Structures of Mammeasins P and Q, Coumarin-Related Polysubstituted Benzofurans, from the Thai Medicinal Plant (Miq.) T. Anders.: Anti-Proliferative Activity of Coumarin Constituents against Human Prostate Carcinoma Cell Line LNCaP.

A methanol extract of the flowers of (Miq.) T. Anders. (Calophyllaceae) showed anti-proliferative activity against human prostate carcinoma LNCaP cells (IC = 2.0 µg/mL). Two new coumarin-related polysubstituted benzofurans, mammeasins P () and Q (), and a known polysubstituted coumarin mammea B/AC cyclo F () were isolated from the extract along with 44 previously reported polysubstituted coumarin constituents (- and -). The structures of two new compounds ( and ) were determined based on their spectroscopic properties derived from the physicochemical evidence including NMR and MS analyses and taking the plausible generative pathway into account. Among the coumarin constituents, mammeasins A (, IC = 1.2 µM) and B (, 0.63 µM), sugangin B (, 1.5 µM), kayeassamins E (, 3.0 µM) and G (, 3.5 µM), and mammeas E/BA (, 0.88 µM), E/BB (, 0.52 µM), and E/BC (, 0.12 µM) showed relatively potent anti-proliferative activity.