Bioactive Constituents from Radermachera boniana.

Abstract

AbstractThe bioassay‐directed fractionation of the roots of Radermachera boniana Dop. (Bignoniaceae) led to the isolation of 17 naphthalene‐based quinones and related derivatives including the new radermacherones A (1), B (2) and C (6), radermaquinone (3), and radermacherol (5). The absolute configuration of 2 was determined through X‐ray crystallographic analysis. The isolates 3, hydroxy‐β‐isonaphthoquinone (4), 6, α‐naphthoquinone (8), β‐naphthoquinone (9), 3‐hydroxy‐β‐naphthoquinone (10), 4‐oxo‐β‐naphthoquinone (11), 2‐acetyl‐naphtha[2,3‐b]furan‐4,9‐dione (BBI608) (12), 2‐acetyl‐7‐methoxy‐naphtho[2,3‐b]furan‐4,9‐dione(13), stenocarpoquin‐one B (14), dehydro‐α‐isonaphthoquinone (15) and 3‐hydroxydehydro‐α‐isonaphthoquinone (16) showed cytotoxic activity in a cancer cell line panel comprising KB, Col‐2, Lu‐1 and MCF‐7 with IC50 values ranging from 0.15‐38.6 µM. Compounds 12 (known as BBI608) and its methoxy derivative, 13 with extended conjugation showed the highest cytotoxicity among the tested compounds with IC50 values ranging from 0.12‐3.33 µM, but 13 showed much different cancer cell killing selectivity than 12.