Antimicrobial arylcoumarins from Asphodelus microcarpus.

A new aryl coumarin glucoside, asphodelin A 4'-O-beta-d-glucoside (1), and its aglycon, asphodelin A (2), were isolated from Asphodelus microcarpus. The structures were determined by detailed spectroscopic analysis and chemical transformation as 3-(2'-hydroxy-p-O-beta-d-glucopyranosyloxyphenyl)-4,7-dihydroxy-2H-1-benzopyran-2-one (1) and 3-(2',4'-dihydroxyphenyl)-4,7-dihydroxy-2H-1-benzopyran-2-one (2), respectively. These compounds were isolated following bioactivity-directed fractionation, using antimicrobial activity, in which 1 and 2 exhibited moderate and potent activities, respectively. This is the first report of a 3-arylcoumarin derivative, a rare class of isoflavonoids, from a plant in the family Liliaceae.