Silymarin has long been used as a hepatoprotective drug, and several studies have confirmed that silymarin has very low toxicity. Silymarin is a new type of flavonoid extracted from the seeds of milk thistle. The main ingredients are silybin, silibinin and silibton. Among them, the highest content of silybin and the strongest biological activity. Basic and clinical studies have confirmed that silybin has the functions of protecting liver, anti-inflammatory, immune regulation, lowering blood fat and anti-oxidation, so it is widely used in the treatment of various liver diseases in countries all over the world.
Pharmacological characteristics of silymarin
Animal experiments have confirmed that silymarin preparation has protective effects against liver damage caused by carbon tetrachloride, galactosamine, alcohols and other hepatotoxins. The hepatoprotective mechanism of silymarin is summarized as follows:
1. Antioxidant effect: Silymarin can protect the hepatocyte membrane by anti-lipid peroxidation, maintain the fluidity of the cell membrane, and also inhibit the release of superoxide anion from neutrophils to reduce hepatocyte damage caused by inflammatory cells. Studies have also shown that silybin can increase the expression of superoxide dismutase (SOD) in lymphocytes in mice with chronic alcoholic liver disease, thereby exerting an antioxidant effect.
2. Anti-inflammatory effects: Silybin can reduce the levels of various pro-inflammatory cytokines such as IL-8, IL-6, MCP-1 and TNF-α, thereby exerting anti-inflammatory effects.
3. Anti-fibrosis: Studies have confirmed that silymarin can achieve anti-fibrosis by anti-oxidation and direct inhibition of activation of hepatic stellate cells (HSC) by various cytokines.
4.Lipid-lowering effect: The mouse experiment confirmed that silybin can reduce the content of triglyceride (TG) and serum TG and total cholesterol (TCh) in the liver. Moreover, the results of these animal experiments also showed that the liver pathology (such as steatosis, inflammation, hepatocyte ballooning) was improved to varying degrees after the intervention of silybin. Studies have also suggested that the drug can reduce the body weight of the test animals.
Silymarin is used in patients with NAFLD
A randomized controlled clinical trial of 64 patients with NASH showed liver biosynthesis in patients who received silymarin 210 mg/d for 8 weeks (n = 33) compared with placebo-treated (n = 31) patients. Significant improvement has been made; the combination of silymarin preparations with metformin, pioglitazone, vitamin E, acyclovir, lovastatin and other drugs can improve insulin resistance and hepatic pathological changes in patients with nonalcoholic fatty liver disease.
Silymarin is used in patients with alcoholic liver
Five clinical trials of silymarin for the treatment of alcoholic liver disease have been published, and more than 600 patients with alcoholic cirrhosis have been included. The 4-year cumulative survival rate of the silymarin treatment group was significantly higher than that of the placebo group (P=0.036) after a mean 41-month treatment, and subgroup analysis suggested silymarin for alcoholic cirrhosis. The efficacy is not related to the severity of liver disease. Milk thistle preparation can effectively treat alcoholic liver disease, which is of great significance for improving the quality of life and prolonging the survival time of patients with alcoholic cirrhosis.
Silymarin is used for chronic viral hepatitis
Studies have shown that patients with chronic hepatitis C are well tolerated and safe with high doses of silybin. Since then, many researchers have used high-dose silybin intravenous injections to prevent recurrence after liver transplantation in HCV-infected patients; these studies have also confirmed that silybin can rapidly reduce HCV viremia and is safe.
The current application of silymarin preparations is mainly focused on liver protection, especially in the adjuvant treatment of NAFLD, ALD and DILI. With the deepening of the research on the pharmacological activity of silybin, silybin has shown good curative effect in reducing blood fat, anti-platelet aggregation, anti-tumor and treating diabetic complications, but it still needs to comply with the principle of evidence-based medicine. Clinical trials to confirm its efficacy.