Antidiabetic principles of natural medicines. lI. Aldose reductase and α-glucosidase inhibitors from brazilian natural medicine, the leaves of Myrcia multiflora DC. (Myrtaceae): Structures of myrciacitrins I and II and myrciaphenones A and B

Article abstract of DOI:10.1248/cpb.46.113

The methanolic extract and ethyl acetate-soluble portion from a Brazilian natural medicine, the leaves of Myrcia multiflora DC., which has been used as a specific medicine against diabetes, were found to show inhibitory activities on aldose reductase and α-glucosidase and on the increase of serum glucose level in sucrose-loaded rats and in alloxan- induced diabetic mice. From the ethyl acetate-soluble portion, new flavanone glucosides, myrciacitrins I and II, and new acetophenone glucosides, myrciaphenones A and B, were isolated together with several known compounds such as five flavonol glycosides, myricitrin, mearnsitrin, quercitrin, desmanthin-1, and guaijaverin. The structures of new compounds were determined on the basis of physicochemical and chemical evidence. The principal components of this natural medicine including new glucosides, myrciacitrin I and myrciaphenone B, were found to show potent inhibitory activities on aldose reductase and α-glucosidase.