Calystegia soldanella Extract Exerts Anti-Oxidative and Anti-Inflammatory Effects via the Regulation of the NF-κB/Nrf-2 Pathways in Mouse Macrophages

Plant polyphenols are widely used to treat various inflammatory diseases, owing to their ability to suppress reactive oxygen species production and the expression of inflammatory cytokines. Herein, we investigated phenolic compounds from Calystegia soldanella using UPLC Q-TOF MS/MS and their antioxidative and anti-inflammatory activities were analyzed. The C. soldanella ethyl acetate fraction (CsEF) had the strongest antioxidative activity, given its high polyphenol compound content. It also exhibited anti-inflammatory effects, inhibiting the production of inflammatory cytokines such as NO, PGE2, IL-1β, IL-6, and TNF-α in LPS-stimulated mouse macrophages. CsEF activated the nuclear transcription factor Nrf-2, thereby upregulating antioxidant enzymes such as HO-1 and NQO-1 and inhibiting NF-κB expression, which in turn, suppressed the expression of COX-2, iNOS, and inflammatory cytokines, ultimately exerting anti-inflammatory effects. Further, UPLC-Q-TOF-MS/MS was used to analyze the polyphenol compound contents in CsEF. The quercetin glycosides isoquercitrin and quercitrin were the primary flavonoid compounds, while the caffeic acid derivatives, chlorogenic acid and dicaffeoylquinic acid, were the primary phenolic acids. Thus, C. soldanella, which had only a limited use thus far as a medicinal plant, may serve as a natural medicinal resource for treating inflammatory diseases.