Garlic principle

Garlic supplements - powder tablets or capsules, steam-distilled oil, vegetable oil macerate extract, or extract aged in dilute alcohol - are widely available and are taken by millions. Since the active principle, allicin, is not present in garlic bulb, the supplements rely on the presence of precursor alliin and enzyme alliinase. In tests on 24 commercial brands of enteric-coated tablets, all except one gave low dissolution allicin release 83% of the brands released less than 15% of their potential allicin.78,79 Relevant factors were impaired enzyme activity caused by excipients and slow tablet disintegration. Caveat emptor ... 

During the Second World War, women in the Netherlands had to resort to eat tulip bulbs. They blamed their frequent menstmal upsets and ovulation failures on this diet. Harborne (1993) listed garlic, oats, barley, rye grass, coffee, sunflower, parsley, and potato tubers as having effects on estrus in women, but also cows. The active principle may not be a hormone but rather compounds that... 

A number of studies have focused on identifying the active antimicrobial principles in fresh garlic extract. Allicin has been identified as the active agent in garlic extracts. The antifungal activity of allicin has been shown to depend on the sulfhydryl moiety because activity is destroyed by thiols such as L-cysteine, glutathione, and mercaptoethanol. Ajoene, a compound found in oil-macerated garlic, has also been shown to have antimicrobial activity (Ali et al., 2000). 

Prasad, K. et ah, Antioxidant activity of allicin, an active principle in garlic, Mol. Cell. Biochem., 148,183-189, 1995. 

Alkyl sulfides and thiols. Some alkyl thiols and sulfides, notably those from commonly ingested Allium sativum (garlic) and Allium cepa (onion) (Alliaceae), are variously bioactive as odorants and antimicrobials. Propanethial S-oxide (CH3-CH2-CH=S=0) is a lachrymatory irritant principle of onion. Allicin (S-oxodiallydisulfide CH2=CH—CH2-SO-S-CH2— CH=CH2), diallyldisulfide (CH2=CH-CH2-S-S-CH2-CH=CH2) and diallylsulfide (CH2=CH—CH2—S—CH2-CH=CH2) are major odorants of garlic that are reactive and irritant because of the allyl groups. Dimethyl disulfide (CH3—S—S-CH3), dipropyl disulfide (CH3-CH2-CH2-S-S-CH2-CH2-CH3), methyl allyl disulfide (CH3-S-S-CH2-CH=CH2) and propane-1-thiol (CH3-CH2—CH2—SH) are further Allium odorants. Methane thiol (methyl mercaptan CH3—SH) is a widespread plant volatile and notably derives from anaerobic bacterial degradation of cysteine as in human flatus and bad mouth odour. The aliphatic disulfides allicin and ajoene inhibit proinflammatory expression of iNOS. 

Srivastava KC, Tyagi OD. Effects of a garlic-derived principle (ajoene) on aggregation and arachidonic acid metabolism in human blood platelets. Prostagland Leukotr Essent Fatty Acids 1993 49 587-595. 

Stoll A, Seebeck E (1951) Chemical investigations on alliin, the specific principle of garlic. Adv Enzymol Relat Areas Mol Biol 11 377-400... 

At present, a limited number of studies on immune stimulatory constituents in garlic were reported and the active principle(s) is far from conclusive. A variety of constituents in garlic may contribute to its effects, i.e. since the immune system involves several types of immuno-responder cells, different constituents may affect different responders. For example, our recent results suggest that AGE contains two types of SH-compounds one stimulates interleukin-2 release from mouse spleen cells and the other suppresses the release (unpublished data). 

Weisberger AS, Pensky J (1957) Tumor-inhibiting effects derived from an active principle of garlic (Allium sativum). Science 126 1112-1114... 

Apitz-Castro, R., Escalante, J., Vargas, R., and Jain, M.K. 1986a. Ajoene, the antiplatelet principle of garlic, synergistically potentiates the antiaggregatory action of prostacyclin, foiskolin, indo-methacin and dypiridamole on human platelets. Thromb Res 42(3) 303 311. 

Sheen, L.Y., Wu, C.C., Lii, C.K., and Tsai, S.J. 2001. Effect of diallyl sulfide and diallyl disulfide, the active principles of garlic, on the aflatoxin Bl-induced DNA damage in primary rat hepa-tocytes. Toxicol Lett 122 l) 45—52. 

The chemistry of garlic flavor parallels that of onion and Freeman and Whenham [72] established that any differences were due to qualitative and quantitative differences in the precursors present. The principle substrate is S-(2-propenyl)l-cysteine sulfoxide, which when acted upon by alliinase produces allyl thiosulflnate (allicin)... 

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