ORIGINAL ARTICLE The Sesquiterpene Lactone, Budlein A, Inhibits Antigen-Induced Arthritis in Mice: Role of NF-κB and Cytokines Ana C. Zarpelon, 1 Victor Fattori, 1 Fabricio O. Souto, 2 Larissa G. Pinto, 2 Felipe A. Pinho-Ribeiro, 1 Kenji W. Ruiz-Miyazawa, 1 Walter M. Turato, 2 Thiago M. Cunha, 2 Fernando B. da Costa, 3 Fernando Q. Cunha, 2 Rubia Casagrande, 4 Nilton S. Arakawa, 4 and Waldiceu A. Verri Jr 1,5,6 Abstract— Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by debilitating pain, cartilage destruction, and loss of joint function. Management of RA includes drugs that target NF-κB and downstream cytokine production. Therefore, molecules that act by inhibiting this signaling pathway without the severe side effects of, for instance, corticoids would be suitable therapeutic strategies. Budlein A is a sesquiterpene lactone with antinociceptive and anti-inflammatory properties related to the inhibition of pro- inflammatory cytokines and neutrophil recruitment. In this study, the effect of budlein A was evaluated in antigen-induced arthritis (AIA) in mice. At the 26th day, leukocyte recruit- ment to the knee joint, knee contents of proteoglycans, blood levels of ALT and AST, stomach tissue myeloperoxidase activity, and RT-qPCR for pro-inflammatory gene mRNA expression in knee joint samples was performed. NF-κB luciferase activity was evaluated in RAW 264.7 macrophages. Budlein A treatment dose-dependently inhibited AIA-induced mechanical hyperalgesia, edema, total leukocytes and neutrophil recruitment, and proteoglycan degrada- tion. Budlein A did not induce gastric or liver damage. Budlein also inhibited AIA-induced Il- 33, Tnf, Il-1β, preproET-1, and Cox-2 mRNA expression. In vitro, budlein reduced TNF- and IL-1β-induced NF-κB activity in RAW 264.7 macrophages. Altogether, we demonstrate that budlein A ameliorates AIA-induced inflammation and pain by targeting NF-κB. Importantly, budlein A does not induce in vivo side effects, suggesting that it possesses a favorable pre- clinical profile as analgesic and it is a prosperous molecule to be further investigated for the treatment of RA. KEY WORDS: antigen-induced arthritis; articular pain; experimental arthritis; inflammation; rheumatoid arthritis. Ana C. Zarpelon and Victor Fattori contributed equally. 1 Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rod. Celso Garcia Cid PR 445, Km 380 Cx. Postal 10.011, Londrina, Parana 86051-990, Brazil 2 Department of Pharmacology, Ribeirão Preto Medical School, Preto, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14049-900, Brazil 3 Department of Pharmaceutical Sciences, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14049-900, Brazil 4 Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Estadual de Londrina, Londrina, Paraná 86038-350, Brazil 5 Departamento de Patologia, Centro de Ciências Biologicas, Universidade Estadual de Londrina, Rod. Celso Garcia Cid Pr 445, KM 380, Cx. Postal 10.011, Londrina, Parana 86057-970, Brazil 6 To whom correspondence should be addressed at Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rod. Celso Garcia Cid PR 445, Km 380 Cx. Postal 10.011, Londrina, Parana 86051-990, Brazil. E-mail: waldiceujr@yahoo.com.br 0360-3997/17/0000-0001/0 # 2017 Springer Science+Business Media, LLC Inflammation ( # 2017) DOI: 10.1007/s10753-017-0642-1