Salazinic Acid-Derived Depsidones and Diphenylethers with α-Glucosidase Inhibitory Activity from the Lichen Parmotrema dilatatum
Asshaima Paramita Devi, Thuc‐Huy Duong, Solenn Ferron, Mehdi A. Beniddir, Minh-Hiep Dinh, Van‐Kieu Nguyen, Nguyen‐Kim‐Tuyen Pham, Dinh Hung Mac, Joël Boustié, Warinthorn Chavasiri, Pierre Le Pogam
Abstract
Abstract Three new depsidones, parmosidones F – G (1 – 2), and 8′-O-methylsalazinic acid (3), and 3 new diphenylethers, parmetherines A – C (4 – 6), together with 2 known congeners were isolated from the whole thalli of Parmotrema dilatatum, a foliose chlorolichen. Their structures were unambiguously determined by extensive spectroscopic analyses and comparison with literature data. The isolated polyphenolics were assayed for their α-glucosidase inhibitory activities. Newly reported benzylated depsidones 1 and 2 in particular inhibited α-glucosidase with IC50 values of 2.2 and 4.3 µM, respectively, and are thus more potent than the positive control, acarbose.