Effect of Echinacea alone or in combination with silymarin in the carbon-tetrachloride model of hepatotoxicity

Echinacea preparations are widely used in the prevention or treatment of upper respiratory tract infections. The present study aimed to investigate the effect of a standardized Echinacea extract in experimentally induced liver toxicity and whether this herb would have a modulating effect on the silymarin-induced hepatoprotection in rats. Liver damage was induced by the administration of carbon tetrachloride (CCl₄). Echinacea extract (18 or 36 mg/kg) alone or combined with silymarin (25 mg/kg), silymarin only (25 mg/kg), or saline (control) was given once daily orally simultaneously with CCl₄ and for 1 week thereafter. Serum alanine aminotransferase (ALT) or aspartate aminotransferase were not significantly changed by treatment with Echinacea, but alkaline phosphatase (ALP) in serum decreased by 23.6% by the extract at 36 mg/kg. Silymarin given in combination with either dose of Echinacea resulted in 34.9% and 57.8% reduction in AST, 42.7% and 58% reduction in ALT and 41% and 60% reduction in ALP, compared with CCl₄ control group. Silymarin alone reduced ALT, AST, and ALP levels by 58.8%, 61.2%, and 62.2%, respectively. Histopathological examination revealed a mild decrease in degenerated hepatocytes after treatment with 36 mg/kg of Echinacea. Noticeable improvement in the liver damage was observed upon the addition of silymarin to Echinacea. A marked decrease of intracellular protein and glycogen staining was evident after the administration of CCl₄. Slight improvement in protein and glycogen staining was noted after 36 mg/kg of Echinacea. Increased hepatic protein and glycogen staining intensity was observed after silymarin and Echinacea co-treatment compared with Echinacea-only treated groups. Silymarin only treatment resulted in more or less normal histopathological and histochemical findings. The present results suggest that administration of Echinacea extract reduces the hepatoprotective effect of silymarin. Such finding is likely to have important clinical significance in patients with hepatic disease on silymarin treatment.