Oxidative damage to enteric system and its modulation by synbiotic action of Probiotics and Prebiotics

Abstract

This study was aimed to investigate the potential of some probiotics and prebiotics with respect to antioxidant, anti-inflammatory, antimicrobial, anticancer and radio-protective activities. Lactobacillus rhamnosus was used as a probiotic model system. The fruits of the three dietary cucurbits [Lagenaria siceraria (Ls), Luffa cylindrica (Lc) and Cucurbita pepo (Cp)] were used as prebiotics. Ls contained maximum quantity of flavonoids (17.9 ± 1.27 mg/g) as compared to Lc (6.25 ± 0.24 mg/g) and Cp (2.05 ± 0.53 mg/g). Ls rendered maximum antioxidant activity as compared to Lc and Cp. Maximum reduction potential was observed in case of Ls extract (about 44% at 500 µg). Ls and Cp enhanced the antimicrobial activity of L.rhamnosus. MTT assay demonstrated that against both HT-29 cells and HCT-15 cells, Lc was found to be most effective (IC50 being 147 ± 4.5 and 167 ± 3.0 and#956;g/ml). Caspase-3 assay revealed that treatment of Ls, Lc and Cp extract (at IC50) increased the frequency of apoptosis over the control value to about 30, 12 and 16 % respectively in HT-29 and 33, 20 and 10 % respectively in HCT-15 cells. Cp extract decreased the secretion of pro-inflammatory cytokine IL-8, from 61 to 44 %. Corresponding increase of Lc and Ls extract brought down the IL-8 secretion from 80 to 48 % and 81 to 53 % respectively. Flow-cytometric analysis of cell cycle showed that Ls, Lc and Cp extract increased the accumulation of cells in G2 phase to about 42, 34 and 37% respectively as compared to control (20%). The area of the villi was increased in the Ls + radiation treated group (34587 µm2 ) as compared to radiation-alone treated group (29768 µm2 ).The structural integrity of tight Junction was improved in presence of Ls which was disrupted by radiation. It is concluded that these dietary cucurbits have the potential to protect the gut from various diseases.