Study of furostenol glycoside fraction of Tribulus terresteris on male sexual function in rats

Tribulus terrestris Linn. (Zygophyllaceae) has long been used in the traditional Chinese and Indian systems of medicine for the treatment of various ailments and is popularly claimed to improve sexual function in men. In this study, we have examined the aphrodisiac properties of the furostenol glycoside fraction of Tribulus terrestris extract (TT-FG) in male castrated rats. Adult Wister rats were castrated and divided into five groups of six animals each and treated with either vehicle, sildenafil (5 mg/kg, p.o.) or TT-FG (5, 10, and 25 mg/kg, p.o.) once daily for 14 days. Sexual behavioral and orientational activity was observed after acute (1 day) and subacute (7 and 14 days) treatment. Serum testosterone levels were also measured on day 14 by withdrawing blood from retroorbital plexus. The improvement in sexual behavior as noted by increase in mounting frequency (MF), intromission frequency (IF), and ejaculation latency (EL) and decrease in mounting latency (ML), intromission latency (IL), and postejaculation interval (PEI) after TT-FG treatment in castrated rats in our study implies increase in the desired component of sexuality. TT-FG was found to increase orientational activity parameters such as licking and ano- and genital grooming and decreased climbing and nongential grooming by male rats indicating increased sexual stimulation and lack of interest toward external environment after treatment with TT-FG. These results are supported by increased serum testosterone levels in male rats after 14 days of treatment by TT-FG. In conclusion, the furostenol glycoside fraction of Tribidus terrestris exhibited good aphrodisiac properties.