Rakanmakilactones A–F, new cytotoxic sulfur-containing norditerpene dilactones from leaves of Podocarpus macrophyllus var. maki

Abstract

Six new S-containing norditerpene dilactones, rakanmakilactones A–F ( 5– 10 ), were isolated from the leaves of Podocarpus macrophyllus D. Don var. maki Endl., along with four known norditerpene dilactones ( 1– 4 ). Their structures, stereochemistry and absolute configurations were determined by spectroscopic studies (HRMS, IR, 1H, 13C and 2D NMR), and single-crystal X-ray analyses. Rakanmakilactones were found to have a cytotoxic effect against P388 murine leukemia cells.