Ethanolic extract of Mill. (Lauraceae) seeds induced antiestrogenic effects in young female Wistar rats.

Objectives: The ethanol extract of seeds was found to inhibit the development of estrogen-dependent conditions in female Wistar rats, suggesting the ability of its secondary metabolites to interact with estrogen receptors (ERs), either as partial agonists or as antagonists. To test this hypothesis, the abovementioned extract was assessed for its ability to mimic and/or antagonize estradiol effects.

Methods: Two experiments were conducted in ovariectomized (OVX) rats: (1) animals were treated with estradiol valerate (EV; 1 mg/kg) or at doses of 25 and 50 mg/kg; (2) animals were treated with EV alone (0.75 mg/kg) or in combination with at the abovementioned doses. Treatments were given orally for 3 days and animals were sacrificed for biochemical and histological analyses of the uterus and vagina.

Results: When administered alone, did not change the histomorphology of both organs (uterus and vagina). In combination with EV, decreased uterine weight [30 % decrease (p<0.001) at 25 mg/kg and 24 % (p<0.01) at 50 mg/kg] and epithelium height (37 % decrease). This was associated with decreased estradiol levels (at least 86 % decrease, p<0.001) in the uterus. Similarly, vagina epithelium height decreased by at least 34 % (p<0.05) when EV was co-administered with .

Conclusions: The seed extract of contains ER antagonist secondary metabolites accounting for its ability to inhibit the development of estrogen-dependent conditions in female rats.