Hunan Insect Tea Polyphenols Provide Protection against Gastric Injury Induced by HCl/ethanol through an Antioxidant Mechanism in Mice

The purposes of this study were to explore the preventative and treatment effects of Hunan insect tea polyphenols (HITPs) on gastric injury in mice induced by HCl/ethanol and to investigate their molecular mechanisms of action. Both HITPs and ranitidine inhibited the formation and further deterioration of gastric mucosal lesions, reduced the secretion of gastric juices, and raised gastric juice pH compared to the control. The HITPs-H treated group had lower serum levels of motilin, substance P, and endothelin than the control group, but they had higher serum levels of vasoactive intestinal peptide and somatostatin. Mice treated with HITPs had lower serum levels of the cytokines interleukin (IL)-6, IL-12, tumor necrosis factor-α (TNF-α), and interferon-γ compared with those in the control group. The activities of superoxide dismutase (SOD), nitric oxide, and glutathione peroxidase (GSH-Px) were higher in the gastric tissues of HITP-treated mice, but malondialdehyde content was lower. Quantitative PCR analysis indicated that mRNA expression of occludin, epidermal growth factor (EGF), EGF receptor (EGFR), vascular EGF (VEGF), inhibitor kappaB-α, cuprozinc-superoxide dismutase, manganese-superoxide dismutase, GSH-Px, neuronal nitric oxide synthase, and endothelial NOS increased significantly in the gastric tissues of HITP-treated mice. However, activated B cells, inducible NOS, cyclooxygenase-2, TNF-α, IL-1 beta, and IL-6 mRNA expression levels were lower in the HITPs group than in the control group. The protective effect of a high concentration (200 mg kg−1 b.w.) of HITPs on gastric injury induced by HCl/ethanol was stronger than that of a low concentration (100 mg kg−1 b.w.). High-performance liquid chromatography (HPLC) revealed that the HITPs included cryptochlorogenic acid, (-)-epicatechin gallate, and isochlorogenic acid C. Taken together, our findings indicate that HITPs played a role in the prevention of gastric damage. The antioxidant effect of the HITPs contributed to their potential value in the prevention and treatment of gastric injury. HITPs have broad prospects as biologically active substances for food development.