Brevi-inflammin: novel actinobacterial COX-2 inhibitor for alleviating rheumatoid arthritis inflammation.

Studies on microbial natural products have increased to explore new therapeutic agents with improved potential. This study introduces Brevi-inflammin, an alkylated flavonoid purified from Brevibacterium casei VRK 1, as a potent anti-inflammatory agent for the treatment of rheumatoid arthritis inflammation. The in vitro anti-inflammatory activity of Brevi-inflammin was assessed through LPS-induced hydrogen peroxide scavenging in RAW 264.7 cell lines. The safety of Brevi-inflammin was evaluated with an acute oral toxicity test. Additionally, its anti-inflammatory effects were analyzed using carrageenan-induced paw edema and complete Freund's adjuvant-induced arthritis. Postural stability was also assessed. The anti-arthritic effects were measured by analyzing C-reactive protein, rheumatoid factor, hematological parameters, as well as liver and kidney function tests. Examination of radiological, histopathological analyses, and oxidative stress markers was carried out. Furthermore, quantitative real-time PCR was performed to evaluate the downregulation of the COX-2 gene. Brevi-inflammin showed hydrogen peroxide scavenging activity at 1000 µg/mL. Toxicity results indicated that Brevi-inflammin was non-toxic up to 2000 mg/kg, with no observed mortality. It also reduced acute inflammation (P < 0.001) and improved postural stability in CFA-induced rats (P < 0.01). Markers of chronic inflammation, such as C-reactive protein (P > 0.05) and rheumatoid factor (P < 0.01), decreased significantly. It also improved hematological, liver, and kidney markers in post-treatment. Radiological and histopathological examinations revealed a reduction in inflammation. Oxidative stress markers SOD (P > 0.05) and GPX (P > 0.05) decreased. The COX-2 gene was downregulated, confirming its anti-inflammatory effect. These findings suggest Brevi-inflammin as a promising candidate for rheumatoid arthritis-mediated inflammation.