New diterpenoids from the stems of <i>Euphorbia antiquorum</i> growing in Vietnam
Thanh-Nha Tran, Jirapast Sichaem, Van‐Kieu Nguyen, Huu‐Hung Nguyen, Truong-Tam Cao, Thi-Phuong Nguyen, Vo Van Giau, Nakorn Niamnont, Ngoc‐Hong Nguyen, Thuc‐Huy Duong
Abstract
Phytochemical analysis of Euphorbia antiquorum stem extracts afforded two new ent-atisane compounds, ent-3α-acetoxy-16β,17,18-trihydroxyatisane (1) and ent-3α,14,16β,17-tetrahydroxyatisane (2) together with three known compounds, 20-deoxy-16-hydroxyingenol (3), ent-14[S],16α,17-trihydroxyatisan-3-one (4), and agallochaol C (5). Their structures were elucidated by spectroscopic data analysis and comparison with published NMR data. Compounds 1–5 were evaluated for α-glucosidase inhibition and cytotoxicity. Compounds 1, 4, and 5 revealed significant inhibitory activity against α-glucosidase with the IC50 values of 119.9, 135.5, and 134.3 µM, respectively. None showed activity in cytotoxicity assay.