Calofolic acids A–F, chromanones from the bark of Calophyllum scriblitifolium with vasorelaxation activity

Vasorelaxation activity guided separation of the methanol extract of Calophyllum scriblitifolium bark led to the isolation of 6 chromanones (calofolic acids A-F, 1-6). 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. All isolated chromanones showed dose-dependent vasorelaxation activity on isolated rat aorta.