Inhibition of protein glycation, antioxidant and antiproliferative activities of Carpobrotus edulis extracts

Carpobrotus edulis is an important South African medicinal plants used as a food and therapeutic agent in traditional medicine. The aim of this study was to determine the phytochemical content, antioxidant, antiglycation and cytotoxic effect against Human Colon Cancer Cell Line (HCT-116) of aqueous and ethanol-water (1: 1 v/v) extracts of Carpobrotus edulis. The content of total phenolics and flavonoids in aqueous and ethanol-water extract were 151.99 mu g and 66.35 mu g gallic acid equivalents/mg of dry extract, and 38.84 mu g and 21.96 mu g quercetin/mg of dry extract, respectively. Furthermore, phenolic compositions analysis indicated the presence of seven majority compounds including sinapic acid, ferulic acid, luteolin7-o-glucoside, hyperoside, isoquercitrin, ellagic acid and isorhamnetin 3-O-rutinoside. The ethanol-water extract (100-1000 mu g/mL) showed better antioxidant activity than aqueous extract. Furthermore, Carpobrotus edulis extracts, especially ethanol-water extract significantly inhibited the formation of fluorescent advanced glycation end products, prevented oxidation-induced protein damage and exhibited a cytotoxic effect against HCT116 cells, with a significant decrease in cell viability after 24 h of incubation. The results obtained suggest that the Carpobrotus edulis extracts could be used as an easily accessible source of natural antioxidants and as potential phytochemicals against protein glycation and colon cancer. (C) 2016 Elsevier Masson SAS. All rights reserved.