Comparison of Antioxidant Effect between Insect Tea and Its Raw Tea

This chapter was designed to compare the antioxidative effects of Insect tea polyphenols (ITP) and its raw tea (Kuding tea) polyphenols (KTP) on D-galactose induced oxidation in Kunming (KM) mice. KM mice were treated with ITP (200 mg/kg) and KTP (200 mg/kg) by lavage, respectively; and vitamin C (VC, 200 mg/kg) was also treated as positive control by lavage. After determination in serum, liver and spleen, ITP treated mice showed the higher superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione (GSH) activities and lower nitric oxide (NO), malonaldehyde (MDA) activities than VC treated mice, KTP treated mice and untreated oxidation mice (control group). By H&E section observation, the mice induced by D-galactose induced oxidation showed more changes compared to normal mice and oxidative damage appeared in liver and spleen tissues; ITP, VC and KTP could improve the oxidative damage of liver and spleen tissues, meanwhile the effects of ITP were better than VC and KTP. Using quantitative polymerase chain reaction (qPCR) and western blot experiments it was observed that ITP could raise the mRNA and protein expression of neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), manganese superoxide dismutase (Mn-SOD), cupro/zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), heme oxygenase-1 (HO-1), nuclear factor erythroid 2 related factor 2 (Nrf2), gamma glutamylcysteine synthetase (y-GCS), NAD(P)H:quinone oxidoreductase 1 (NQO1) and reduce inducible nitric oxide synthase (iNOS) expression in liver and spleen tissues compared to control group, and these effects were stronger than VC and KTP. Both ITP and KTP had strong antioxidative effects, but ITP's effects were better than KTP's after insect transformation, much better than VC. As a result, ITP can be used in functional foods as an antioxidant and anti-aging agent.