Anti-inflammatory and anti-arthritic activities of 3,4-dihydro-2,2-dimethyl-2H-naphthol[1,2-b]pyran-5,6-dione (β-lapachone)

The purpose of this study was to evaluate the anti-inflammatory and anti-arthritic activities of 3,4-dihydro-2,2-dimethyl-2H-naphthol[1,2-b]pyran-5,6-dione (beta-lapachone; beta-lap) and to elucidate its probable mode of action. Carrageenan-induced paw edema, cell migration evaluation and production of pro-inflammatory cytokines tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and nitric oxide were used for this study. Freund's complete adjuvant (FCA)-induced arthritis was used as a model of chronic inflammation. beta-Lap was tested in doses of 40 and 60 mg/kg, orally. In the paw edema test, the dose of 60 mg/kg gave a higher percentage inhibition of edema (49.3 %) than control. beta-Lap inhibited neutrophil migration and reduced concentrations of TNF-alpha, IL-6 and NO in peritoneal exudates of animals with peritonitis. In the arthritis test, beta-lap inhibited edema and NO production in the serum of treated animals. Significant anti-inflammatory and anti-arthritic activities were observed in animals treated with beta-lap. The effects of beta-lap can be attributed in part to immunomodulation with reduction of pro-inflammatory cytokines and NO.