Background Limited male contraception choices have prompted the hunt for natural antifertility drugs. This experimental study investigates the antifertility effects of stigmasterol extracted from Pluchea indica leaves in male rats (Rattus norvegicus). Because reproductive hormones were not directly measured, mechanistic interpretations related to testosterone, luteinizing hormone, and follicle-stimulating hormone are presented as possible explanations rather than confirmed endocrine effects. Methods This was a randomized experimental study involving twenty-four male rats, which were randomly allocated into four groups (n = 6/group): one control group and three treatment groups receiving stigmasterol at 0.25, 0.5, and 0.75 mg/kg body weight orally for 45 days. Histological examination of testicular tissue and evaluation of sperm morphology were performed to assess spermatogenic activity. Epididymal spermatozoa were collected after euthanasia, diluted, stained with eosin, and evaluated microscopically using standardized morphological criteria. To elucidate possible molecular mechanisms, an in silico network pharmacology analysis was conducted using SEA, CTD, DAVID, STRING, and Cytoscape platforms. Results A significant reduction in spermatogenic cell counts and increased sperm morphological abnormalities were observed, particularly at the highest dose (0.75 mg/kg BW) (p = 0.043). Network pharmacology analysis identified 76 predicted protein targets related to spermatogenesis, hormonal regulation, and inflammation, including EGFR, IL6, TNF, ESR1, and AKT1. Conclusions This experimental study demonstrates that stigmasterol from P. indica leaves, particularly at 0.75 mg/kg BW, exerts antifertility effects by reducing spermatogenic cells and inducing sperm abnormalities in male rats. However, because fertility trials, reversibility assessment, reproductive hormone assays, and comprehensive systemic toxicity evaluation were not conducted, these findings should be interpreted as preliminary preclinical evidence requiring further validation.
