Aloe vera Inhibits Proliferation of Human Breast and Cervical Cancer Cells and Acts Synergistically with Cisplatin

Many of the anti-cancer agents currently used have an origin in natural sources including plants. Aloe vera isone such plant being studied extensively for its diverse health benefits, including cancer prevention. In this study,the cytotoxic potential of Aloe vera crude extract (ACE) alone or in combination with cisplatin in human breast(MCF-7) and cervical (HeLa) cancer cells was studied by cell viability assay, nuclear morphological examinationand cell cycle analysis. Effects were correlated with modulation of expression of genes involved in cell cycleregulation, apoptosis and drug metabolism by RT-PCR. Exposure of cells to ACE resulted in considerable lossof cell viability in a dose- and time-dependent fashion, which was found to be mediated by through the apoptoticpathway as evidenced by changes in the nuclear morphology and the distribution of cells in the different phasesof the cell cycle. Interestingly, ACE did not have any significant cytotoxicity towards normal cells, thus placingit in the category of safe chemopreventive agent. Further, the effects were correlated with the downregulation ofcyclin D1, CYP 1A1, CYP 1A2 and increased expression of bax and p21 in MCF-7 and HeLa cells. In addition,low dose combination of ACE and cisplatin showed a combination index less than 1, indicating synergisticgrowth inhibition compared to the agents applied individually. In conclusion, these results signify that Aloe veramay be an effective anti-neoplastic agent to inhibit cancer cell growth and increase the therapeutic efficacy ofconventional drugs like cispolatin. Thus promoting the development of plant-derived therapeutic agents appearswarranted for novel cancer treatment strategies.