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
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).