Cytotoxic and anti-proliferative effects of Moringa Oleifera Lam.on hela cells.

Abstract

Moringa oleifera Lam., known to most as the ‘drumstick tree’, is a non-fastidious botanical that is native to India, and is cultivated on a global scale as a sustainable crop, for sustenance, medicinal and beauty applications, amongst others. The antitumour, antibacterial and antifungal effects of M. oleifera are well-documented, however, its specific effects on human papillomavirus (HPV)-induced malignancy have not been established. High-risk HPV subtypes 16 and 18 are implicated in the carcinogenesis of more than 90% of cervical cancers. Despite well-established national cervical screening programmes, cervical cancer still remains the most common cancer affecting females in South Africa. This may partly be attributed to the high incidence of HIV infection in South Africa. Some of the hallmarks of cancer are, the up-regulation of telomerase, over-expression of E2F1 transcription factor, and over-expression of cyclin E and cyclin B1. The aim of this current study was to establish whether 24-hour treatment with hexane and ethanol leaf extracts of M. oleifera modulate telomerase, E2F1, cyclin E, and cyclin B1. The apoptotic pathway and phase of cell cycle arrest were also investigated. The HeLa cell line, an aggressive cervical cancer cell line in which high-risk HPV-18 viral strands have been identified, was used in this study A novel effect of M. oleifera leaf extract was evident in the inactivation of telomerase. The inactivation of telomerase implies that p53 function was restored by the repression of E6 gene expression. Another novel outcome of the study is that M. oleifera down-regulates E2F1, accounting for the dose-dependent antiproliferative effects seen. The inactivation of telomerase was demonstrated by caspase-3 and caspase-7 activation, which confirmed intrinsic apoptosis. The down-regulation of E2F1 possibly occurs through the repression of the E6 oncoprotein and the activation of p53. The quantitative assessment of cyclin E and cyclin B1, showed an overall down-regulation, and G2-M cell cycle arrest. Taken together, this study provides convincing evidence that M. oleifera hexane and ethanol leaf fractions have potential antitumour effects, by targeting multiple abnormally elevated markers for down-regulation. Other M. oleifera fractions investigated in a parallel study, and were excluded due to p values being greater than 0.05 and inconclusive findings, in dichloromethane and aqueous fractions.