Abstract: “Since, there is only few documented evidence referring to assessment of the clear specific actions of medicinal plant source or active constituents in rodent model, the present study is undertaken to evaluate the effective concentration of technical azadirachtin-A, a tetranortritarpinoid of neem seed kernel, to immobilizes the cauda epididymal spermatozoa within 20 seconds and effectively inhibits sperm motility, viability and plasma membrane integrity in a dose-dependent manner. Spermicidal efficacy was evaluated in vitro by a modified Sander–Cramer test using different concentrations. The mode of spermicidal action was evaluated by (a) Sperm morphology and viability tests (b) hypo-osmotic swelling (HOS) tests and (c) transmission electron microscopy. The minimum effective concentration (MEC) of azadirachtin-A for 100 % immobilization of sperm in 20 secs was around 4.50µg/million sperm. No morphological changes were found in the sperm head, midpiece or tail and no viable sperm seen. F”

Keywords: Azadirachtin-A, spermatozoa, MEC, HOS and rat