Two new pyranoxanthones from the stem bark of Calophyllum pseudomolle P.F. Stevens

Two new pyranoxanthones, calotetrapterins D (1) and E (2), were isolated from the stem bark of Calophyllum pseudomolle P.F. Stevens along with α-mangostin (3). The structures of compounds 1-2 were determined based on 1D NMR (¹H, ¹³C) and 2D NMR (HMQC, HMBC), as well as HRESIMS spectroscopic analysis. Compounds 1-2 showed moderate activity against HeLa and murine leukaemia P-388 cells.

Keywords: Calophyllum pseudomolle; Calotetrapterins D and E; cytotoxicity; pyranoxanthones.