Antifertility effect of Citrus hystrix DC

An alcohol and chloroform extract of Citrus hystrix DC. fruit peel was investigated for antifertility activity in pregnant rats by oral administration at different periods of gestation. The extracts were found to effectively inhibit implantation, produce abortion and slightly hasten labor time when it was given from day 2 to 5, day 8 to 12 and day 15 until labor, respectively. At the same dose level which interrupted pregnancy, the extract did not affect the estrous cycle. Neither uterotrophic effects nor induction of vaginal cornification was observed when it was given to spayed rats. However, the extract enhanced the uterotrophic effect of estradiol when both were simultaneously given. Additionally, the extract stimulated uterine contractions observed in an in situ study. It is suggested that these two effects may be responsible for the interruption of pregnancy associated with the extract.