Low doses of diallyl disulfide, a compound derived from garlic, increase tissue activities of quinone reductase and glutathione transferase in the gastrointestinal tract of the rat

Diallyl disulfide (DADS), a substance that is formed form the organosulfur compounds present in garlic is known to increase tissue activities of the phase II detoxification enzymes quinone reductase (QR) and glutathione transferase (GT) in animals. In previous experiments, however, high doses of DADS were employed and only a limited range of tissues were examined. In the present studies, increased activities of QR and GT were recorded in the forestomach, glandular stomach, duodenum, jejunum, ileum, cecum, colon, liver, kidneys, spleen heart, lungs, and urinary bladder of mts given DADS over a wide range of dose levels. Large variations in response were recorded among the different organs, with forestomach, duodenum, and jejunum being the most sensitive to enzyme induction by DADS. In these organs, significant increases in QR activity were observed at a dose of only 0.3 mg/kg/day. Such a dose level is close to that which may be achieved through human consumption of garlic, suggesting that indiction of phase II enzymes may contribute to the protection that is afforded by this vegetable against cancer of the gastrointestinal tract in humans.