What is silymarin and why is it mentioned in the description of milk thistle? — Sea buckthorn seeds 50g Horst (semena rastoropshi) (семена расторопши)

The card lists silymarin among the components of milk thistle seeds (along with vitamins, micro- and macroelements), of which, according to the description, there are about 200. What silymarin is, how much of it is in the seeds and what effect is attributed to it, the card does not explain.

General information (not a manufacturer's instruction): a herbal infusion does not replace treatment; in case of diseases a doctor's consultation is needed.