A new natural product from the leaves of Olinia usambarensis and evaluation of its constituents for cytotoxicity against human ovarian cancer cells

Natural products play a significant role in cancer therapy and prevention; with considerable number of anticancer in use are either natural products or their derivatives. In this study, chromatographic separation of CH2Cl2/CH3OH (1:1, v/v) extract of the leaves of Olinia usambarensis gave four compounds among which compound 1, caffeoyloxy-5,6-dihydro-4-methyl-(2H)-pyran-2-one is a new natural product. The structures of the identified compounds were established using spectroscopic and mass spectrometric analyses. The crude extract and isolated compounds were evaluated against the human ovarian cancer cell lines, A2780 and SKOV3, and showed IC50 of 79-170 and 74-136 μM, respectively. The crude extract and isolated compounds were also tested against normal cell, an immortalized ovarian surface epithelial (IOSE) cells, but did not show activity up to 100 μM.