Role of silymarin in the management of non-alcoholic fatty liver disease: Time to clear the mist

Kuhu Roy
2019 Bioactive Compounds in Health and Disease  
Non-alcoholic fatty liver disease (NAFLD) has become a common chronic liver disease, global in nature. Occurring in individuals without a history of significant ethanol consumption, it encompasses a wide spectrum of hepatic disorders. It ranges from simple steatosis, to its advanced form, non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis to even hepatocellular carcinoma. Infact, hepatocellular carcinoma (HCC) can also develop even in the absence of cirrhosis. The prevalence of NAFLD is
more » ... n the rise primarily because of the already prevalent metabolic conditions like insulin resistance, type 2 diabetes, central obesity and dyslipidemia. Therefore, NAFLD is associated with adverse metabolic consequences. Other than the detrimental hepatic outcomes mentioned above, cases of NAFLD have a very high predisposition to cardiovascular disease. Therefore, management of NAFLD is of paramount importance. However, the challenge lies in the fact that there are no approved therapeutic drug regimens for the treatment of NAFLD. Currently, the standard care comprises of treating the underlying co-existing metabolic abnormalities along with a strong focus on lifestyle modification.Under the purview of dietary management of NAFLD, antioxidants have been used as a therapy, going by the fact that oxidative stress is also a risk factor for NAFLD and its advancement. One of the lesser explored antioxidants with respect to NAFLD is silymarin, the bioactive component of milk thistle. Milk thistle (Silybum marianum) is a Mediterranean herb belonging to the Asteraceae/Compositae family. It is postulated that silymarin inhibits the production of pro-inflammatory cytokines and acts against lipid peroxidation by free radical scavenging, thereby it functions as an antioxidant. In addition to that, it is also anti-inflammatory and anti-fibrotic in nature and has membrane stabilizing properties. The bioactive component in milk thistle is a lipophilic extract from it seeds and fruits which is collectively known as silymarin. The collective term 'silymarin' refers to a complex set of flavonolignans; silibin A, silibin B, isosilibin A, isosilibin B, silichristin, isosilichristin, silidianin and a single flavonoid, taxifolin. Among the flavonolignans, silibin is the most biologically relevant component of silymarin, although the biological mechanism is less understood. Treatment with silymarin in cases of fatty liver has shown to improve the hepatic biochemical profile, especially alanine amino transferase. But, the data is very limited in nature and often conflicting. Existing evidence, with its own set of methodological drawbacks, presents a mixed bag of findings that support or refute using silymarin alone or in combination in the management of NAFLD. This review is therefore aimed at clearing the mist surrounding silymarin and its potential in managing NAFLD. Long term studies of multicentric nature are required to better elucidate the dosage, duration, underlying molecular mechanisms, safety and the overall impact in terms of changes in liver histology of silymarin therapy in the management of NAFLD.Keywords: Non—alcoholic fatty liver disease, antioxidants, milk thistle, silymarin, flavonolignans, silibin
doi:10.31989/bchd.v2i5.622 fatcat:2u3tpxshmbbtxh3a6dttwudvp4