Protective effect of carnosol on CCl4-induced acute liver damage in rats

Background We recently reported that Rosmarinus officinalis (Lamiaceae) may alleviate CCl4-induced acute hepatotoxicity in rats, possibly blocking the formation of free radicals generated during CCl4 metabolism. Carnosol, one of the main constituents of Rosmarinus, has been shown to have antioxidant and scavenging activities. Therefore, it is plausible to expect that carnosol may mediate some of the effects of Rosmarinus on oxidative stress consequences induced by CCl4 in the liver. Design We evaluated the effectiveness of carnosol to normalize biochemical and histological parameters of CCl4-induced acute liver injury. Methods Male Sprague Dawley rats (n = 5) injured by CCl4 (oral dose 4 g/kg of body weight) were treated with a single intraperitoneal dose (5 mg/kg) of carnosol. Twenty-four hours later, the rats were anaesthetized deeply to obtain the liver and blood, and biochemical and histological parameters of liver injury were evaluated. Results Carnosol normalized bilirubin plasma levels, reduced malondialdehyde (MDA) content in the liver by 69%, reduced alanine aminotransferase (ALT) activity in plasma by 50%, and partially prevented the fall of liver glycogen content and distortion of the liver parenchyma. Conclusions Carnosol prevents acute liver damage, possibly by improving the structural integrity of the hepatocytes. To achieve this, carnosol could scavenge free radicals induced by CCl4, consequently avoiding the propagation of lipid peroxides. It is suggested that at least some of the beneficial properties of Rosmarinus officinalis are due to carnosol.