Assessment of the Cytotoxicity, Cell Cycle Arrest and Pro-apoptotic Effects of Two African Botanicals, Lantana ukambensis (Vatke) Verdc and Balanites aegyptiaca (L.) Delile on Human Colorectal Cancer Cells

Lantana ukambensis (Vatke) Verdc. (Verbenaceae) and Balanites aegyptiaca (L.) Delile (Zygophyllaceae), are used in African traditional medicine for the treatment of wounds and inflammatory diseases. The purpose of this study is to assess the cytotoxicity, cell cycle arrest, and pro-apoptotic effects of the extracts and fractions of these plants against HCT-116 and HT-29 cells. MTS, crystal violet, Hoechst staining, annexin V/PI and cytometry methods were used in this study. The crude extracts of these plants showed significant cytotoxic effects against HCT-116 and HT-29 cells. The 1-butanol and ethyl acetate fractions of L. ukambensis decreased the G1 phase by 20.53% and 28.47% and increased the G2/M by 23.47% and 25.90%, respectively, on HCT-116. Moreover, the 1-butanol fraction increased the cumulative value of apoptotic cells by 49.77% on HCT-116 and the ethyl acetate fraction increased this value by 53.37% at 15 µg/mL after 48 hours of exposure. In the case of B. aegyptiaca, the ethyl acetate fraction increased G1 phase by 3.83% on HCT-116 and by 8.6% on HT-29, whilst G2/M phase was decreased by 5.63 % on HCT-116 and by 6.62% on HT-29. Moreover, apoptotic cells were increased by 11.4% on HCT-116. The outcome of this study suggests the potential of the ethyl acetate fraction of each plant for the isolation of natural anticancer molecules against colorectal cancer.