrictor involved in the increment of arterial tension.
There exist a number of antihypertensive drugs whose action is produced through the latter mechanism, which in case of Allium sativum L. “garlic” occurs due to the presence of g-glutamyl cysteine, a natural inhibitor of Angiotensin I-converting enzyme.
It has also been demonstrated that water extracts of Allium sativum L. “garlic” and isolated components of Allium sativum L. “garlic” (allicin and ajoene) open potassium canals that cause hyperpolarization of membranes, which leads a diminishing of calcium levels in smooth muscle cells; this produces a vasodilatation as a result of intracellular calcium decrement.
Recent clinical studies have shown a hypotensive effect of Allium sativum L. “garlic” on both systolic and diastolic blood pressure values. Individuals treated with Allium sativum L. “garlic” reduced their blood pressure in 5% to 10%.
Effectively, Allium sativum L. has demonstrated hypotensive action in both experimental animals and humans with hypertension. A meta-analysis of published and unpublished randomized controlled trials of Allium sativum L. “garlic” preparations was conducted to determine the effect of Allium sativum L. “garlic” on blood pressure relative to placebo.
Eight trials (7 double-blind, 1 single-blind) were identified as meeting analytical criteria. A total of 415 subjects were included in the analysis. All trials used a dried Allium sativum L. “garlic” powder standardized to contain 1.3% alliin at a dosage of 600 mg to 900 mg daily (corresponding to 7.8 mg and 11.7 mg of alliin or approximately 1.8 g to 2.7 g of fresh Allium sativum L. “garlic” daily).
The meta-analysis concluded that Allium sativum L. “garlic” preparations designed to yield allicin can lower systolic and diastolic blood pressure over a one to three month period. The typical drop from pooled data was 11 mm Hg in the systolic and 5.0 mm Hg in the diastolic. This degree of blood pressure reduction in hypertensives can be quite significant.
It is estimated that if the blood pressure-lowering effects of Allium sativum L. can be maintained, the risk of stroke may be reduced by 30%-40% and the risk of heart attack by 20%-25%.
An extract obtained from Allium sativum L. “garlic” has demonstrated significant anti-inflammatory activity in experimental models of inflammation. This activity is probably a result of Allium sativum L.’s inhibition of the formation of inflammatory compounds.
Allium sativum L. “garlic” (and Allium cepa L. “onion”) has often been used in the treatment of diabetes. Allicin has been shown to have significant hypoglycemic action. This effect is thought to be due to increased hepatic metabolism, increased release of insulin and/or insulin-sparing effect. The latter mechanism appears to be the major factor, as allicin and other sulfhydryl compounds in Allium sativum L. “garlic” and Allium cepa L. “onion” compete with insulin (also a disulfide protein) for insulin-inactivating compounds, which results in an increase in free insulin.
Allium sativum L. “garlic” possesses diuretic activity. This plant species has been known to detoxify the body by cleansing the kidneys and increasing urine flow.
It is well known that Allium sativum L. “garlic”, Allium cepa L. “onion” and probably all the plant species within the genus Allium, possess unique thiosulfinates with antioxidant activity (Yang et al. 1993; Yin and Cheng 1998). Allium sativum L. “garlic” is also a source of selenium, which acts as an antioxidant in combination with vitamin E.
It is well known that the species within the genus Allium possess unique thiosulfinates that condition antithrombotic benefits, including reduced serum cholesterol (Bakhsh and Khan 1990). Hence, several studies have shown that Allium sativum L. “garlic” is able to diminish blood levels of total cholesterol, mainly the most pernicious type, i. e., bound with low density lipoproteins (LDL). This reduction can be explained by the inhibition of cholesterol synthesis in the liver, since it is able to inhibit enzymes essential for this process (b-hydroxy-b-methylglutaryl CoA synthase and b-hydroxy-b methylglutaryl CoA reductase).
On the other hand, Allium sativum L. “garlic” is known to be able to inhibit the activity of acyl CoA cholesterol acyl transferase, which participates in the formation of cholesterol esters, and stimulate cholesterol ester hydrolase, which degrades cholesterol esters. The influence on the activity of both enzymes may explain the reduction of cholesterol esters which constitute the major component in the excessive accumulation of fats in cells. This inhibition occurs both in atherosclerotic and normal cells.
In experimental animal models, Allium sativum L. “garlic” has been observed to prevent lipid accumulation in the aorta, in spite of existing a high cholesterol level which, according to Orekhov, may be a consequence of the inhibition that Allium sativum L. “garlic” produces on the ability of modified LDLs and degradation of cholesterol esters bound to LDL, which reduces significantly the intracellular accumulation of these esters.
According to the results from numerous double-blind, placebo-controlled studies in patients with initial cholesterol levels greater than 200, supplementation with commercial preparations providing a daily dose of at least 10 mg alliin or a total allicin potential of 4,000 µg can lower total serum cholesterol levels by about 10% to 12%; LDL cholesterol will decrease by about 15%; HDL cholesterol levels will usually increase by about 10%; and triglyceride levels will typically drop 15%.
Although the effects of supplemental Allium sativum L. “garlic” preparations on cholesterol levels are modest, the combination of lowering LDL and raising HDL can greatly improve the LDL to HDL ratio, a significant goal in the prevention of heart disease and strokes. In addition, Allium sativum L. “garlic” preparations standardized for alliin content exert several other beneficial effects in preventing heart disease and strokes.
Allium sativum L. “garlic” also produces a stimulation on bile releasing from gallbladders (bile contains cholesterol and related compounds), so that cholesterol elimination is encouraged.
Finally, it has been proved in animals that the essential oil of Allium sativum L. “garlic” is more effective than clofibrate in order to diminish total cholesterol and prevent lipid accumulation in the aorta. This means that the use of this essential oil as hypolipemiant agent may be a very efficacious therapeutic alternative.
In addition to taking an Allium sativum L. “garlic” supplement, individuals with high cholesterol levels should eat more Allium sativum L. “garlic” and Allium cepa L. “onion” as increased dietary intake of Allium sativum L. “garlic” and Allium cepa “onion” can also lower cholesterol levels.
In a 1979 population study, researchers studied three populations of vegetarians in the Jain community in India who consumed differing amounts of Allium sativum L. “garlic” and Allium cepa L. “onion”. Numerous favorable effects on blood lipids, as shown in the table below, were observed in the group that consumed the largest amount.
Effects of Garlic and Onion Consumption on Serum Lipids under Carefully Matched Diets
Blood fibrinogen levels were highest in the group eating no onions or Allium sativum L. “garlic” The study is quite significant because the subjects had nearly identical diets, except in Allium sativum L. and Allium cepa ingestion.
Allium sativum L. “garlic” has also been used for treating respiratory problems such as bronchitis and asthma.
Epidemiological studies have suggested that fibrinogen is a major primary risk factor for cardiovascular disease. Fibrinogen is an "acute phase" protein involved in the clotting system. However, it plays many other important roles including several which promote atherosclerosis, such as acting as a co-factor for platelet aggregation, determining the viscosity of blood, and stimulating the migration and proliferation of smooth muscle cells in the intima of the artery walls.
Early clinical studies stimulated detailed population studies on the possible link between fibrinogen levels and cardiovascular disease. The first such study was the Northwick Park Heart Study in the U.K. This large study involved 1,510 men aged 40 to 64 years who were randomly recruited and tested for a range of clotting factors, including fibrinogen. At 4 years follow-up, a stronger association was found between cardiovascular deaths and fibrinogen levels than for cholesterol. This association has been confirmed in five other prospective epidemiological studies.
The clinical significance of these findings can be summarized as follows:
1. Fibrinogen levels should be determined and monitored in patients with, or at high risk for, coronary heart disease or stroke.
2. Allium sativum L. “garlic” and other natural therapies which promote fibrinolysis (e.g., omega-3 oils, bromelain, capsicum, etc.) may offer significant benefit in the prevention of heart attacks, strokes, and other thromboembolic events.
Allium sativum L. “garlic” preparations standardized for alliin content as well as Allium sativum L. “garlic” oil, and both fried and raw Allium sativum L. “garlic” have been shown to significantly increase serum fibrinolytic activity in humans. This increase occurs within the first six hours after ingestion and continues for up to 12 hours.
Prevention of LDL-Oxidation
There is growing evidence that lipoprotein (LDL) oxidation plays a significant role in the development of atherosclerosis. Accordingly, substances which prevent oxidation of LDL slow down atherosclerosis. Antioxidants vitamin E, vitamin C, and beta-carotene have all been shown to offer protection against LDL oxidation and heart disease.
Allium sativum L. is known to exert antioxidant activity, but until recently, there were no studies examining its effects on LDL oxidation. Healthy human volunteers given 600 mg/day of an Allium sativum L. preparation providing 7.8 mg alliin for two weeks had a 34% lower susceptibility to lipoprotein oxidation compared to controls. These results are quite significant given the short amount of time they took to produce coupled with the importance of reducing lipoprotein oxidation.
Daily use of Allium sativum L. “garlic” in the diet has been shown to have a very beneficial effect on the body, especially the blood system and the heart. For example, demographic studies suggest that Allium sativum L. “garlic” is responsible for the low incidence of arteriosclerosis in areas of Italy and Spain where consumption of the bulb is heavy.
Allium sativum L. “garlic” appears to be an important protective factor against heart disease and strokes via its ability to impact the process of atherosclerosis at many steps. Recent research indicates that Allium sativum L. “garlic” slows the development of arteriosclerosis.
During the atherosclerotic process, lipids play a determinant role in the formation of the atheroma, in whose surface propitious conditions for the production of thrombosis are present due to the removal of the endothelium or alteration of its properties. On the other hand, some lipids favor the activation of coagulation factors and platelets; all these increases the risk of thrombus formation.
Diabetes mellitus includes a syndrome characterized by glucose intolerance, which establishes a condition of chronic hyperglycemia.
In diabetic individuals, there exist a series of factors that contribute to provoke the prothrombotic state, as elevation of fibrinogen levels, reduction of plaminogen tissue activator activity (PA) and premature development of atherosclerosis in big, medium, and small caliber arteries.
Recent research indicates that Allium sativum L. “garlic” reduces glucose metabolism in diabetics. Effectively, aliin, a phytochemical present in Allium sativum L. “garlic” and whose chemical name is S-Alyl-L-cisteine sulfoxid has a confirmed antidiabetic effect. It posses the same efficacy of glibenclamide and insulin in rats with Alloxan-induced diabetes.
Furthermore, S-allyl-L-cysteine sulfoxid is capable to exert a better control of lipid peroxidation than glibenclamide and insulin, besides the in vitro insulin secretion from b cells isolated from normal rats.
An extract of the plant can be used as a fungicide. It is used in the treatment of blight and mould or fungal diseases of tomatoes and potatoes. If a few cloves of Allium sativum L. “garlic” are spread amongst stored fruit, they will act to delay the fruit from rotting.
The growing plant is said to repel insects, rabbits and moles. The juice from the bulb is used as an insect repellent. It has a very strong smell and some people would prefer to be bitten. The juice can also be applied to any stings in order to ease the pain. Three to four tablespoons of chopped Allium sativum L. “garlic” and 2 tablespoons of grated soap can be infused in 1 liter of boiling water, allowed to cool and then used as an insecticide.
Allium sativum L. “garlic” has also been shown to aid detoxification of chronic lead poisoning.
Popularly used as a digestive aid, Allium sativum L. “garlic” increases bile production while enhancing digestion and reducing stomach gases. It is also a carminative, anti-spasmodic and digestant, making it useful in cases of flatulence, nausea, vomiting, colic, and indigestion. Used in cookery it is a great aid to digestion, and keeps the coats of the stomach healthy.
An excellent glue can be made from the juice. When this glue is spread on glass it enables a person to cut clean holes in the glass. The juice is also used as a glue in mending glass and china.
The juice of Allium sativum L. “garlic”, and milk of Allium sativum L. “garlic” made by boiling the bruised bulbs in milk is used as a vermifuge.
Disorders of the Lungs
Syrup of Allium sativum L. “garlic” is an invaluable medicine for asthma, hoarseness, coughs, difficulty of breathing, and most other disorders of the lungs, being of particular virtue in chronic bronchitis, on account of its powers of promoting expectoration. It is made by pouring a quart of water, boiled hot, upon a pound of the fresh root, cut into slices, and allowed to stand in a closed vessel for twelve hours, sugar then being added to make it of the consistency of syrup. Vinegar and honey greatly improve this syrup as a medicine. A little caraway and sweet fennel seed bruised and boiled for a short time in the vinegar before it is added to the Allium sativum L. “garlic”, will cover the pungent smell of the latter.
A homemade remedy for asthma, that was formerly most popular, is a syrup of Allium sativum L. “garlic”, made by boiling the bulbs till soft and adding an equal quantity of vinegar to the water in which they have been boiled, and then sugared and boiled down to a syrup. The syrup is then poured over the boiled bulbs, which have been allowed to dry meanwhile, and kept in a jar. Each morning a bulb or two is to be taken, with a spoonful of the syrup.
Syrup made by melting 1 1/2 OZ. of lump sugar in 1 OZ. of the raw juice of Allium sativum L. “garlic” may be given to children in cases of coughs without inflammation.
The successful treatment of tubercular consumption by Allium sativum L. “garlic” has been recorded, the freshly juice, diluted with equal quantities of water, or dilute spirit of wine, being inhaled antiseptically. These results, however, have never been scientifically analyzed.
Bruised and mixed with lard, Allium sativum L. “garlic” has been proved to relieve whooping-cough if rubbed on the chest and between the shoulder-blades.
Although not proved, an infusion of the bruised bulbs, given before and after every meal, has been considered of good effect in epilepsy.
A clove or two of Allium sativum L. “garlic”, pounded with honey and taken two or three nights successively, is popularly said to be good in rheumatism.
Allium sativum L. “garlic” has also been employed with advantage in dropsy, removing the water which may already have collected and preventing its future accumulation. It is stated that some cases of dropsy have been cured by it alone.
If sniffed into the nostrils, it will revive a hysterical sufferer. Amongst physiological results, it is reported that Allium sativum L. “garlic” makes the eye retina more sensitive and less able to bear strong light.
In olden days, Allium sativum L. “garlic” was employed as a specific for leprosy. It was also believed that it had most beneficial results in cases of smallpox, if cut small and applied to the soles of the feet in a linen cloth, renewed daily.
It is sometimes externally applied in ointments and lotions, and as an antiseptic, to disperse hard swellings, also pounded and employed as a poultice for scrofulous sores. It is said to prevent anthrax in cattle, being largely used for the purpose.
6. Garlic Phytochemicals
Allium sativum L. “garlic” contains from 0.1% to 0.36% of a volatile oil composed of sulfur-containing compounds:
- diallyl disulfide
- diallyl trisulfide
- s-methyl-L-cysteine sulfoxide
- s-propyl-L-cysteine sulfoxide
- other compounds.
These volatile compounds are generally considered to be responsible for most of the pharmacological properties of Allium sativum L.
Other constituents of Allium sativum L. include:
- alliin (S-allyl-L-cysteine sulfoxide)
- S-methyl-L-cysteine sulfoxide
- protein (16.8%, dry weight basis)
- high concentrations of trace minerals (particularly selenium)
- enzymes (alliinase, peroxidase, and
Allium sativum L. “garlic” contains a wealth of sulphur compounds; sulphur compounds of this kind are typical for the onion family. The characteristic flavor, aroma, and active principle in Allium sativum L. “garlic” are found only upon rupture of the cell membranes, which allows the enzyme alliinase to produce the disulfide of the characteristic Allium sativum L. “garlic” odor.
The strong odor of Allium sativum L. “garlic” is due mostly to a sulfide called allicin. For those who do not like its odor, a standardized an encapsulated "odorless" form can eliminate any unpleasant odor and taste.
· Selenium: Allium sativum L. “garlic” is a source of selenium, which must be present in the body for proper immune response, and which acts as an antioxidant in combination with vitamin E.
Selenium is a micronutrient required in small amounts in the human diet (Young 1981). Selenium has been shown to reduce tumor growth in rats and may possess anticarcinogenic properties in humans (Ip et al. 1992). Selenium is closely related to sulfur, is efficiently taken up by several Allium species (Morris 1970), and may be substituted for sulfur in metabolic pathways.
When Allium cepa L. “onion” or Allium sativum L. “garlic” is grown under higher selenium concentrations, the amount of this element relative to sulfur is increased and selenium-enhanced Allium cepa L. “onion” and Allium sativum L. “garlic” can be artificially produced.
· Vitamins and other Minerals: Allium sativum L. “garlic” is also rich in potassium, zinc, and vitamins A and C.
· Allicin.- Because of the activity of allinase on the compound alliin (S-2-propenyl-L-cysteine sulfoxide), an enzyme present in the bulbs, aliin transforms into allicin (diallyl disulphide oxide) when cells are damaged. This compound is mainly responsible for Allium sativum L.’s pungent odor and taste. Its biological function is to repel herbivorous animals.
The essential oil of Allium sativum L. yields approximately 60% of its weight in allicin after exposure to alliinase. The allinase is inactivated by heat, which accounts for the fact that cooked Allium sativum L. produces neither as strong an odor as raw Allium sativum L. nor nearly as powerful physiological effects.
Allicin is deactivated to diallyl disulphide; therefore, minced Allium sativum L. “garlic” changes its aroma if not used immediately. In the essential oil from steam distillation, diallyl disulphide (60%) is found besides diallyl trisulphide (20%), diallyl sulfide, ajoene and minor amounts of other di- and polysulphides.
Alliinase is located in the vacuoles and is released when the cells of Allium sativum L. “garlic” are cut, damaged, or bruised (Lancaster and Collin 1981). The enzyme acts quickly upon the cytoplasmic ASCOs to produce a suite of thiosulfinates. The total flavor experience is the result of the action of alliinase on the different amounts of individual flavor precursors (Lancaster and Boland 1990).
· Aliin: This compound, whose chemical name is S-allyl-L-cysteine sulfoxid, has a proved antidiabetic effect. It is as effective as glibenclamide and insulin in alloxan-induced diabetic rats.
For the two drugs previously mentioned, hepatic conversion of labile acetate into cholesterol increased significantly. This phenomenon does not occur when a treatment with Allium sativum L. “garlic” is applied, which means that a risk factor is avoided.
Likewise, S-allyl-L-cysteine sulfoxid is capable to exert a better control on lipid peroxidation than glibenclamide and insulin, besides in vitro insulin secretion of b cells isolated from normal rats.
· Oil: The active properties of Allium sativum L. “garlic” depend on a pungent, volatile, essential oil, which may readily be obtained by distillation with water. The oil of Allium sativum L. “garlic” is obtained by steamed distillation of the crushed fresh bulbs. The essential oil of Allium sativum L. “garlic” yields approximately 60% of its weight in allicin after exposure to alliinase.
This oil is rich in sulphur, but contains no oxygen. The peculiar penetrating odor of Allium sativum L. “garlic” is so diffusive that even when the bulb is applied to the soles of the feet, its odor is exhaled by the lungs.
7. Garlis Dosage and Contraindications
Allium sativum L. “garlic” is commercialized in entire bulbs, peeled cloves, powdered, as salt, in granules, flakes, paste, or pickled. It is most advisable to purchase it fresh, tender, and firm and use it in the desired way: chopped, crushed, or smashed in a mortar.
The modern use of Allium sativum L. “garlic” features the use of commercial preparations designed to offer the benefits of Allium sativum L. “garlic” without the odor. Preparations standardized for alliin content provide the greatest assurance of quality. The marketplace is swamped with Allium sativum L. “garlic” products with each manufacturer claiming their product is the best.
Based on a great deal of clinical research, the dosage of a commercial Allium sativum L. “garlic” product should provide a daily dose equal to at least 4,000 mg of fresh Allium sativum L. “garlic” This dosage translates to at least 10 mg alliin or a total allicin potential of 4,000 µg.
- In cases of arterial tension, it is recommended about 30 drops of alcoholic extract as a remedy. To be administered by the mouth or intravenously.
- Take one (1) capsule (580 mg), two (2) to three (3) times each day with water at mealtimes.
- Juice: 10 to 30 drops.
- Syrup: 1 drachm (1/8 ounce)
- Tincture: 1/2 to 1 drachm (1/16 to 1/8 ounce).
- Wine of Allium sativum L. “garlic”: made by macerating three or four bulbs in a quart of proof spirit is a good stimulant lotion for baldness of the head.
- Used in cookery it is a great aid to digestion, and keeps the coats of the stomach healthy. For this reason, essential oil is made from it and is used in the form of pills.
- If a very small piece is chopped fine and put into chicken's food daily, it is a sure preventative of the gapes. Pullets will lay finer eggs by having Allium sativum L. “garlic” in their food before they start laying, but when they commence to lay it must be stopped, otherwise it will flavor the eggs.
- Those scheduled for surgery should inform their surgeon if they are taking Allium sativum L. “garlic” supplements.
- Because of anti-clotting properties of Allium sativum L. “garlic”, people taking anticoagulant drugs should check with their doctor before taking this product.
- There have been cases of poisoning caused by the consumption, in large quantities and by some mammals, of this species. Dogs seem to be particularly susceptible.
- Contact with Allium sativum L. “garlic” can cause dermatitis in individuals particularly sensitive.
- For the vast majority of individuals, Allium sativum L. is nontoxic at the dosages commonly used. For some, however, it can cause irritation to the digestive tract, while others are apparently unable to effectively detoxify allicin and other sulfur-containing components.
- Prolonged feeding of large amounts of raw Allium sativum L. “garlic” to rats results in anemia, weight loss and failure to grow.
- Although the exact toxicity of Allium sativum L. has yet to be definitively determined, side effects are rare at the dosage recommended above.
- Allium sativum L. “garlic” preparations have been fatal to children.
7. Garlic Bibliography and References
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