Three new ent-kaurane diterpenes from the herbs of Wedelia prostrata

Three new ent-kaurane diterpenes, 3α-angeloyloxy-17-hydroxy-ent-kaur-15-en-19-oic acid (1), 3α-tigloyloxy-17-hydroxy-ent-kaur-15-en-19-oic acid (2) and 3α-cinnamoyloxykaur-9(11),16-dien-19-oic acid (3), along with five known compounds (4-8), were isolated from the herbs of Wedelia prostrata (Asteraceae). The structures were determined by extensive analysis of their spectroscopic data (IR, UV, HRESIMS, 1D and 2D NMR). The isolated compounds were evaluated for their cytotoxic activity on human hepatocellular carcinoma HepG2 cells. Among them, all isolates exhibited cytotoxic activities with IC₅₀ values ranging from 9.55 ± 0.45 to 53.92 ± 1.22 μM.