Growth inhibition of human liver carcinoma HepG2 cells and α-glucosidase inhibitory activity of Murdannia bracteata (C.B. Clarke) Kuntze ex J.K. Morton extracts

The juice of the entire fresh herb and infusion of dried sample of Murdannia bracteata are consumed to treat liver cancer and diabetes in Malaysia. However, no scientific evidence of these bioactivities has been reported. To verify the therapeutic potentials of sequential extracts and infusion of this plant by determining its cytotoxicity against human liver carcinoma HepG2 cells and α-glucosidase inhibitory activity. The cytotoxic activities of the extracts against HepG2 were determined using a methylene blue assay, and an α-glucosidase inhibitory assay was used to assess anti-diabetic activity. The molecular basis of the anti-hepatocellular carcinoma activity of the most active extract was determined using RT-PCR. Chemical profiling of the most active extract was performed using GC–MS and UPLC analyses. The results obtained from the cytotoxic screening revealed the dose-dependent growth inhibition of the HepG2 cells by only the hexane extract, with an EC50 value of 37.17±1.00µg/ml. The HepG2 cell death was found to be apoptotic in nature and based on the significant biphasic induction of caspase-3, suggesting that the extract inhibited cell growth through a caspase-3-dependent pathway. The hexane extract also displayed α-glucosidase inhibitory activity, with an EC50 of 117.04±2.34µg/ml. GC–MS analysis revealed that α-tocopherol was the major volatile compound in the hexane extract, and two phenolics (apigenin and caffeic acid derivatives) were detected using UPLC. Based on various published reports, it could be suggested that α-tocopherol and apigenin derivatives might be involved in the apoptosis-based cytotoxicity of the active extract of this plant against HepG2 carcinoma cells. The effects of this plant in the treatment of diabetes can be related to the presence of α-glucosidase inhibitors, such as the caffeic acid derivative identified in the active extract. [Display omitted]