Potent α-glucosidase inhibitors from the lichen Cladonia species from Sri Lanka

Abstract

The discovery of α-glucosidase inhibitors has been actively pursued with the aim to develop therapeutics for the treatment of diabetes and other carbohydrate-mediated diseases. This study focused on the lichen Cladonia sp., which yielded three potent α-glucosidase inhibitors, namely zeorin (1), methyl β-orcinolcarboxylate (2) and methylorsellinate (3) with several fold higher inhibitory activities than those of acarbose, an antidiabetic drug used to manage type II diabetes mellitus and the standard, 1-deoxynojirimycin. Atranorin (4) and lobaric acid (5), the other two metabolites isolated from the lichen did not show any α-glucosidase inhibitory potential. All compounds were identified on the basis of one dimentional (1D) and two dimentional (2D) NMR spectral data and with comparison to reported data.