Standardized aqueous extract of Abutilon theophrasti Medic. ameliorates oxidative stress and inflammatory responses against hydrochloric acid/ethanol-induced gastric ulcer in rats

Abstract

BackgroundThe herb Abutilon theophrasti Medic. (AT, Qingma in Chinese), a widely distributed medicinal plant in various regions worldwide, is commonly used in China for treating inflammatory diseases of the gastrointestinal (GI) tract, such as dysentery. However, the pharmacological basis of this herb for treating peptic ulcer, also an inflammatory condition in the GI tract, remains insufficiently understood.PurposeThe aim of this study is to investigate the ameliorating effects of a standardized aqueous extract of AT (ATAE) on experimental gastric ulcer (GU) in rats and explore whether the human GU-associated molecules/signaling pathways obtained using bioinformatics have a role to play in the drug’s efficacy for molecular mechanism elucidation.MethodsUltra-performance liquid chromatography (UPLC) and UPLC coupled to tandem mass spectrometry (UPLC-MS) were used for standardization of ATAE. GSE233973 and GSE264263 datasets with Helicobacter pylori (HP)-infected and normal human biospecimens from the Gene Expression Omnibus (GEO) database were normalized and subjected to identification of differentially expressed genes (DEGs). A protein–protein–substance network construction and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to explore and visualize the biological targets, effective substances, and signaling pathways involved in the anti-GU effects of ATAE. Hydrochloric acid/ethanol (HCl/EtOH)-induced GU rats and lipopolysaccharide (LPS)-stimulated RAW264.7 cells were used as models to investigate the GU-ameliorating effects and underlying mechanism of ATAE. Multiple bioassays/kits were employed to observe histopathological changes and expression/production levels of cytokines/molecules.ResultsA total of 26 compounds were identified in ATAE, comprising 10 flavonoids, 7 organic acids, 5 amines, and 4 other compounds. The content of rutin in ATAE was 0.38%. In vivo, ATAE markedly attenuated the HCl-/EtOH-induced GU and mucosal injuries; decreased the levels of pro-inflammatory/oxidant mediators, including TNF-α, IL-1β, IL-6, and malondialdehyde (MDA); increased the anti-oxidant activity of mediators superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px); and inhibited the phosphorylation/activation of Akt, IκBα, and NF-κB p65 in gastric tissues. In vitro, ATAE treatment significantly lowered nitric oxide (NO) and reactive oxygen species (ROS) production, attenuated nuclear translocation of NF-κB p65, and modulated mRNA expression levels of NF-κB-regulated mediators, including TNF-α, IL-1β, IL-6, MnSOD, GSH-Px, CAT, VCAM-1, and MMP-9. For the bioinformatics study, 24 hub genes were screened and found to be predominantly enriched in oxidative stress- and inflammatory response-associated pathways; quercetin and caffeic acid were identified as the most effective substances responsible for ATAE’s anti-GU effects. Overall, the presented results greatly supported and validated the essential inflammation and oxidation events implicated in the mechanistic investigation using bioinformatics.ConclusionATAE ameliorates oxidative stress and inflammatory responses against HCl/EtOH-induced GU in rats, which are probably associated with inhibiting the ROS/Akt/NF-κB signaling pathway. The novel findings of this study, for the first time, provide scientific justifications for the use of AT in treating peptic ulcer. Future studies are warranted to elucidate the clinical potential and a more comprehensive understanding of the underlying mechanisms of AT in treating GU.