Determination of possible contraceptive potential of methanolic leaf extract of Mentha longifolia L. in adult male rats: a biochemical and histological study

Mentha longifolia L (ML) is locally used as an herbal contraceptive. We aim to assess the toxicity profile and validate the antifertility effects of its leaves in male rats. Adult male Sprague Dawley rats (n = 10 animals/group) were divided into four groups. The Control group received .9% saline, while groups II, III, and IV received 50, 75, and 100 mg/kg/day ML doses for 28 days. ML induced a dose-dependent decrease in percent fertility as well as the number of pups born in ML preexposed pairs, with maximum change observed in the ML3 group (60%, 3.75 +/- 1.25) as compared to control (100%, 8.75 +/- .48) group. A significant (P < .01) decrease in the rate of daily sperm production was observed in the ML3 group (.86 +/- .16) in contrast to the control (2.93 +/- .05). The levels of catalase and superoxide dismutase declined significantly in treatment groups (ML1-P < .001, ML2-P < .05, and ML3-P < .01). A significant increase in the production of reactive oxygen species (P < .001) was found in all treatment groups. The concentrations of LH (P < .001), FSH (P < .001), and testosterone (P < .001) were significantly reduced in a dose-dependent manner among ML-treated groups. Decreases in spermatogonial populations, mature spermatids, seminiferous tubule diameter, lumen diameter, and epithelial height were noticed at higher doses. The reversibility study depicted a reduction in both pregnancy outcomes and litter size. Besides contraceptive effects, M. longifolia L usage is associated with oxidative stress; therefore, it is important to consume this herb appropriately and its excessive usage should be prohibited.