Testicular 5 alpha reductase (type 2) expression and dihydrotestosterone (DHT) hormone level in male sprague-dawley rats treated with eurycoma longifolia and polyalthia bullata

An aqueous extract of Eurycoma longifolia (EL) or known as Tong/wt Ali roots is traditionally used as natural alternative for testosterone replacement therapy and has been proven to increase serum testosterone level. Polyalthia bullata (PB), or also known known as Tongkat Ali Hitam had been consumed widely as people assuming it has aphrodisiac property because it shares the same name as Tongkat Ali. Because previous studies are limited to only on testosterone concentration, this study investigated the in vivo effects of both EL and PB on body and reproductive organ weight, DHT concentration as well as 5a reductase expression in healthy male Sprague-Dawley rats. Twenty-four male rats were divided into a control (n=8), EL 800mg/kg group (n=8), and PB 800mg/kg (n=8). The control group was given distilled water. Rats were force fed for 14 days and sacrificed 24 hours after the last treatment. Total body and reproductive organs (testes, epididymis, prostate and seminal vesicle) weight were recorded. Moreover, DHT concentration level was determined by using enzyme-linked immunosorbent assay (ELISA) method using the blood serum from the rats. The gene expression of 5 alpha reductase was carried out by Real-time PCR and measured by relative quantitation method (2^-∆∆Ct). PB significantly decreased the body weight of the rats (p<0.05) while there were no significant changes in weight of the reproductive organs between all the experimental groups. DHT concentration in the rats showed significantly increased for both EL and PB compared to control (p = 0.027, p = 0.040). Gene expression of Sa reductase showed an upregulation trend by 0.86 fold for EL group but yet not significantly.