Anti-rheumatoid arthritis effects of Caragana acanthophylla Kom. on collagen-induced arthritis and the anti-inflammatory activity of polyphenols as main active components.

Abstract

Ethnopharmacological relevance: Caragana acanthophylla Kom. is a folk medicine for treating rheumatoid arthritis (RA), widely used in Xinjiang of China. However, the pharmacological mechanism and possible material basis was not clear.

Aim of the study: This study was aimed to investigate the anti-rheumatoid arthritis effect of the 80% EtOH extract from Caragana acanthophylla Kom. aerial parts (ECA), as well as the potential pharmacological mechanism and possible material basis.

Materials and methods: RA model was induced by type Ⅱ collagen. Hind paw swelling, arthritis index score and pathological test were performed. The levels of MMP-2, MMP-3, MMP-9, as well as cytokines IL-1β, IL-6, IL-8, IL-10, IL-17A and TNF-α in serum were detected by ELISA. The expression of proteins IκB, p-IκB, COX-2 and iNOS were evaluated by western blotting. UHPLC-MS/MS was recorded the chemical composition. MS guided technology was subjected to isolate pure compounds from ECA. NMR and mass spectrometric were applied to identify the isolated compounds. In vitro anti-inflammatory of isolated compunds was measured by RAW 264.7 cells induced LPS. The cell viability was evaluated by MTT assay, and Griess reagent method was used to quantify the production of NO.

Results: ECA attenuated paws swelling, arthritis indexes and pathological changes of joints in RA rats, decreased the levels of MMP-3, MMP-9, as well as cytokines of IL-1β, IL-6, IL-8, IL-17A and TNF-α, besides increased the levels of cytokine IL-10 in serum. While the level of MMP-2 almost unchanged. In addition, the expression of p-IκB, COX-2 and iNOS were inhibited, while the expression level of IκB was promoted. Futhermore, phytochemical investigation revealed that 33 metabolites was detected from ECA. Then a new biflavonoid, caracanflavanone (1), a new lignan, caracanlignane (12), along with eleven known compounds were isolated. Compounds 1-8 and 11 inhibited LPS-induced NO production with the IC₅₀ values in the range of 23.91 to 64.14 μM.

Conclusion: ECA possessed strong anti-RA activity, which might be owing to the down-regulation of inflammatory cytokines IL-1β, IL-6, IL-8, IL-17A and TNF-α, and up-regulation of inflammatory cytokines IL-10, as well as inhibition of the protein expression of p-IκB, COX-2 and iNOS, and activation of the expression of IκB in NF-κB signaling pathway. Moreover, polyphenols might be provide a significant effect against RA.