Diet supplemented with phytochemical epigallocatechin gallate and probiotic Lactobacillus fermentum confers second generation synbiotic effects by modulating cellular immune responses and antioxidant capacity in aging mice

Purpose In the present study, we systematically identified and evaluated a synbiotic combination of phytochemical epigallocatechin gallate (EGCG) and probiotic bacteria in amelioration of immunosenescence and oxidative stress in aged mice. Methods Inhibitory effects of EGCG against different bacterial species were evaluated in vitro, followed by analysis to identify potential combination of EGCG and probiotic bacteria against alleviation of oxidative and inflammatory stress ex vivo. The best synbiotic combination, vis-à-vis prebiotic and probiotic supplementation alone, was then evaluated in aged Swiss albino mice for modulation of various immunological and antioxidative parameters. Results EGCG strongly inhibited the growth of pathogenic microbes as compared to probiotic bacteria. A combination of EGCG with probiotic Lactobacillus fermentum (LF) provided evidence of additive effects in the amelioration of oxidative and inflammatory stress-induced cell death. In vivo study revealed that combined supplementation of LF and EGCG significantly enhanced neutrophil oxidative index, CD3+ cell numbers and activation status, Th1/Th2 cytokines in splenic supernatants as well as liver Nrf-2 expression in comparison with treatments with LF or EGCG alone. The combined application of EGCG and LF did not simply result in additive or synergistic effects in relation with individual treatments. Conclusion These observations suggest that EGCG could be considered as a potential prebiotic that can offer second generation synbiotic health beneficial effects for the alleviation of some of the deleterious aspects of immunosenescence and aging.