Objective: To study the chemical constituents from Oldenlandia diffusa . Method: The compounds were isolated and purified by column chromatography on silica gel

MCI gel

Sephadex LH-20 and RP-semi-preparative HPLC. The structures of compounds were elucidated on the basis of physicochemical and spectral analysis. Result: Six compounds were isolated from the water extract of O. diffusa

and their structures were identified as 2'-deoxythymidine (1)

2'-O-methyl-inosine (2)

inosine (3)

uridine (4)

guanosine (5)

β-adenosine (6)

respectively. Conclusion: All the isolated compounds were obtained from the Hedyotis for the first time.