Effects of Salvia sclarea on chronic immobilization stress induced endothelial dysfunction in rats

BACKGROUND Although Salvia sclarea (clary sage) is widely used in aromatherapy and has antioxidant and antimicrobial properties, its mechanisms of action remain poorly understood. We therefore assessed whether clary sage is effective in treating endothelial dysfunction induced by chronic immobilization stress in rats. METHODS Rats were intraperitoneally injected with almond oil, clary sage oil (5%, 10% or 20%), or nifedipine once daily, followed by immobilization stress (2 h/day) for 14 days. Systolic blood pressure (SBP) and heart rate (HR) were measured, as were serum concentrations of corticosterone (CORT); a biomarker of chronic stress, malondialdehyde (MDA); a biomarker of oxidative stress. Nitric oxide production was assessed by nitrite assays, and eNOS level, a biomarker of endothelial dysfunction, was measured by western blotting. Endothelial dysfunction was also assayed by measuring the effect of clary sage on the contraction of rat aortae. RESULTS Treatment with 5% (p = 0.029), 10% (p = 0.008), and 20% (p = 0.008) clary sage significantly reduced SBP and treatment with 20% clary sage significantly reduced HR (p = 0.039) compared with the chronic immobilization stress group. Clary sage decreased CORT serum concentration (10%, p = 0.026; 20%, p = 0.012) and MDA (10%, p = 0.007; 20%, p = 0.027), findings similar to those observed with nifedipine. In addition, 20% clary sage significantly increased nitric oxide production (p <0.001) and eNOS expression level (p <0.001) and relaxed aortic rings in rats subjected to chronic immobilization stress. CONCLUSIONS Clary sage treatment of rats subjected to immobilization stress contributed to their recovery from endothelial dysfunction by increasing NO production and eNOS level as well as by decreasing oxidative stress. Appropriate concentration of clary sage may result in recovery from endothelial dysfunction. These findings indicate that clary sage oil may be effective in the prevention and treatment of stress-induced cardiovascular diseases.