Protective effect of active components of Eucommia ulmoides leaves on gastric ulcers in rats: Involvement of the PI3K/Akt/NF‐κB pathway

Eucommia ulmoides leaves are widely developed as food and medicines in China and Japan. Its main components have anti-inflammatory properties against gastric ulcers. The purpose of this study was to assess the protective role of an extract derived from the active components of Eucommia ulmoides leaves (EUL 50) against a gastric ulcer and analyze the underlying antiulcer mechanism. The main components of EUL 50 were identified using an ultra-performance liquid chromatography (UPLC) method. Network pharmacology and molecular docking were performed to predict the possible mechanism of action of EUL 50 in the treatment of gastric ulcers. The rats received EUL 50 intragastric administration twice a day for 3 days. Hydrochloric acid/ethanol (HCl/EtOH) was utilized to induce gastric ulcers, followed by histopathological and histochemical evaluation of the ulcer tissues and determination of the main oxidative stress parameters and inflammatory cytokines. The expression of PI3K/Akt/NF-κB pathway-related proteins was measured. Neochlorogenic acid, chlorogenic acid, rutin, and so on were identified as the major components of EUL 50 by UPLC. The prediction results identified the PI3K/Akt/NF-κB signaling pathway as the main possible protective mechanism against gastric ulcers. Furthermore, in a dose-dependent manner, EUL 50 reduced gastric tissue damage. In addition, the high dose of EUL 50 administration resulted in remarkable reductions in the levels of malondialdehyde (MDA), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin-1β (IL-1β) by 22.64%, 42.61%, 57.78%, and 56.51%, respectively, and suppression of the phosphorylation of Akt, p65, IKKα, and IκBα by 60.87%, 67.65, 74.58%, and 59.57%, respectively, and increased the antioxidant enzyme activity. EUL 50 is rich in flavonoids and organic acids that can act on the PI3K/Akt/NF-κB signaling pathway; as a result, oxidative stress and inflammation are considerably reduced, and gastric ulcers caused by HCl/EtOH are reduced. PRACTICAL APPLICATION: As a medicinal and food substance, Eucommia ulmoides leaves are widely used in the development of health products. EUL 50, a moderately polar part of E. ulmoides leaves, was obtained by extraction and enrichment and was found to have a better protective effect against HCl/EtOH-induced gastric ulcers. This finding can enrich the traditional application of E. ulmoides leaves and provide a basis for their health product development.