Organosulfur compounds from garlic

A climbing wall is an artificially constructed wall with grips for hands and feet, usually used for indoor climbing, but sometimes located outdoors. Some are brick or wooden constructions, but on most modern walls, the material most often used is a thick multiplex board with holes drilled into it.

S-allyl-L-cysteine sulfoxide (alliin) accounts for approximately 80% of cysteine sulfoxides in garlic (1). When raw garlic cloves are crushed, chopped, or chewed, an enzyme known as alliinase is released. Alliinase catalyzes the formation of sulfenic acids from L-cysteine sulfoxides . Sulfenic acids spontaneously react with each other to form unstable compounds called thiosulfinates. In the case of alliin, the resulting sulfenic acids react with each other to form a thiosulfinate known as allicin (half-life in crushed garlic at 23°C is 2.5 days).

The formation of thiosulfinates is very rapid and has been found to be complete within 10 to 60 seconds of crushing garlic. Allicin breaks down in vitro to form a variety of fat-soluble organosulfur compounds , including diallyl trisulfide (DATS), diallyl disulfide (DADS), and diallyl sulfide (DAS), or in the presence of oil or organic solvents, ajoene and vinyl thins (2). In vivo, allicin can react with glutathione and L-cysteine to produce S-allylmercaptoglutathione (SAMG) and S-allylmercaptocysteine (SAMC), respectively (3).

Crushing garlic does not change its γ-glutamyl-L-cysteine peptide content. γ-Glutamyl-L-cysteine peptides include an array of water-soluble dipeptides, including γ-glutamyl-S-allyl-L-cysteine, γ-glutamylmethylcysteine, and γ-glutamylpropylcysteine .

Water-soluble organosulfur compounds, such as S-allylcysteine and SAMC , are formed from γ-glutamyl-S-allyl-L-cysteine during long-term incubation of crushed garlic in aqueous solutions, as in the manufacture of aged garlic extracts (see Food sources).

Allium vegetables, including garlic and onions, are the richest sources of organosulfur compounds in the human diet (4). To date, the majority of scientific research relating to the health effects of organosulfur compounds has focused on those derived from garlic. Fresh garlic cloves contain about 2 to 6 mg/g of γ-glutamyl-S-allyl-L-cysteine (0.2%-0.6% fresh weight) and 6 to 14 mg/g of alliin (0.6%-1.4% fresh weight). Garlic cloves yield about 2.5 to 4.5 mg of allicin per gram of fresh weight when crushed. One fresh garlic clove weighs 2 to 4 g (5).

The enzyme alliinase can be inactivated by heat. In one study, microwave cooking of unpeeled, uncrushed garlic totally destroyed alliinase enzyme activity (6). An in vitro study found that prolonged oven heating or boiling (i.e., six minutes or longer) suppressed the inhibitory effect of uncrushed and crushed garlic on platelet aggregation, but crushed garlic retained more anti-aggregatory activity compared to uncrushed garlic (7). Administering raw garlic to rats significantly decreased the amount of DNA damage caused by a chemical carcinogen, but heating uncrushed garlic cloves for 60 seconds in a microwave oven or 45 minutes in a convection oven prior to administration blocked the protective effect of garlic (8). The protective effect of garlic against DNA damage can be partially conserved by crushing garlic and allowing it to stand for 10 minutes prior to microwave heating for 60 seconds or by cutting the tops off garlic cloves and allowing them to stand for 10 minutes before heating in a convection oven. Because organosulfur compounds derived from alliinase-catalyzed reactions may play a role in some of the biological effects of garlic, some scientists recommend that crushed or chopped garlic be allowed to "stand" for at least 10 minutes prior to cooking (6).

Recently, manufactured steel and aluminum have also been used. The wall may have places to attach belay ropes, but may also be used to practise lead climbing or bouldering. Each hole contains a specially formed t-nut to allow modular climbing holds to be screwed onto the wall. With manufactured steel or aluminum walls, an engineered industrial fastener is used to secure climbing holds. The face of the multiplex board climbing surface is covered with textured products including concrete and paint or polyurethane loaded with sand. In addition to the textured surface and hand holds, the wall may contain surface structures such as indentions (incuts) and protrusions (bulges), or take the form of an overhang, underhang or crack. Some grips are formed to mimic the conditions of outdoor rock, including some that are oversized and can have other grips bolted onto them.

References

1. Lawson LD. Garlic: a review of its medicinal effects and indicated active compounds. In: Lawson LD, Bauer R, eds. Phytomedicines of Europe: Chemistry and Biological Activity. Washington, D. C.: American Chemical Society; 1998:177-209
2. Amagase H. Clarifying the real bioactive constituents of garlic. J Nutr. 2006;136(3 Suppl):716S-725S. (PubMed)
3. Trio PZ, You S, He X, He J, Sakao K, Hou DX. Chemopreventive functions and molecular mechanisms of garlic organosulfur compounds. Food Funct. 2014;5(5):833-844. (PubMed)
4. Bianchini F, Vainio H. Allium vegetables and organosulfur compounds: do they help prevent cancer? Environ Health Perspect. 2001;109(9):893-902. (PubMed)
5. Lawson LD. Garlic: a review of its medicinal effects and indicated active compounds. In: Lawson LD, Bauer R, eds. Phytomedicines of Europe: Chemistry and Biological Activity. Washington, D. C.: American Chemical Society; 1998:177-209
6. Song K, Milner JA. The influence of heating on the anticancer properties of garlic. J Nutr. 2001;131(3s):1054S-1057S. (PubMed)
7. Cavagnaro PF, Camargo A, Galmarini CR, Simon PW. Effect of cooking on garlic (Allium sativum L.) antiplatelet activity and thiosulfinates content. J Agric Food Chem. 2007;55(4):1280-1288. (PubMed)
8. Song K, Milner JA. Heating garlic inhibits its ability to suppress 7, 12-dimethylbenz(a)anthracene-induced DNA adduct formation in rat mammary tissue. J Nutr. 1999;129(3):657-661. (PubMed)