SPERMICIDAL ACTIVITY OF MAGAININS - IN-VITRO AND IN-VIVO STUDIES

Spermicidal efficacy of two synthetic antimicrobial peptides, viz. Mag ainin-A (Mag-A) and Magainin-G (Mag-G), have been studied under in vit ro condition using rat and human spermatozoa. The data showed that spe rm motility was inhibited with various concentrations of Magainins at different intervals ranging from 20 to 480 seconds as compared to cont rols. The minimum concentration of Mag-A required to immobilize sperma tozoa (40-60 x 10(6)/ml of saline) within 20 seconds was found to be 1 00 mu g in rat and 200 mu g in human. The action of Mags on sperm moti lity was observed to be dose-dependent. The activity of Mag-A was sign ificantly (P < 0.05) higher than Mag-G (P < 0.05). The in vivo studies in rats indicated that Mag-A when applied intravaginally, on the day of estrus, at the dose level of 200 pg, for five consecutive estrous c ycles, induced no abnormalities either in the length of estrous cycle or in morphology of vaginal epithelial cells. When Mag-A was applied i ntravaginally before mating on the proestrus-estrus day, complete arre st of sperm motility with 200 mu g concentration was observed and none of these treated females conceived after the mating. In view of these facts, it is suggested that Mag-A, having anti-bacterial, anti-viral, anti-fungal and spermicidal activities, could be a potent vaginal con traceptive.