Cytotoxic triterpenoids and steroids from the bark of Melia azedarach

Abstract

Two new triterpenoids (1, 2) and two new steroids (3, 4) along with twelve related known compounds (5-16) were isolated from the bark of Melia azedarach. The new structures were elucidated by means of spectroscopic methods and molecular modeling studies and found to be 21,24-cycloeupha-7-ene-3β, 16β,21α,25-tetrol (1), 3β-acetoxy-12β-hydroxy-eupha-7,24- dien-21,16β-olide (2), 29-hydroperoxy-stigmasta-7,24(28)E-dien-3β-ol (3), and 24ξ-hydroperoxy-24-vinyl-lathosterol (4). All isolated compounds were tested for their cytotoxic activity against three human cancer cell lines (A549, H460, HGC27) using the CellTiter Glo™ luminescent cell viability assay. Among them, compounds 2-4, 24ξ-hydroperoxy-24-vinyl-cholesterol (6), kulinone (7), meliastatin 3 (8), 3-oxo-olean-12-en-28-oic acid (10), and (22E,24S)-5α,8α-epidioxy-24-methyl-cholesta-6,22-dien-3β-ol (12) were found to have cytotoxic effects, with IC50 values of 5.6-21.2μg/mL. © Georg Thieme Verlag KG Stuttgart.