Homoisoflavanones from Disporopsis aspera

Abstract From cytotoxic extracts of the roots of Disporopsis aspera Engl. (Liliaceae) a homoisoflavanone, disporopsin (3-(2′,4′-dihydroxy-benzyl)-5,7-dihydroxy-chroman-4-one) ( 1 ) and three rare methyl-homoisoflavanones, 3-(4′-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-chroman-4-one ( 2 ), 3-(4′-hydroxy-benzyl)-5,7-dihydroxy-6,8-dimethyl-chroman-4-one ( 3 ) and 3-(4′-hydroxy-benzyl)-5,7-dihydroxy-6-methyl-8-methoxy-chroman-4- one ( 4 ) along with five other known compounds, N - trans -feruloyl tyramine ( 5 ), adenine ( 6 ), 5-(hydroxymethyl)-2-furfural ( 7 ), β -sitosterol ( 8 ) and β -sitosteryl glucopyranoside ( 9 ) were isolated. The structures of compounds 1 – 2 were elucidated by spectral data (1, 2-D NMR and EIMS). The four homoisoflavanones ( 1 – 4 ) were found to be cytotoxic against a series of human cancer cell lines (HCT15, T24S, MCF7, Bowes, A549 and K562) with IC 50 ranging from 15 to 200 μM. Possible biosynthesis routes for homoisoflavonoids ( 1 – 4 ) are discussed.