ABSTRACT
Introduction: Cancer chemopreventive agents from natural sources have been actively investigated over the years to seek prevention against cancer. In this study, cocoa polyphenols extract (CPE) was examined to explore its antioxidant and cytotoxicity activities. Methods: CPE was analysed for total phenolic content (TPC) and antioxidant activity (DPPH radical scavenging activity and FRAP ferric-reducing antioxidant power assays). In vitro cytotoxicity effect of CPE against HepG2, HT-29, HeLa, MCF-7, MDA-MB-231 and WRL-68 cell lines after 48 h exposure was measured by MTT assay. Results: The study showed that CPE had higher total phenolic content (13560.0±420.1 mg GAE/100g dry weight of sample) than vitamin E (p<0.05). CPE exhibited strong antioxidant activity comparable with ascorbic acid in both DPPH (IC50 = 14.73±1.47 g/ml) and FRAP (2130.33±2.33 μM of FE/1 mg of dry weight of sample). The cytotoxicity study showed that CPE exhibited the highest cytotoxicity effect against MCF-7 with lowest IC50 value (3.00±0.29 mg/ml) compared to other cancer cell lines after 48 h treatment (p<0.05). Conclusion: Our results indicate that CPE demonstrated high total phenolic content, free radical scavenging activity, ferric reducing ability and cytotoxicity activity towards HepG2, HT-29, HeLa, A549, MDA-MB- 231 and MCF-7 cancer cell lines. Further isolation of bioactive constituents from CPE should be done to characterise its potential chemopreventive activity as well as to elucidate the mechanism of cancer cell death induced by CPE.
ABSTRACT
Introduction: Phytic acid (PA) has been shown to have positive nutritional benefits. There are also claims that it is able to prevent cancer through its antioxidant capability. This study investigated antioxidant activity and cytotoxic effect of PA extracted from rice bran against selected cancer cell lines (i.e. ovarian, breast and liver cancer). Methods: Cytotoxicity activity of PA was investigated using MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4- sulfophenyl)]-2H-tetrazolium, inner salt] assay while the antioxidant activity of PA extract, commercial PA and butylated hydroxytoluene (BHT) was determined by using five different assays: ferric thiocyanate (FTC) and thiobarbituric acid (TBA) assay, β-carotene bleaching method, DPPH radical scavenging assay and ferric reducing antioxidant power (FRAP) assay. Results: PA extracted from rice bran induced marked growth inhibition in ovary, breast and liver cancer cells with 50% growth inhibition concentration (IC50) values of 3.45, 3.78 and 1.66 mM, respectively but exhibited no sensitivity towards a normal cell line (3T3). The PA extract was also found to exert antioxidant activity when tested using the FTC, TBA, FRAP and β-carotene bleaching methods but antioxidant activity could not be attributed to scavenging free radical species as measured by DPPH radical scavenging assay. Conclusion: The PA extract from rice bran displayed safe and promising anticancer properties in selected cancer cell lines and it is believed that its antioxidant capability is the likely contributor to the observed anticancer properties.