Abstract: Column chromatography silical gel and macroporous resin methods were used to isolate and purify the chemical constituents from Ophiorrhiza cantoniensis Hance. Three compounds were isolated from the plant and their chemical structures were identified by physiochemical and spectral method respectively.They were identified as β-sitosterol (1), β-daucosterol (2),vincoside-lactam (3). All of them were isolated from the plant for the first time.In vitro antibacterial activity of the different polar fractions were determined by standard disk diffusion method.Both chloroform extract and petroleum ether extract of this plant had antimicrobial activity.The results indicated that the active antimicrobial compound could be related to β-sitosterol because from the petroleum ether extract we isolated quantities of β-sitosterol (3.2 g).

Key words: Ophiorrhiza cantoniensis, chemical components, vincoside-lactam, anti-bacterial activity