Two new coumarins from Micromelum falcatum with cytotoxicity and brine shrimp larvae toxicity.

Two new coumarins, 7-methoxy-8-(2-hydroxmethyl-1-O-isovaleryl-4-butenyl)coumarin (1) and 7-methoxy-8-(1-hydroxy-2-O-beta-glucopyranosyl-3-methyl-4-butene-1-yl) coumarin (2), and twelve known coumarins 3-14 were isolated from the stem bark of Micromelum falcatum. The structures of compounds 1-14 were elucidated by extensive spectroscopic data analyses. The toxicity of compounds 1-14 was tested using a brine shrimp assay and in vitro antiproliferative assay against mammary cancer (F10) and lung cancer (HvEvc) cell lines by the MTT method. Some compounds had moderate activities. All compounds were also tested against the microorganisms Bacillus subtilis, Bacillus thuringiensis and Escherichia coli, but no activity was observed.