Progress in the research of chemical structural modification of ursolic acid and structure-activity relationship

Ursolic acid，a pentacyclic triterpene compound，naturally occurs in a large variety of plants，has attracted considerable interest owing to its significant biological activities.In recent years，more and more scientists have been working on the structural modification at the C-3 position ，C₁₂-C₁₃ double bond or C-28 position of ursolic acid in order to improve their biological activities.Herein a brief introduction of the recent progresses on the chemical structural modification and the structure-activity relationship of ursolic acid and its derivatives are reviewed.