The highest cytotoxicity was observed for the polyphenolic rich fractions. The methanolic extract and polyphenolic rich fraction of B. africana were more cytotoxic than the aqueous extract, whereas the methanolic extract of S. cordatum was less toxic than its aqueous extract. The C2C12 cell line was more suscep tible to the cytotoxicity induced by B. africana extracts selleck inhibitor than the 3T3 L1 cell line, while the inverse was observed with S. cordatum extracts. In the present study, the cytotoxicity of the aqueous extract of B. africana in 3T3 L1 cells was comparable to that described for an ethanolic stem ex tract using the brine shrimp toxicity assay. The cytotoxicity noted for the crude extracts and polyphenolic rich fraction of S.
cordatum is comparable to that obtained for dichloromethane methanol and ace tone extracts using human Inhibitors,Modulators,Libraries kidney Inhibitors,Modulators,Libraries epithelial cells and green monkey Vero cells, although the latter cells showed no toxicity to methanolic extracts. Although the mechanism of action of cytotoxicity of the crude extracts and polyphenolic rich fractions ob served in the present study and in those reported in the literature is not known, indications are that poly phenols may produce cell death in the 3T3 L1 cells due to their inherent anti adipogenic activity, by inducing cell cycle disturbances and initiation of apoptosis. Attenuation of oxidative stress induced parameters in U937 cells Protection against AAPH induced ROS generation, lipid peroxidation, apoptosis and cytotoxicity AAPH generated approximately 17 fold higher levels of ROS than the negative control over a 3 h period.
Pre treatment with crude extracts and polyphenolic rich fractions for 1 h reduced this ROS generation. Inhibitors,Modulators,Libraries While crude extracts of B. africana had superior activity compared to that Inhibitors,Modulators,Libraries of S. cordatum, the polyphenolic rich fraction of S. cordatum surpassed that of B. africana, resulting in 80% inhibition at 2. 5 ug ml. Cell viability was reduced to 73. 68% after exposure to AAPH, but pre treatment with crude extracts and polyphenolic rich fractions of both plants increased survival of cells to above 80%. The polyphenolic rich fraction of S. cordatum tended to protect the cells to a greater degree than B. africana but the difference in this protection was not significant. Lipid peroxidation was induced after exposure to AAPH as measured by MDA formation.
Re duction of MDA concentrations was observed for both crude extracts and polyphenolic rich fractions of B. africana. However, only the polyphenolic rich frac tion of S. cordatum had a protective effect. AAPH exposure increased apoptosis as measured Inhibitors,Modulators,Libraries by caspase 3 activity by 33. 6%. While all experienced samples of B. africana were able to decrease caspase 3 activity, only the polyphenolic rich fraction of S. cordatum elicited a definitive response.