Protective effect of crude extract from Wedelia paludosa (Asteraceae) on the hepatotoxicity induced by paracetamol in mice.

Several in-vitro and in-vivo ethnopharmacological studies carried out with plants of the genus Wedelia have already demonstrated hepatoprotective effects in chemically-induced liver injury, including those induced by paracetamol. Here, the effects of the crude extract from Wedelia paludosa on paracetamol-induced hepatotoxicity in mice was investigated. Intraperitoneal injection of paracetamol (1,000 mg kg(-1)) caused 80% death after 24 h in mice, which was significantly reduced by oral pretreatment with W. paludosa (500 mg kg(-1)). Hepatotoxicity was observed 24 h after an intraperitoneal injection of paracetamol (600 mg kg(-1)), as evidenced by an increase in plasma activity of aspartate and alanine aminotransferases. That hepatotoxicity was significantly attenuated by W. paludosa pretreatment (100-500 mg kg(-1)) in a dose-response manner. Paracetamol (1,000 mg kg(-1)) drastically depleted total glutathione levels and decreased glutathione peroxidase and delta-aminolevulinate dehydratase activity in the liver, such effects not being prevented by pretreatment with W. paludosa. Neither paracetamol treatment alone nor pretreatment with W. paludosa altered glutathione reductase and glutathione S-transferase activity or the levels of end-products of lipid peroxidation. In conclusion, we found that W. paludosa protected against paracetamol-induced hepatotoxicity, an effect not observed over oxidative stress-related parameters. Hepatoprotection is likely mediated by some terpenes present in W. paludosa extract. However, further studies will be required to explain the mechanisms involved in the hepatoprotection afforded by W. paludosa.