Induction of apoptosis and cell cycle arrest by Negombata magnifica sponge in hepatocellular carcinoma

Marine sponges have been considered as a gold mine, with respect to the diversity of their secondary metabolites. Many sponge extracts and isolated compounds are potential anticancer agents. In the present study, the antiproliferative activity of Negombata magnifica was investigated as petroleum ether extract (PE), total methanolic extract (ME) and two sub-fractions II and III, isolated pure compounds (palmitic acid and pregnanediol), sponge mesohyl and primmorphs ethyl acetate extract. Palmitic acid was used as a positive control. Cell viability was assessed via MTT assay, and apoptosis was investigated in terms of DNA fragmentation and BCl2 gene expression. Cell cycle analysis was performed via flow cytometry. GLC analysis of PE revealed that it contains 84.46 % hydrocarbons and 15.54 % sterols, whereas the fatty acids contain 38.62 % saturated and 61.38 % unsaturated fatty acids. Results revealed that except for pregnanediol and fraction II, all treatments exhibited cytotoxic activity. Primmorphs ethyl acetate extract and fraction III arrested cells in G0–G1, while fraction II arrested cell cycle in G2/M. PE extract arrested cells in G0–G1 and G2/M. Mesohyl, PE and fraction III could be apoptotic agents as indicated by DNA fragmentation independent on BCL2 expression, while ME and pregnanediol could exhibited pro-apoptotic effect through decreasing BCL2 expression although no DNA ladder was observed.