In vivo cytokine modulatory effects of cinnamaldehyde, the major constituent of leaf essential oil from Cinnamomum osmophloeum Kaneh.

The purpose of this study was to analyse the major compound in the leaf essential oil of Cinnamomum osmophloeum Kaneh. and to examine its in vivo toxicity and cytokine-modulatory effects. The HS-GC/MS and quantitative HPLC analyses showed the concentrations of the major compounds, cinnamaldehyde, benzaldehyde and 3-phenylpropionaldehyde, in the leaf essential oil of Cinnamomum osmophloeum to be 16.88, 1.28 and 1.70 mg/mL, respectively. Acute and sub-acute toxicity tests identified no significant changes in body weight, liver and kidney function indices, and pathology for the mice treated with up to 1 mL/kg body weight of Cinnamomum osmophloeum leaf essential oil or up to 4 mg/kg body weight of cinnamaldehyde. A murine model was established using ovalbumin (OVA)-primed Balb/C mice treated with various concentrations of Cinnamomum osmophloeum leaf essential oil or cinnamaldehyde daily for 4 weeks. The results of tests with commercial ELISA kits indicated no significant cytokine-modulatory effects in mice treated with Cinnamomum osmophloeum leaf essential oil; however, the serum concentrations of IL-2, IL-4 and IL-10, but not IFN-γ, significantly increased in animals treated with 1 mg/kg body weight of cinnamaldehyde during the 4-week period. The possibility that the other constituents act as antagonists of cinnamaldehyde cannot be excluded.