Phytochemical Screening and Synergistic Anti-proliferative Activity against Selected Cancer Cell Lines of Moringa oleifera and Indigofera arrecta Leaf Extracts

Medicinal plants present a plausible source for anticancer agents. Combination of plant extracts and plant-derived compounds with the currently used cancer drugs has shown a marked improvement of the conventional drugs' efficacy and reduced toxicity. This study evaluated; phytochemical screening, antiproliferative activity and drug interaction potentials of Moringa oleifera and Indigofera arrecta leaf extracts with 5-fluoro uracil against selected cancer cell lines. Phytochemical screening was done using standard procedures. The common 3– (4, 5-dimethylthiazol-2-yr) -2, 5-diphenyltetrazolium (MTT) assay was used to determine the growth inhibitory potential of the extracts towards cancer cells. Drug interaction assays were done using constant ratio combination method. Alkaloids, terpenoids, tannins, flavonoids, glycosides, phenols and saponins were found to be present in the plant's extracts. M. oleifera and I. arrecta methanol-dichloromethane extracts had the highest activity compared to water extracts. All the extracts showed antiproliferative activities towards; HCC 1395 (breast), DU145 (prostate) and Hela (cervical) cancer cell lines. The extracts were not cytotoxic towards Vero cells (IC50>1000 µg/ml). I. arrecta and M. oleifera inhibited DU145 the most with IC50 values of 111.110 µg/ml and 66.290 µg/ml respectively. The plant extracts synergistically inhibited the growth of cancer cells (CI<1). Combination of the plant extracts and 5-Fluorouracil depicted that the concentration of the conventional drug could be reduced and yet achieve the same desired effect against cancerous cells (Dose reduction index (DRI) >1). Further studies to isolate the bioactive compounds and deduce the probable mechanisms of action are recommended.