Effect of silymarin on biochemical indicators in patients with liver disease: Systematic review with meta-analysis

AIM: To evaluate the effect of silymarin on the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma glutamyl transpeptidase (γGT) in patients with liver diseases. METHODS: A systematic review with meta-analysis of ramdomized and controlled clinical trials was performed, evaluating the effects of sylimarin in patients with hepatic diseases, published by January 31, 2016. Clinical trials were sought on the basis of The Cochrane Central Register of Controlled Trials in the Cochrane Library, PubMed/Medline, Scopus, Web of Science, Lilacs and Clinical Trials. The trials with adult and elderly patients of both sexes, with Liver Diseases who took oral silymarin supplementation, as extract or isolated, as well as Silymarin combined with other nutrients, were included. The trials should provide information about the intervention, such as dosages and detailing of the product used, besides the mean and standard deviation of serum levels of ALT, AST and γGT of the baseline and at the end of the intervention. RESULTS: An amount of 10904 publications were identified. From those, only 17 were included in the systematic review and 6 in the meta-analysis, according to the used selection criteria. In this meta-analysis, the results indicated a reduction of 0.26 IU/mL (95%CI: -0.46-0.07, P = 0.007) at the level of ALT and 0.53 IU/mL (95%CI: -0.74-0.32, P = 0.000) at the serum levels of AST after using the silymarin, both, statistically significant, but with no clinical relevance. There was no significant change in the γGT levels. Subgroup analyzes were also performed for the biochemical markers in relation to the type of intervention, whether silymarin isolated or associated with other nutrients and the time of intervention (whether ≥ 6 mo or < 6 mo). Significant differences were not found. The evaluated studies presented a high degree of heterogeneity and low methodological quality in the carried out analysis. CONCLUSION: Silymarin minimally reduced, but without clinical relevance, the serum levels of ALT and AST. It is necessary to carry out studies with more appropriate methodological designs.