Bioactive components from the tea polyphenols influence on endogenous antioxidant defense system and modulate...

The present study aimed to evaluate the radioprotective efficacy of green tea polyphenols and the component ingredients against irradiated-induced damage in mice and elucidate the underlying mechanisms. Green tea polyphenols (GTP 50, 50 and 100 mg/kg, p.o. daily) and its four individual components (25 and 50 mg/kg, p.o. daily) were administrated to the irradiated-injured mice for 21 days. The radioprotective effect on the hematopoietic system, serum cytokines, and endogenous antioxidant enzymes was studied. GTP 50 significant revert the irradiated-induced decline in hematological parameters (RBCs, WBCs, Hb), meanwhile, protected antioxidant defense system, as evidenced by decreased of serum lipid peroxidation (malonyldialdehyde) and elevation the antioxidant enzyme superoxide dismutase (SOD). Among the GTP components, catechin showed the best effect on elevation of hematological parameters, and epigallocatechin gallate showed the best antioxidant activity. Moreover GTP and its bioactive components (catechin, epigallocatechin and epigallocatechin-3-gallate) assisted in decreasing the leukocytopenia seen after whole mice irradiation and significantly reduced the elevated serum inflammatory cytokines (TNF-α, IL-1β, and IL-6). Green tea polyphenols have a potential to be developed as radioprotective agents against irradiated-induced toxicity. Furthermore the antioxidant and anti-inflammatory activities of GTP can be attributed to the interaction of the different components through multiple and synergistic mechanisms.