Synthesis of water soluble pentacyclic dihydroxyterpene carboxylic acid derivatives coupled amino acids and their inhibition activities on α-glucosidase.

Pentacyclic dihydroxyterpene carboxylic acid derivatives were obtained by coupling with l-amino acids at C-28 position. Compare to the parent compounds (MA or CA), the derivatives exhibit superior water solubility. Some of the derivatives exhibit a better α-glucosidase inhibitory activity than that of acarbose in the test conditions of ethanol-water solution and DMSO.