New diterpenoids from the stems of growing in Vietnam.

Phytochemical analysis of stem extracts afforded two new atisane compounds, 3-acetoxy-16,17,18-trihydroxyatisane () and 3,14,16,17-tetrahydroxyatisane () together with three known compounds, 20-deoxy-16-hydroxyingenol (), 14[S],16,17-trihydroxyatisan-3-one (), and agallochaol C (). Their structures were elucidated by spectroscopic data analysis and comparison with published NMR data. Compounds were evaluated for -glucosidase inhibition and cytotoxicity. Compounds , , and revealed significant inhibitory activity against glucosidase with the IC values of 119.9, 135.5, and 134.3 µM, respectively. None showed activity in cytotoxicity assay.