Silymarin and its main isomer silibinin, respectively, have been shown to possess antioxidant properties thus preventing lipid peroxidation and membrane destruction in cells. In addition, protein biosynthesis and cell regeneration are accelerated in the damaged liver leading to restoration of the liver functions. Certain mushroom toxins are prevented from entering the liver cell by silibinin due to competitive inhibition of receptors at the cell membrane. Intravenous treatment with a soluble silibinin derivative is now an important life-saving factor in the standard therapy of cases of Amanita phalloides poisoning. Finally, it has recently been shown that silymarin inhibits leukotriene production, which explains its anti-inflammatory effect, and that it has an antifibrotic action.
Clinical trials confirm the positive effects found in experimental studies.
Thus, silymarin is nowadays not only the best documented drug for liver therapy but also one of the most intensively investigated plant extracts with known mechanisms of action. Silymarin can provide substantial protection against different stages of UVB-induced carcinogenesis, possibly via its strong antioxidant properties. Clinical testing of its usefulness is warranted. Treatment with silymarin may also reduce the lipoperoxidation of cell membranes and insulin resistance, significantly decreasing endogenous insulin overproduction and the need for exogenous insulin administration.