Sexual effect's of puncturevine (Tribulus terrestris) extract (protodioscin):: An evaluation using a rat model

Objective: Apart from its claims for improvement of sexual functions in men, the puncturevine plant (Tribulus terrestris: TT) has long been considered as an energizer and vitalizer in the indigenous system of medicine. Sexual behavior and intracavernous pressure. (ICP) measurements were taken in rats to scientifically validate the claim of TT [containing protodioscin (PTN)] as an aphrodisiac. Materials and methods: Forty sexually mature male Sprague-Dawley rats were randomly divided into four groups of 10 each. Group I served as a control group and groups II, III, and IV were treated with three different doses of TT extract (2.5, 5 and 10 mg/kg body weight, respectively), orally, once daily for 8 weeks. Weight was recorded and the rats from all four groups were subjected to sexual behavior studies with primed females and various parameters namely mount and intromission frequencies (MF and IF, respectively), mount, intromission and ejaculation latencies (ML, IL, and EL, respectively) as well as postejaculatory interval (PEI) were recorded. In addition, blood pressure and ICP were recorded for all rats at the end of study. Results: Increases in body weight (by 9, 23, and 18% for groups II, III & IV) and ICP (by 43% and 26% for groups III and IV) were statistically significant compared to the control group. Increases in MF (by 27% and 24%) and IF (by 19% and 22%) for the groups III and IV were statistically significant. Decreases in ML (by 16%, 23%, and 22% for groups II, III, and IV) and PEI (by 20% for group III) were statistically significant compared to the control. Conclusions: The weight gain and improvement in sexual behavior parameters observed in rats could be secondary to the androgen increasing property of TT (PTN) that was observed in our earlier study on primates. The increase in ICP which confirms the proerectile aphrodisiac property of TT could possibly be the result of an increase in androgen and subsequent release of nitric oxide from the nerve endings innervating the corpus cavernosum.