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To be fair, I will also include some more serious medical research into the Alliums for a well-rounded discussion: (read entry below first to see where this discussion started.)
"There are more than 250 members of the genus Allium, the onion family. Two of these, onions (A. cepa), and garlic (A. sativum), have been used in traditional and folk medicine for over 4,000 years. Disorders for which both garlic and onions have been used include: asthma, arthritis, arteriosclerosis, chicken pox, the common cold, diabetes, malaria, tumors, and heart problems. Modern science has shown that alliums and their constituents have several therapeutic effects including: antiplatelet aggregation activity, fibrinolytic activity, anticarcinogenic effects, antimicrobial activity, and anti-inflammatory and anti-asthmatic effects.
Volatile sulfur compounds are not present as such in intact cells. The reaction between the enzyme allinase and the volatile precursors [S-alk(en)yl cysteine sulfoxide and sulfonic acid] takes place when cells are ruptured, resulting in the formation of different thiosulfinates and related sulfonic-acid derived compounds. Decomposition of thiosulfinates such as allicin (diallyl thiosulfinate) proceeds by several pathways.
One interesting pathway involves three molecules of allicin which combine, producing two molecules of ajoene which is apparently at least as potent as aspirin in preventing the aggregation of blood platelets and thus in keeping blood from clotting. Through other non-enzymatic degradation pathways, thiosulfonates are converted into sulfur-containing compounds such as thiosulfinates, cepaenes, mono-, di- tri- and tetrasulfides, thiols, thiophenes, and sulfur dioxide. The types and concentrations of sulfur compounds extracted from onions and garlic are affected by plant maturity, production practices, cultivar, location in the plant, and processing conditions. Other bioactives present in garlic and onion include: flavonoids, prostaglandins, sterols and steroid saponins, and oligofructans.
Flavonoids are present in the bulbs as well as the leaves of alliums. The flavonoids found in onion include eight quercetin glucosides, the 4’-glucoside, the 7,4’-diglucoside, the 3-4’-diglucoside, the 3-glucoside, the 7-glucoside, the 3,7-diglucoside, the 3-rutinoside (rutin), the 3-rhamnoside (quercitrin), the 7,4’-, and 3-glucosides of kaempferol, isorhamnetin 4’-glucoside, and eight anthocyanins. Most of these flavonoids are potent antioxidants and have a wide array of biochemical functions. They are involved in immune function, gene expression, capillary and cerebral blood flow, liver function, enzyme activity, platelet aggregation, and collagen, phospholipid, cholesterol and histamine metabolism.
Sterols and steroidal glycosides have been found in various alliums and saponin levels of 0.1% in leek, 0.021% in garlic and 0.095% in onion have been reported . The content of sterols and their glycosides have been determined in leaves and bulbs of onion, and levels of 2.7% free sterols and sterol esters, 1.7% sterol glycosides and 0.8% acetyl sterol glycosides in leaves have been reported. In bulbs, the amount of these sterol derivatives is lower than in leaves.
Onion bulbs contain a high concentration (35-40% dry wt) of fructans, which constitute a major portion of the water-soluble carbohydrates, and have been associated with storage life of bulbs. Fructans are fructosyl polymers which consist of linear chains of D-fructose molecules joined by linkages. This chain is terminated by a D-glucose molecule linked to fructose by an bond as in sucrose.
A number of health benefits result from ingestion of oligofructans or oligosaccharides. These include: proliferation of bifidobacteria and reduction of detrimental bacteria in the colon, reduction of toxic metabolites and detrimental enzymes, prevention of constipation, protection of liver function, reduction of serum cholesterol, reduction of blood pressure, and anticancer effects."
Selected References
Mazza, G. (Ed). 1998. Functional Foods, Biochemical and Processing Aspects. Technomic Publ. Co. Inc., Lancaster, Pa
Posted by Kurma on 9/8/05; 7:35:12 AM
from the Travel dept.
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