In vitro anti-inflammatory and anti-oxidative effects of Cinnamomum camphora extracts

Cinnamomum camphora Sieb (Lauraceae) has long been prescribed in traditional medicine for the treatment of inflammation-related diseases such as rheumatism, sprains, bronchitis and muscle pains. In this study, therefore, we aimed to investigate the inhibitory effects of Cinnamomum camphora on various inflammatory phenomena to explore its potential anti-inflammatory mechanisms under non-cytotoxic (less than 100 mu g/ml) conditions. The total crude extract (100 mu g/ml) prepared with 80% methanol (MeOH extract) and its fractions (100 mu g/ml) obtained by solvent partition with hexane and ethyl acetate (EtOAc) significantly blocked the production of interleukin (IL)-1 beta, IL-6 and the tumor necrosis factor (TNF)-alpha from RAW264.7 cells stimulated by lipopolysaccharide (LPS) up to 20-70%. The hexane and EtOAc extracts (100 mu g/ml) also inhibited nitric oxide (NO) production in LPS/interferon (IFN)-gamma-activated macrophages by 65%. The MeOH extract (100 mu g/ml) as well as two fractions (100 mu g/ml) prepared by solvent partition with n-butanol (BuOH) and EtOAc strongly suppressed the prostaglandin E-2 (PGE(2)) production in LPS/IFN-gamma-activated macrophages up to 70%. It is interesting to note that hexane, BuOH and EtOAc extracts (100 mu g/ml) also inhibited the functional activation of beta 1-integrins (CD29) assessed by U937 homotypic aggregation up to 70-80%. Furthermore, EtOAc and BuOH extracts displayed strong anti-oxidative activity with IC50 values of 14 and 15 mu M, respectively, when tested by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and xanthine oxide (XO) assays. Taken together, these data suggest that the anti-inflammatory actions of Cinnamomum camphora may be due to the modulation of cytokine, NO and PGE(2) production and oxidative stress, and of the subtractions tested, the EtOAc extract may be further studied to isolate the active anti-inflammatory principles. (c) 2005 Elsevier Ireland Ltd. All rights reserved.