Postcoital interceptive activity of Wrightia tinctoria in Sprague-Dawley rats:: a preliminary study

Background: This study was aimed to investigate the pregnancy-interceptive activity of the stein bark OF Wrightia tinctoria R.Br. (Family Apocynaceae) administered during the preimplantation, peri-implantation and early postimplantation periods by oral route in adult female Sprague-Dawley rats. Study Design: The ethanolic extract of the stein bark and its serial fractions were administered to female rats on Days 1-7 or 1-5 postcoitum (Day 1: day of sperm-positive vaginal smear) by the oral route. At autopsy on Day 10 postcoitum, the number and status of corpora lutea and implantations were recorded. For estrogen-agonistic activity, immature rats ovariectomized 7 days earlier received the test extract or the vehicle once daily for 3 (lays and, at autopsy on Day 4 uterine weight, status of vaginal opening and extent of vaginal cornification were recorded. Results: The ethanolic extract of the stern bark of W. tinctoria R.Br. inhibited pregnancy in 100% of rats when administered orally at a 250-mg/kg dose on Days 1-7 or 1-5 postcoitum. On fractionation, the hexane-soluble, chloroform-soluble, water-soluble and water-insoluble fractions showed 100% anti-implantation effect. while n-butanol-soluble fraction intercepted pregnancy in 75% of animals when administered in the Days 1-5 postcoitum schedule. In immature rat bioassay, the active ethanolic extract and its fractions exhibited moderate to potent estrogen-agonistic activity, which might be responsible for their contraceptive action in this species. Conclusions: Findings demonstrate the antifertility activity of the ethanolic extract of the stein bark of W tinctoria and its hexane-soluble, chloroform-soluble. water-soluble and water-insoluble fractions. Studies that pursue promising natural products (to identify contraceptive agents from natural sources lacking potent estrogenic activity) towards a fruitful conclusion for development/lead generation should continue. (C) 2008 Elsevier Inc. All rights reserved.