Aphrodisiac properties of Tribulus terrestris extract (protodioscin) in normal and castrated rats

A. Gauthaman, P.G. Adaikan, R.N. Prasad
National University of Singapore, National University Hospital, Department of Obstetrics and Gynecology, Singapore
Life Sci 2002 Aug 9; 71(12): 1385-96

SUMMARY

Tribulus terrestris (TT) has long been used in traditional Chinese and Indian systems of medicine for the treatment of various ailments and is popularly claimed to improve sexual functions in man. Sexual behavior and intracavernous pressure (ICP) were studied in both normal and castrated rats to further understand the role of TT containing protodioscin (PTN) as an aphrodisiac. Adult Sprague-Dawley rats were divided into five groups of 8 each that included distilled water treated (normal and castrated), testosterone treated (normal and castrated, 10 mg/kg body weight, subcutaneously, bi-weekly) and TT treated (castrated, 5 mg/kg body weight, orally once daily). Decreases in body weight, prostate weight and ICP were observed among the castrated groups of rats compared to the intact group. There was an overall reduction in the sexual behavior parameters in the castrated groups of rats as reflected by decrease in mount and intromission frequencies (MF and IF) and increase in mount, intromission, ejaculation latencies (ML, IL, EL) as well as post-ejaculatory interval (PEI). Compared to the castrated control, treatment of castrated rats (with either testosterone or TT extract) showed increase in prostate weight and ICP that were statistically significant. There was also a mild to moderate improvement of the sexual behavior parameters as evidenced by increase in MF and IFl; decrease in ML, IL and PEI. These results were statistically significant. It is concluded that TT extracts appear to possess aphrodisiac activity probably due to an androgen increasing property of TT (observed in our earlier study on primates).