Cytotoxic triterpenoids and steroids from the bark of Melia azedarach

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-3 β,16 β,21 α,25-tetrol (1), 3 β-acetoxy-12 β-hydroxy-eupha-7,24-dien-21,16 β-olide (2), 29-hydroperoxy-stigmasta-7,24(28) E-dien-3 β-ol (3), and 24 ξ-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, 24 ξ-hydroperoxy-24-vinyl-cholesterol (6), kulinone (7), meliastatin 3 ( 8), 3-oxo-olean-12-en-28-oic acid (10), and (22 E,24 S)-5 α,8 α-epidioxy-24-methyl-cholesta-6,22-dien-3 β-ol (12) were found to have cytotoxic effects, with IC?? values of 5.6-21.2?μg/mL.