Isolation of terpenoid from Alstonia Spathulata and Kopsia Singapurensis (Apocynaceae)

The aim of this study was to extract and identify the chemical compounds isolated from Alstonia spathulata and Kopsia singapurensis. The isolated compounds were tested for their biological activities include cytotoxicity (MCF-7 cell line), antibacterial (Bacillus cereus) and antioxidant (DPPH). The separation of the chemical components from both species was carried out using different chromatographic techniques (column chromatography and thin layer chromatography). The structures of isolated compounds have been elucidated through spectral analysis including 1D-NMR (1H, 13C and DEPT), 2D-NMR (1H-1H COSY, HSQC/HMQC and HMBC), IR, UV, MS (GCMS) and also by comparison with previous literature data. Studies on the chemical constituents of the bark of Alstonia spathulata has led to the isolation of five triterpenes; β-amyrin 113, β-amyrin acetate 114, β-sitosterol 115, lupeol acetate 116, stigmasterol 117 and a mixture of three triterpenes (lupeol 118, α-amyrin 119 and β-amyrin 113). Four known tritepenes were also successfully isolated from the root of Kopsia singapurensis; β-amyrin 113, β- amyrin acetate 114, lupeol acetate 116 and stigmasterol 117. These compounds were isolated for the first time from both species. Compound 113, 114, 116 and 117 exhibited cytotoxic effects against MCF-7 cell line with IC50 values of 15.5, 22.5, 26.0 and 14.5 μg/mL, respectively. All triterpenes showed weak antioxidant activity with IC50 > 500 μg/mL and were not active against the gram positive bacteria, Bacillus cereus. Both species have been traditionally used to cure diseases however there are not many publications on triterpenes extracted from this plants species. Isolation of chemical constituents from these two species has potential for producing new drugs