In Vitro Anti-Proliferative Activity of Selected Plant Extracts Against Cervical and Prostate Cancer Cell Lines

Abstract

Prostate and cervical cancers are among the leading cancer in men and women respectively. The World Health Organization ranks cervical cancer as the fourth most common cancer among women globally. The numbers are estimated to be 604,000 new cases and 342,000 deaths in 2020. From this, about 90% of the new cases and deaths worldwide in 2020 occurred in low and middle-income countries in the world (WHO, 2022). Current conventional cancer therapies like chemotherapy and radiotherapy present severe side effects and in many developing countries are inaccessible to many cancer patients. Traditional plant-based medicines have long been used to treat various diseases as the plants are readily available. However, the inadequate understanding of the therapeutic mechanisms at a cellular level has contributed to the growing difficulty of bringing these drugs to conventional use. Using the MTT assay method, this study investigated the anti-proliferative activity of methanol and water extracts from four plant species- namely Aloe secundiflora, Maytenus obscura, Vernonia zanzibarensis and Dichrostachys cinerea, against prostate cancer cells (Du145 and 22RV1), cervical cancer cells (HeLa) and African green monkey (Vero) cell lines. The extracts studied suppressed the growth of the cancer cells in a dose-dependent manner at concentrations of 1.37 µg/ml to 1000 µg/ml. Extracts of V. zanzibarensis reported low antiproliferative activity against DU145, 22RV1 and HeLa cell lines while the aqueous extract of M. obscura stem bark and A. Secundiflora had moderate activity on DU145, 22RV1 and HeLa. The methanol extract of D. cinerea stem bark had the highest anti-proliferative activity with an IC50 of 8.04 ± 2.8 µg/ml against the 22RV1 cells and a low cytotoxic effect against the Vero cells with CC50 of 812.1 ± 12.72µg/ml. This study shows that the D. cinerea stem bark has anti-proliferative activity with low cytotoxicity to normal cells. These results suggest that the D. cinerea stem bark extract anti-proliferative activity can be linked to its ability to up-regulate the expression of tumor suppressor gene p53. This was after analysis of p53 gene modulation by the D. cinerea stem bark extract which showed that the extract upregulated the gene expression in Du145 cells by 1.76 folds. The conclusion of this study details the survey literature of ethno medicinal uses and validates phytochemical profile for management of cancer after an investigative focus to the synergistic pharmacological effect in killing the cancer cells.