Protective Effects of Silymarin, Alone or in Combination with Chlorogenic Acid and/or Melatonin, Against Carbon Tetrachloride-induced Hepatotoxicity

OBJECTIVE: The aim of this study was to evaluate the hepatoprotective effects of silymarin (SIL), alone and combined with chlorogenic acid (CA) and/or melatonin (ME), using a rat model of carbon tetrachloride (CCl(4))-induced injury. MATERIALS AND METHODS: Hepatotoxicity was induced by a single dose of CCl(4) (1 ml/kg, IP). One day after, rats were received SIL (200 mg/kg) alone or in combination with CA (60 mg/kg) and/or ME (20 mg/kg) for 21 days. RESULTS: SIL significantly decreased serum alanine aminotransferase, inflammatory cytokines, and vascular endothelial growth factor levels. Histological alterations, fibrogenesis, oxidative DNA damage, inflammatory mediators, and caspase-3 activity were significantly attenuated in SIL treated CCl(4)-intoxicated rats. On the other hand, cytochrome P450 2E1 activity showed a significant decrease in the liver of CCl(4)-intoxicated rats, an effect that was reversed following treatment with SIL. All beneficial effects of SIL were markedly potentiated when combined with CA and/or ME. CONCLUSIONS: These data indicate that SIL, alone and combined with CA and/or ME, protected the liver against CCl(4)-induced hepatotoxicity via attenuating inflammation, oxidative DNA damage, apoptosis, and fibrotic changes. The significantly intensified hepatoprotective effects of SIL when combined with both CA and ME suggest a possible synergism. These synergistic effects need to be further confirmed using detailed studies. SUMMARY: Silymarin, chlorogenic acid and melatonin possess in vivo hepatoprotective activity. Silymarin, chlorogenic acid and melatonin attenuate fibrogenesis, oxidative DNA damage, inflammation and apoptosis. Chlorogenic acid and melatonin enhance the hepatoprotective effect of silymarin. Abbreviations used: SIL: silymarin, CA: chlorogenic acid, ME: melatonin, CCl4: carbon tetrachloride, CYP2E1, cytochrome P450 2E1, ALT: alanine aminotransferase, IL-6: interleukin 6, IFN-γ: interferon gamma, VEGF: vascular endothelial growth factor, TNF-α: tumor necrosis factor alpha, CRP: C-reactive protein, 8-OxodG: 8-Oxo-2’-deoxyguanosine, TGF-B1: transforming growth factor beta 1, HSCs: hepatic stellate cells.