Cytotoxic limonoids and tetranortriterpenoids from Melia azedarach.

The ethanolic extract of the root bark of Melia azedarach exhibited cytotoxic activity against lymphocytic leukemia P388 cell lines in vitro. Systematic fractionation of the extract monitored by cytotoxic bioassay led to the isolation of two new azadirachtin-type limonoids, 1-tigloyl-3-acetyl-11-methoxymeliacarpinin (1) and 1-acetyl-3-tigloyl-11-methoxymeliacarpinin (2), together with three highly cytotoxic sendanin-type limonoids, 29-isobutylsendanin (3), 12-hydroxyamoorastin (4) and 29-deacetylsendanin (5). The acetylated derivatives of 4 also underwent cytotoxic bioassay.