Cytotoxic and Apoptotic Effects of Sprouted and Non-sprouted Lentil, Green and Yellow Split-peas

Abstract

Legumes such as lentils, green and yellow split-peas have been reported to provide health benefits against colon cancer due to nutrients and non-nutrient phytochemical compounds present in them. The aim of this study was to investigate the effect of selected legumes in inducing cytotoxicity, apoptosis and/or necrosis in human epithelial colorectal adenocarcinoma cells. Methanolic extracts of sprouted and non-sprouted legumes (Lentils, green peas, yellow peas) were prepared. Caco-2, human colonic carcinoma cell line was obtained from the American Type Culture Collection (ATCC, Manassas, VA). Cells were incubated with legume extracts at selected concentrations (1.5, 3, 4.5, 6, 7.5 and 10 mg mLG 1 ) for determination of lactate dehydrogenase (LDH) release (cytotoxicity %). The ability of legume extracts in inducing cell apoptosis was analyzed at selected concentrations of 1.5, 3, 6 and 12 mg mLG 1 by quantifying DNA fragmentation. Morphological changes in cells were observed microscopically. The activity of caspase-3 enzyme was also determined. Results showed that legume extracts induced cytotoxicity in caco-2 cells in a dose-dependent manner. A 20-80% increase in release of LDH was observed in cells incubated with extracts compared to untreated cells. Total fragmented DNA (%) was higher in cells treated with sprouted legume extracts compared to their non-sprouted extracts. More than 40% of total DNA fragmentation was observed in cells treated with sprouted legumes. Caspase-3 activity was highest in cells incubated with non-sprouted yellow split peas at 6 mg mLG 1 . Specific morphological changes related to apoptosis such as: surface blebbing, formation of apoptotic bodies, blisters and echinoid spikes and cell membrane destabilization were observed in cells incubated with extracts. These results suggested the cytotoxic and apoptosis inducing potential of legume extracts. Bioactive components in these selected legumes may be used as chemopreventive agents.