Role of garlic (Allium sativum L.) in human and plant diseases.

A resurgence of interest in garlic due to recent revelations of its beneficial effects in the treatment of various human and plant diseases and also due to validation of claims made in traditional systems of medicine has resulted a plethora of publications on different aspects of garlic in recent years. Chemical constituents of garlic and their variations on the methods of isolation have been discussed in the present review. Effect of garlic and its constituents against various human and plant pathogenic and saprophytic microorganisms has also been reviewed.

Antiulcer activity of naturally occurring pyrano-coumarin and isocoumarins and their effect on prostanoid synthesis using human colonic mucosa.

Oral administration of bergenin and norbergenin, two isocoumarins, isolated from the leaves and roots of Flueggea microcarpa and luvangetin, a pyranocoumarin isolated from the seeds of Aegle marmelos Correa, showed significant protection against pylorus-ligated and aspirin-induced gastric ulcers in rats and cold restraint stress-induced gastric ulcers in rats and guinea pigs. The study on prostaglandins release by human colonic mucosal incubates, indicated a concentration-dependent (1-10 micrograms/ml) stimulatory effect of bergenin and norbergenin, while luvangetin (1-10 micrograms/ml) did not produce any effect. The results suggest that gastroprotective effects of bergenin and norbergenin could be due to increased prostaglandin production while, some other mucosal defensive factors may be involved for luvangetin.

Effect of withafastuosin E on gastric mucosal offensive and defensive factors in rats.

Withafastuosin E (WE), a withanolide of Datura fastuosa, has been reported to possess anti-stress activity and augment prostaglandins. The present investigation has been undertaken to evaluate the anti-ulcer activity and its mechanism in various models of experimentally induced ulcers in rats. WE (20 mg/kg, po) reduced the incidence of ulcer and ulcer index significantly in rats. The drug also decreased volume of gastric secretion, acid and peptic output, though it did not affect mucin secretion or mucosal glycoprotein content in terms of total carbohydrate:protein ratio or gastric cell shedding (in terms of gastric juice DNA content) or cell replication (in terms of microgram DNA/mg of protein). The results suggest significant anti-ulcer activity of WE which may be due to its effect on decreasing the offensive acid-pepsin factors.