In vitro and animal studies have shown that silymarin’s hepatoprotective effects may be attributed to its antioxidant properties and its ability to inhibit the formation of free radicals, particularly those derived from toxic substances like alcohol. Silymarin acts by binding to free radical species, preventing them from damaging organs and tissues. Silymarin also regulates cell membrane permeability by interfering with lipid peroxidation. Additionally, silymarin may act as an iron chelator (i.e., a substance that binds tightly to iron ions, inactivating them), and it appears to increase the activity of superoxide dismutase, as well as levels of glutathione and glutathione peroxidase, all crucial in reducing oxidative stress.[1][2]
Furthermore, silymarin interferes with the inflammatory system. It regulates levels of pro-inflammatory cytokines while increasing levels of the anti-inflammatory interleukin 10 (IL-10). Studies have also shown its ability to inhibit the activation of nuclear factor kappa B (NF-kB) and the expression of cyclooxygenase-2 (COX-2), both key components in the inflammatory cascade.[1][3]
Finally, some studies have shown that silymarin may prevent the deposition of collagen fibers by decreasing the synthesis of platelet-derived growth factor (PDGF) induced DNA in cells. Moreover, silymarin was associated with a reduction in serum TGF-B (TGF-β) levels, which plays an important role in the pathogenesis of liver fibrosis.[1]