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Silymarin, a standardised extract of Silybum marianum (milk thistle), comprises mainly of silybin, with dehydrosilybin (DHSB), quercetin, taxifolin, silychristin and a number of other compounds which are known to possess a range of salutary effects. Indeed, there is evidence for their role in reducing tumour growth, preventing liver toxicity, and protecting a number of organs against ischemic damage. The hepatoprotective effects of silymarin, especially in preventing Amanita and alcohol intoxication induced damage to the liver, are a well established fact. Likewise, there is weighty evidence that silymarin possesses antimicrobial and anticancer activities. Additionally, it has emerged that in animal models, silymarin can protect the heart, brain, liver and kidneys against ischemia reperfusion injury, probably by preconditioning. The mechanisms of preconditioning are, in general, well studied, especially in the heart. On the other hand, the mechanism by which silymarin protects the heart from ischemia remains largely unexplored. This review, therefore, focuses on evaluating existing studies on silymarin induced cardioprotection in the context of the established mechanisms of preconditioning. [ABSTRACT FROM AUTHOR]

A recent study showed that silymarin, a standardized extract of S. marianum might be used in the prevention of equine laminitis. We investigated the effects of quercetin and some compounds found in silymarin (silybin, taxifolin and dehydrosilybin) on reactive oxygen species (ROS) production and myeloperoxidase (MPO) release by stimulated equine neutrophils (PMNs) and on MPO activity. All compounds (tested between 100 n m and 100 μ m) inhibited superoxide anion production by stimulated PMNs in a dose-dependent manner. Dehydrosilybin and quercetin inhibited superoxide production and MPO release from 10 μ m. Classical MPO assay showed quercetin as the most potent inhibitor, followed by taxifolin, dehydrosilybin and silybin. SIEFED MPO assay highlighting the binding of tested compounds to MPO showed that only quercetin and taxifolin maintained an efficient inhibition above 90% at 10 μ m. Altogether, our results showed a strong inhibition of PMN activation by planar compounds such as quercetin and dehydrosilybin and a strong inhibition of MPO activity by the smallest molecules, quercetin and taxifolin. In conclusion, the compounds from silymarin may be useful for modulating the oxidative response of PMNs, involved in the pathogenesis of laminitis, but further in vivo studies are needed. [ABSTRACT FROM AUTHOR]

The aims of the present study were (1) to determine the cytotoxicity of colchiceine (EIN) in comparison with that of colchicine (COL); (2) to evaluate the effect of EIN on cytochrome P450 (CYP) expression and activity. Primary human hepatocytes were the model of choice for cytotoxicity and CYP expression experiments. LDH leakage and albumin secretion served as cytotoxicity parameters. EIN was less toxic than COL based on both parameters within the concentration range 1–100 μm. 10 μm concentration of EIN did not induce the expression of CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2E1 and CYP3A4 isoforms, which were evaluated at the levels of mRNAs, proteins and specific activities in culture. EIN in concentrations up to 200 μm had no effect on marker activities of CYP1A2, 2C9, 2E1 and 3A4 in human liver microsomes. It was concluded that EIN in concentrations up to 10 μm is not cytotoxic in primary human hepatocytes as revealed by albumin secretion and LDH leakage. Possible drug–drug interactions of EIN due to effects on cytochromes P4501A2, 2C9, 2E1 and 3A4 isoforms are unlikely because inhibition/induction studies show any lack of such effects. As EIN was shown to have better antifibrotic properties than COL (European Journal of Clinical Investigation 1997, 2, 77), it can be used as a COL substitute with anticipated fewer side-effects. [ABSTRACT FROM AUTHOR]