[Studies on chemical constituents of two plants from Costus].

To study the chemical constituents of Costus speciosus and C. tonkinensis (Zingiberaceae) distributed in Yunnan province. Chromatography and spectral analyses were used to isolate the constituents and elucidate their structure. Six compounds were isolated from the rhizome of C. speciosus and elucidated as diosgenin(1), prosapogenin B of dioscin(2), diosgenone(3), cycloartanol(4), 25-en-cycloartenol(5) and octacosanoic acid(6). Four compounds were isolated from the rhizome of Costus tonkinensis and elucidated as tetracosanoic acid(7), succinic acid(8), beta-sitosterol(9) and daucosterin(10). Compounds of 3-6 were obtained from C. speciosus for the first time and compounds of 7-10 were obtained from C. tonkinensis for the first time too.