RESUMO
The aim of this study was to study the preventive effects of polyphenols extracted from Liubao Insect tea on gastric injury. The content of Liubao Insect tea polyphenols (LITP) was 72.36% by ion precipitation extraction method. HCl/ethanol-induced gastric injury in mice led to increased gastric juice volume and decreased pH. LITP increased the gastric juice pH value and reduced the gastric juice volume at slightly lower quantities than ranitidine. Visual observation of gastric tissue showed that LITP could effectively reduce the area of gastric injury, and higher concentrations of LITP had a greater effect. Pathological observation also confirmed that LITP can reduce the cell damage and inflammatory effects, and play a role in preventing gastric injury. Serum cytokine assays showed that LITP could reduce the levels of IL-6 (interleukin 6), TNF-α (tumor necrosis factor alpha) and IFN-γ (interferon gamma) induced by gastric injury, and the effects of higher concentration of LITP were similar to those of ranitidine. The results showed that LITP could increase SOD (superoxide dismutase) and GSH (glutathione) levels; decrease MDA (malondialdehyde) and MPO (myeloperoxidase) levels; up-regulate the expression of Cu/Zn-SOD (cuprozinc-superoxide dismutase), Mn-SOD (manganese superoxide dismutase), CAT (catalase), nNOS (neuronal nitric oxide synthase), eNOS (endothelial nitric oxide synthase); and down-regulate the expression of iNOS (inducible nitric oxide synthase), COX-2 (cyclooxygenase-2), TNF-α, and IL-1ß (interleukin-1 beta) in mice with gastric injury, thus inhibiting gastric injury. We demonstrate that LITP is an active substance which could prevent gastric injury in experimental animals. With the increase of LITP concentration, its effects on preventing gastric injury were stronger and similar to those of ranitidine.
