Hepatoprotective effects of Hibiscus, Rosmarinus and Salvia on azathioprine-induced toxicity in rats

As an anti-metabolite, Azathioprine inhibits the de novo and salvage pathways of purine synthesis. Intraperitoneal injection of this drug results in not only lymphocyte suppression but also toxicity to bone marrow, gastrointestinal tract, and liver. This Azathioprine-induced hepatotoxicity was found to be associated with oxidative damage. Plants with antioxidative properties have been traditionally used to prevent diseases associated with free radicals. In this report, we used water extracts of three herbal plants that have been commonly used for treating many illnesses (Hibiscus sabdariffa, Rosmarinus officinalis and Salvia officinalis). Here we show their novel hepatoprotective effects against Azathioprine-induced hepatotoxicity in rats. Typically, administration of Azathioprine induces oxidative stress through depleting the activities of antioxidants and elevating the level of malonialdehyde in liver. This escalates levels of alanine aminotransferase, and aspartate aminotranferase in serum. Pretreatment with any of the three herbal plants used in this investigation proved to have a protective effect against Azathioprine-induced hepatotoxicity. Animals pretreated with water extracts from any of the three herbs under investigation not only failed to show necrosis of the liver after azathioprine administration, but also retained livers that, for the most part, were histologically normal. In addition, these herbs blocked the induced elevated levels of alanine aminotransferase and aspartate aminotranferase in serum. The Azathioprine-induced oxidative stress was relieved to varying degrees by the examined herbal extracts. This effect was evident through reducing malonialdehyde levels and releasing the inhibitory effect of Azathioprine on the activities of glutathione, catalase and superoxide dismutase. To our knowledge, this report is the first that shows hepatoprotective effects of Hibiscus, Rosmarinus and Salvia species against Azathioprine-induced acute liver damage. (c) 2005 Elsevier Inc. All rights reserved.