Styphnolobium japonicum (L.) Schott Flower Extract Alleviates Oxidative Stress and Inflammatory Factors in the Adjuvant-Induced Arthritis Rat Model

INTRODUCTION: This research was to evaluate the beneficial effects of Styphnolobium japonicum (L.) Schott flower extract (SJF) on the adjuvant-induced arthritis rat model. METHODS: Arthritis was evoked by injection of complete Freund’s adjuvant (CFA) in the hind paw. SJF (150 or 300 mg/kg/day) or Celecoxib (5 mg/kg/day) were administered intragastrically from the 0th day to the 28th day. The arthritis symptoms (paw edema, arthritic scores, mechanical hyperalgesia, and thermal hyperalgesia), inflammation biomarkers (RT and CRP), related enzymes (MMP1 and MMP13), oxidative stress markers (CAT, SOD, GPx, and MDA), and inflammatory cytokines (IL-6, IFN-γ, TNF-α, and IL-1β) of SJF-treated CFA rats were evaluated. RESULTS: CFA rats exhibited severe arthritis symptoms, increased oxidative stress, and inflammatory cytokines. Interestingly, SJF treatment relieving arthritis symptoms and restored body weight gain compared with those in the CFA group. SJF treatment decreased the levels of CRP, RF, MMP1, and MMP13 in the CFA group. Besides, SJF treatment increased the activities of antioxidant enzymes and decreased the MDA content and inflammatory cytokines compared with those in the CFA group. Moreover, SJF could increase the mRNA expression of GPx-1 and CAT and inhibit the mRNA expression of IL-6 and TNF-α in the ankle tissue of CFA rats.