Attempts to isolate the active components of the seed began in 1958. the years later, a research team headed by H.Wagner at the university of Munich was believed to be a single compound.Improved chemical separation methods later revealed that silymarin was not a single component but a complex of chemicals know as flavonolignans. The primary components isolated and structurally characterized from silymarin include silybinin, silydianin and silychristin.
Lots of experiments reported silymarin may be hepatoprotective through a number of mechanisms: antioxidant activity, toxin blockade at the membrane level, enhanced protein synthesis, antifibriotic activity, and possible anti-inflammatory or immunomodulating effects.
      Recently, some scientists support silybin is the highest active component in silymarin. But there are diverse opinions.
The research done by Skottova N shows silybin appeared to be responsible for LDL antioxidant effect in vitro in a concentration-dependent manner. Silychristin and silydianin, other flavonolignans of silymarin, acted rather as pro-oxidants.
      However, Dr Dvorak Z and his group compared the cytoprotective effects upon primary human hepatocytes of silymarin extract and its main flavonolignans. The result shows that the best protection was achieved by silydianin and silychristin, and to a lesser degree by silymarin, whilesilybin and isosilybin were less effective.
      The work of Zuber R shows all flavonolignans displayed dose-dependent activities in treating liver diseases.
Till now, there has not a clear conclusion. The relation among all flavoniligans is competitive or mixed as revealed by double reciprocal. The studies are continuing.