Triterpenoids and Limonoids from Dysoxylum lukii with Cytotoxic and Antimicrobial Activities

A phytochemical investigation of a 70?% ethanol extract of the stem bark of Dysoxylum lukii has resulted in the isolation of eight new tirucallane-type triterpenoids, one new limonoid, and five known compounds. Their structures have been elucidated on the basis of extensive 1D and 2D NMR (COSY, HMQC, HMBC and NOESY) analyses. The cytotoxic and antimicrobial properties of the isolated compounds were evaluated in vitro. Compounds 6 and 10 exhibited significant cytotoxic activity against all tested cell lines with IC50 values of 6.6410.55 and 8.9012.08 mu M, respectively. Furthermore, compounds 6, 7, 8, 10, and 11 exhibited potent antimicrobial activity against all the Gram-positive and Gram-negative bacteria tested.