Comparative evaluation of tamoxifen and red clover extract on reproductive and hepatic function in female Trichogaster trichopterus: a translational endocrine toxicology study.

Tamoxifen, a selective estrogen receptor modulator (SERM), regulates estrogen signaling in a tissue-dependent manner. Phytoestrogens such as red clover (Trifolium pratense) activate estrogenic pathways through receptor agonism and are increasingly studied for hormone-related conditions. This study compared the endocrine and hepatic effects of tamoxifen and red clover extract in a validated vertebrate model, the female three-spot gourami (Trichogaster trichopterus). A total of 120 adult female gourami were randomly assigned to eight groups, receiving intramuscular (IM) injections of tamoxifen (10, 50, 100 mg/kg), IM injections of red clover extract (25, 75, 150 mg/kg), vehicle, or no treatment over 18 days. Reproductive (GSI, hormone levels, ovarian histology) and hepatic (HSI, ALT/AST levels, liver histology, TEM) parameters were assessed. Tamoxifen induced dose-dependent reductions in GSI at 50 and 100 mg/kg (p = 0.004 and p < 0.001), accompanied by significant decreases in sex hormone levels and elevations in ALT and AST (p < 0.01), along with marked hepatic histopathological changes. In contrast, red clover extract significantly increased GSI at 75 and 150 mg/kg (p = 0.012 and p = 0.001) and enhanced sex hormone levels (p < 0.05) compared with controls. Histological and ultrastructural analyses confirmed arrested ovarian development and hepatic degeneration in tamoxifen-treated fish, while red clover-treated fish showed follicular maturation and preserved liver architecture. The contrasting effects of tamoxifen and red clover reflect their distinct estrogen-modulatory mechanisms. While tamoxifen showed anti-estrogenic and hepatotoxic effects, red clover promoted reproductive activity with preserved hepatic safety, supporting its potential as a safer phytoestrogenic alternative.