Abstract
BackgroundApocynum venetum leaves are used as a kind of phytomedicine and the main ingredient in some traditional Chinese medicine products for the relief of colitis. To understand the bioactive constituents of A. venetum L., we did a phytochemistry study and investigated anti-Inflammatory effects of compounds and explored the underlying mechanisms.MethodsWe isolated compounds from ethanol extract of A. venetum L. leaf and detected the most effective compound by NO inhibition assay. We investigated anti-Inflammatory effects on dextran sulfate sodium (DSS)-induced colitis mice and lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The disease activity index was determined by scores of body weight loss, diarrhea and rectal bleeding; histological damage was analyzed by H&E staining; macrophages change in the colon were analyzed by immunohistochemistry (IHC); myeloperoxidase activity was measured by myeloperoxidase assay kits; levels of proinflammatory cytokines were determined by qPCR and ELISA; protein production such as COX-2, iNOS, STAT3 and ERK1/2 were determined by western blotting.ResultsWe isolated uvaol from ethanol extract of A. venetum L. leaf and found uvaol has excellent potential of inhibiting NO production. We further found uvaol could attenuate disease activity index (DAI), colon shortening, colon injury, and colonic myeloperoxidase activity in DSS-induced colitis mice. Moreover, uvaol significantly reduces mRNA expression and production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β, and MCP-1) and infiltration of macrophages in colonic tissues of colitis mice. Studies on LPS challenged murine macrophage RAW246.7 cells also revealed that uvaol reduces mRNA expression and production of pro-inflammatory cytokines and mediators. Mechanically, uvaol inhibits the pro-inflammatory ERK/STAT3 axis in both inflamed colonic tissues and macrophages.ConclusionsA. venetum leaf contains uvaol and uvaol has potent anti-inflammatory effects on DSS-induced experimental colitis and LPS-stimulated RAW264.7 macrophage cells. These results suggest uvaol is a prospective anti-inflammatory agent for colonic inflammation.
Highlights
Apocynum venetum leaves are used as a kind of phytomedicine and the main ingredient in some tradi‐ tional Chinese medicine products for the relief of colitis
dextran sulfate sodium (DSS) treatment curtail the colon length of mice and this shortening was greatly improved after administration with uvaol and CsA, and ANOVA showed significant overall differences between all groups (F = 7.287, Fig. 2 Effects of uvaol on body weight gain (a), disease activity index (DAI) (b), colon length (c), myeloperoxidase (MPO) activity (d) and histological damage (e) of DSS-treated mice
In the current study, we observed that administration of uvaol attenuate the severity of DSS-induced colitis in mice, as affirmed by reduced clinical manifestations, colon shortening, histological damage and colonic myeloperoxidase activity, which is associated with suppression of colonic macrophage activation via inhibition of Extra‐ cellular regulated protein kinases (ERK)/Signal transducer and activator of transcription 3 (STAT3) signaling pathway
Summary
Apocynum venetum leaves are used as a kind of phytomedicine and the main ingredient in some tradi‐ tional Chinese medicine products for the relief of colitis. To understand the bioactive constituents of A. venetum L., we did a phytochemistry study and investigated anti-Inflammatory effects of compounds and explored the underlying mechanisms. Du et al Chin Med (2020) 15:43 in developing nations due to the western diet and lifestyle, bringing a substantial burden to patients, health care system and society worldwide [2, 3]. The current treatment for IBD includes 5-aminosalicylic acid (5-ASA), corticosteroids, immunosuppressant agents, biological therapies and antibiotic therapies. These existing therapeutic options are effective in treating IBD clinically, they have consequential limitations such as side effects, tolerance of patients, and high medical cost of drugs [4]. It is paramount to explore innovative therapies and potential medications for IBD
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