Inhibition of inducible nitric oxide synthase gene expression (iNOS) and cytotoxic activity of Salvia sclarea L. essential oil

Essential oil obtained from Salvia sclarea L. leaves was tested for hepatoprotective, inducible nitric oxide synthase (iNOS) gene down regulation and cytotoxic activities. Histopathology of liver tissue showed severe inflammation and necrosis after treatment with 1.5 μg lipopolysaccharide (LPS)/30 g body weight of BALB/c mice. A decrease in inflammation was observed with the treatment of different concentrations of essential oil. Necrosis and infiltration of hepatocytes were barely seen at 100 μg of oil. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis showed down regulation of iNOS at transcriptional level. Growth of HeLa cells was inhibited by the oil with an IC50 of 80.69 ± 0.01 μg/mL. Propidium iodide (PI) staining revealed the presence of apoptosis in oil treated cells. The findings indicate that S. sclarea essential oil is a promising natural source which may be useful for herbal medicine preparation.