Brazilin isolated from Caesalpinia sappan L. inhibits rheumatoid arthritis activity in a type-II collagen induced arthritis mouse model

BACKGROUND: Caesalpinia sappan L. extracts exhibit great therapeutic potential, and have been shown to have analgesic and anti-inflammatory properties. This study aimed to understand the anti-rheumatoid activity of brazilin that was isolated from ethyl acetate extract of C. sappan L. The evaluations were conducted in mice with type-II collagen-induced arthritis (CIA). METHODS: Brazilin was purified via preparative HPLC and identified by mass spectrometry and (1)H/(13)C NMR analysis. DBA/1J mice were divided into four groups (n = 10). Three groups of mice received intradermal injections of inducer bovine type-II collagen (BTIIC; 2 mg/ml in 0.05 ml acetic acid) and 0.1 ml of booster complete Freund’s adjuvant (CFA). A second injection of BTIIC with booster incomplete Freund’s adjuvant (ICFA) was given subsequently after 21 days. On 22nd day, purified brazilin (10 mg/kg body weight) or the disease-modifying anti-rheumatic drug methotrexate (3 mg/kg body weight) was administered intraperitoneally daily or every three days for 21 days, respectively to two groups of mice. At the 42nd day, mice sera were collected, and the levels of pro-inflammatory cytokines and stress enzyme markers in serum were measured using standard immunoassay methods. The microstructure and morphometric analyses of the bones were assessed using high-resolution microfocal computed tomography. RESULTS: Brazilin isolated from C. sappan reduced the arthritis index score and the extent of acute inflammatory paw edema in CIA-mice. The bone mineral density was significantly (p < 0.05) lower in only-CIA mice, and appeared to increase commensurate with methotrexate and brazilin administration. Brazilin prevented joint destruction, surface erosion, and enhanced bone formation as revealed by microstructural examinations. Brazilin markedly attenuated mouse CIA and reduced the serum levels of inflammatory cytokines including TNF-α, IL-1β, and IL-6. CONCLUSIONS: Brazilin purified from C. sappan L. shows protective efficacy in CIA mouse, and may be useful to treat chronic inflammatory disorders including rheumatoid arthritis.