Abstract
Cancer is a devastating and aggressive disease that is globally ranked as the second-leading cause of deaths despite the relentless efforts being directed towards the discovery of novel chemotherapeutic drugs. Plants naturally produce a plethora of secondary metabolites that play a crucial role as effective therapeutic agents. Cancer treatment rely primarily on chemo- and radio-therapeutic strategies that suffers from known side effects. Recently, the strategy of controlling cancer progression by use of plant-derived natural products have extensively attracted research interests. In this study, the antioxidant and anticancer activities of the methanolic extract of Calligonum comosum (MeCc) fruit hairs were investigated. According to DPPH and ABTS assays, MeCc exhibited potent antioxidant capacity as it displayed significant free-radical scavenging activity. Results of the MTT cytotoxicity assay revealed that the MeCc exhibited potent anti-proliferation activity (IC50 = 10.4 µg/ml) that is specific against human hepatocarcinoma cells (HepG2), as only marginally harmful effect against non-cancerous control BJ-1 cells was detected. Results of the RT-qPCR gene expression analyses indicated that MeCc resulted in significant overexpression of mRNA transcript levels of the pro-apoptotic genes p53, caspase-3 and Bax, while downregulating the level of Bcl-2, an anti-apoptotic marker gene. Immunoblotting of the protein expression levels for the same markers showed similar pattern to that observed in RT-qPCR profiling. While the levels of p53, caspase-3 and Bax proteins exhibited significant increase, the protein level of Bcl-2 was significantly reduced. In conclusion, it is proposed that the observed specific anticancer activity of MeCc against HepG2 cells takes place via the engagement of apoptosis. This highlights the value of C. comosum as a source of potent natural anticancer agents and warrants further investigation to identify the active principals involved.