A new pentacyclic triterpenoid,urs-12-en-29α-oic acid-3β-ol (1),was obtained from the ethanol extract of Chinese herb Oldenlandia cantonensis How.The structure was elucidated by spectroscopy methods,including nuclear magnetic resonance (NMR) (ID and 2D),infrared spectroscopy (IR),and mass spectrometry (MS).1 exhibited significant inhibitory activity against the human DNA topoisomerase Ⅰ (hTopo Ⅰ),the cancer cell lines BEL-7402 and MCG-803,with the IC50 values 12.0,6.5,and 8.0 μg/mL,respectively.The volatile oil,the fraction of petroleum ether:EtOAc = 20:1 (V/V) on Si gel chromatography,was also quantitatively analyzed by gas chromatography mass spectrometry (GC-MS).As a result,60 compounds were identified.Among them,the long chain aliphatics,terpenes and steroids,as the representative structure type,were found with percentages of 36.16%,6.42% and 9.28%,respectively.
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