New clerodane diterpenoids from the roots of Polyalthia laui

Five new clerodane diterpenoids, polylauiester A (1), (4 → 2)-abeo-2,13-diformyl-cleroda-2,12E-dien-14-oic acid (2) and polylauiamides B–D (3–5), together with 11 known clerodane diterpenoids (6–16), were isolated from the roots of Polyalthia laui. Among them, polylauiester A (1) represents the first example of a novel norclerodane diterpenoid only containing 17 carbon atoms on the carbon skeleton, and polylauiamide B (3) is an unusual diterpenoid with a p-substituted benzene ring as a substituent. Their structures were elucidated by extensive spectroscopic methods, and the relative configuration of polylauiamide B (3) was further confirmed by the single crystal X-ray diffraction method. Biological evaluation of new compounds against human Hela, MCF-7 and A549 human cancer cell lines showed that all compounds displayed weak cytotoxicities against various human cancer cell lines in the range of IC50 at 25.01–39.31 μM.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image ( K)Download as PowerPoint slide