Cytotoxicity Analysis of Nineteen Medicinal Plants Extracts on Breast Adenocarcinoma (MCF-7) and Rhabdomyosarcoma (RD) Cancer Cell Lines

The burden of cancer is alarmingly great on humans. However, the relevance of plants in combating cancer cannot be undermined. We joined the global search for anticancer agents from plants by screening nineteen (19) medicinal plant extracts on human breast carcinoma (MCF-7) and rhabdomyosarcoma (RD) cell lines using the 3- [4, 5-dimethylthiazol–2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Vincristine was used as the positive reference. Results were presented as mean IC50±standard error of the mean using GraphPad Prism (6.0). One-way ANOVA was used to establish the level of statistical significance. The results showed that twelve of the extracts were moderately cytotoxic on MCF-7 while seven were moderately active on RD (IC50, 30-100 μg/mL). Two of the extracts, Afzelia africana stem and Anogeissus leiocarpus root, showed significant activity on MCF-7 while seven had significant activity on RD (IC50 30 μg/mL) (P 0.05). Calliandra portoricensis root had the highest activity on RD (2.57±0.88 μg/mL). Anogeissus leiocarpus root and Olax subscorpioidea root showed significant activity on both cancer cell lines (RD: 13.82±2.05; MCF-7: 25.64±7.58 μg/mL and RD: 6.89±2.10; MCF-7: 36.47±1.57 μg/mL, respectively). Most of the extracts also demonstrated selectivity for the cancer cell lines. Bio-guided fractionation of four active extracts revealed that activity lies in the hexane and dichloromethane regions, inhibiting between 60-82% proliferation of the cell lines, at 50 μg/mL. This study demonstrated that the selected plants possess cytotoxic properties. Further investigations are underway to isolate and characterize the active fractions’ cytotoxic molecules.