Advances in studies on oral absorption and metabolism of pentacyclic triterpenoid saponins Advances in studies on pharmacological activities of pentacyclic triterpenoid saponins Advances in studies on three pentacyclic triterpenoids and their derivatives against ADIS Chemical constituents from Paliurus ramosissimus Advances in studies on structural modifications and biological activities of 18β-glycyrrhetinic acid Advances in studies on biosynthesis and regulation of pentacyclic triterpenoid saponin Advances in studies on oral absorption and metabolism of pentacyclic triterpenoid saponins Studies on Chemical Constituents in the Stem and Leaf of Isodon oresbius Advances in studies on structural modifications and biological activities of 18β-glycyrrhetinic acid