Assessment of Anti-Proliferative Activities of Selected Medicinal Plant Extracts Used for Management of Diseases around Lake Victoria Basin

The devastating effect of cancer is a worldwide concern. Unfortunately current chemotherapeutic and radio therapeutic modalities have been found to possess side effects coupled with the emergence of drug resistance. This has necessitated the search for novel therapeutic products with better efficacy, safety and affordability through identification of anti-tumor agents from natural products. In this study the antineoplastic activity and phytochemical screening of methanol extracts of four medicinal plants that are native to Lake Victoria Basin, including Piptadiniastrum africanum, Kigelia africana, Centella asciatica and Chaemocrista nigricans was investigated. Extraction and concentration of the collected and dried plant samples to obtain crude extracts as well as phytochemical screening of the crude extracts was done following standard procedures. Lung adenocarcinoma cell line, from American type cell culture (ATCC), was exposed to the extracts and antiproliferative analysis using 3-(4, 5-Dimethyl-2-thiazolyl)-2, 5-diphenyl-2-tetrazolium bromide (MTT) colorimetric assay was performed. Phytochemical analysis of each of the four plants showed presence of terpenoids, alkaloids, saponins, tannins and steroids. Steroids were higher in the bark of P. africanum and the fruits of K. africana. Flavonoid was absent only in extracts of C. nigricans and coumarins present only in the extracts of K. africana. The methanolic extracts of the fruits of K. africana, bark of P. africanum, leaves of C. asciatica and leaves C. nigricans had inhibitory effects with IC50 28.86 ug/ml, 26.57 ug/ml, 15.69 ug/ml and 8.07 ug/ml (p values of 0.079, 0.069, and 0.042 and 0.055, ANOVA) respectively. Statistical differences among fractions of the extract were determined by one way ANOVA and considered significant at P<0.05. The MTT assay results indicated that all of the extracts had the capacity to inhibit the proliferation of tumor cells. The Phytochemical compounds which were tested are antioxidant and shown to trigger morphological changes, such as blebbing pattern and cell shrinkage, associated with apoptosis in the lung adenocarcinoma cell lines. The varying inhibitory activities against tested human lung adenocarcinoma cell lines justify the traditional use of these plants in the management of cancers and other illnesses. These extracts have a potential to be further developed into anti-tumor agents. However, further phytochemical characterization of the extracts is necessary for more extensive biological evaluation of the active ingredients and to exhaustively describe the mechanisms of cancer cell apoptosis of these four plant extracts.