Antifertility activity of plumbagin.

Abstract

The antifertility effects of plumbagin (2-methyl-5 hydroxy1-4 napthoquinone) are reevaluated and the chemical structure is illustrated. Plumbagin is a crystalline substance extracted from Plumbago zeylanica and other plants belonging to the Plumbaginacea family. These plants grow in south India as perennial herbs. Plumbagin had been reported to be an irritant to the smooth muscle of the uterus. Plumbagin was suspended in .5% of gum acacia in water or in propylene glycol and given orally through a stomach tube in a volume of 1 ml/100 gm of body weight. Controls received only the .5% gum acacia. Plumbagin given for 15 days before cohabitation and 15 days during cohabitation inhibited mating in 62.5% of rats. The treated females did not mate for 10-12 days after withdrawal of the drug. The estrous cycles and diestrous phase of rats were significantly (pe.005) prolonged in treated animals. With doses of .5-2 mg/100 gm of body weight abortions were caused increasing with frequency as the dose was increased. Acute toxic symptoms were not observed with doses of .25-2 mg/100 gm of body weight but with 4 and 8 mg a 50% mortality rate was found. Even though plumbagin is an effective antifertility agent its margin of safety was low in rats mice and rabbits. In rats the LD50 effect was seen with 4-6.5 mg/100 mg of body weight when given orally. Antifertility effects were found with doses of 1 mg/100 gm of body weight.