Abstract: On the basis of flavonoid lead compounds with biological activity,studying the relationship between structures and bioavailability and modifying their structures is an important means of innovation of new drugs.Silybum marianum (L.) Gaertn.has been used for more than 2000 years to treat liver and gallbladder disorders.Silybin,derived from the milk thistle plant,has received considerable attention due to its hepatoprotective,anti-inflammatory and anticancer effects,however,the bioavailability and therapeutic efficiency of silybin is rather limited by its very low solubility.To solve this problem,silybin is modified or altered via various chemical and physical methods by domestic and foreign scholars,and have obtained a certain achievement.In this paper,the chemical modification of silybin and its analogues in recent years are reviewed.

Key words: silybin, analogues, chemical modification, structure-activity relationships