Essential Oil from Eucalyptus benthamii Maiden et Cambage Reduces Nitric Oxide Production in Lipopolysaccharide-induced Murine Peritoneal Macrophages

Few studies are concerned about the essential oil extracted from leaves of Eucalyptus benthamii Maiden et Cambage that shows high content of alpha-pinene. The goal of this paper was to investigate the in vitro effect of the essential oil of E. benthamii and alpha-pinene on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in mouse peritoneal macrophages. Macrophages were harvested by washing with phosphate buffered saline and cultured with 10 mu g/mL LPS. Three concentrations (5, 10, and 20 mu g/mL) of the essential oil of E. benthamii and alpha-pinene were investigated. Nitrite levels were measured based on the Griess reaction, an indirect assay for NO production. The essential oil of E. benthamii significantly suppressed NO production in murine peritoneal macrophages at 10 and 20 mu g/mL. In contrast, alpha-pinene did not inhibit NO production.