| Using natural product is now in trend. As a result, people turn attention to use more herbs. Vegetables and herbal consumption with modern medicines may result in herb-drug interaction. This research aimed to study the effect of Azadirachta indica, and the other 4 herbal extracts onto the function of the CYP3A4 enzyme. Metabolic reaction, testosterone 6-β hydroxylation, was carried out in vitro then measured the amount of 6-β hydroxytestosterone, major metabolite of testosterone by HPLC. The percentage inhibition of the enzyme CYP 3A4 was calculated from amount of metabolite detected. The results showed that in aqueous extracts a percentage of inhibition of the enzyme CYP 3A4 in Azadirachta indica, Eurycoma harmandiana, Eurycoma longifolia, Tinospora crispa and Oroxylum indicum are as following; 81.13%, 15.44%, 20.20%, 4.72% and 20.49% respectively. From the methanol extracts, percentage of inhibition of the CYP3A4 enzyme in Azadirachta indica, Eurycoma harmandiana, Eurycoma longifolia, Tinospora crispa and Oroxylum indicum are as following; 37.87%, 22.12%, 3.78%, 14.01% and 26.88% respectively. Lastly from the hexane extracts, percentage of inhibition of the CYP3A4 enzyme in Azadirachta indica, Eurycoma harmandiana, Eurycoma longifolia, Tinospora crispa and Oroxylum indicum are as following; 24.34%, 23.14%, 29.10%, 0.19% and 1.21% respectively. In addition, the ethyl acetate extracts percentage of inhibition of the CYP3A4 enzyme in Eurycoma harmandiana and Eurycoma longifolia are 32.82% and 1.25%. We can conclude that the different herbs and different solvent extracts provide different inhibitory effect to the CYP3A4 enzyme. |