Cytotoxic Activity of the Leaf and Stem Extracts of Hibiscus rosa sinensis (Malvaceae) against Leukaemic Cell Line (K-562)

Purpose: To evaluate the cytotoxic activity of Hibiscus rosa sinensis against K-562 cancer cell line. Methods: The crude petroleum ether, ethyl acetate and methanol extracts of the leaf and stem of Hibiscus rosa sinensis were prepared using cold extraction method. The in vitro cytotoxic activity of the extracts (20 - 100 μg/ml) was evaluated on leukaemic cancer cell line (K-562) and Mardin-Darby kidney cell line (MDBK) (control) using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays, followed by morphological detection with Hoeschst staining. Results: The methanol leaf extracts showed higher activity (IC50 value: 30.9 ± 1.1 μg/ml) against K-562 cells than petroleum ether and ethyl acetate extracts which exhibited IC50 of 87.6 ± 0.91 and 57.6 ± 0.61 μg/ml (p 0.05), respectively. Meanwhile, stem extracts from methanol showed IC50 of 79.80 μg/ml against K-562. MDBK cells (positive control) showed IC50 100 μg/ml for all the extracts. On treating K-562 cells with methanol leaf extract (30 μg/ml), the former were observed to undergo apoptosis with nuclear segmentation after 24 h incubation. The methanol leaf extract produced cell death on K-562 cells by apoptosis. Conclusion: Hibiscus rosa sinensis extracts possess potentials as effective cytotoxic agents against - 562 cells.