Caloforines A–G, coumarins from the bark of Calophyllum scriblitifolium

Abstract

Bioactivity-guided separation of the methanol extract of Calophyllum scriblitifolium bark led to the isolation of five new pyranocoumarins, caloforines A–E (1–5) and two new coumarins, caloforines F and G (6 and 7). Their structures were elucidated by 1D and 2D NMR spectroscopy, and their absolute configurations were investigated by a combination of CD spectroscopy and DFT calculation. Caloforines A–F (1–6) showed moderate antimalarial activity against Plasmodium falciparum 3D7 strain. Graphical abstract: [Figure not available: see fulltext.]