RESUMO
Three new depsidones, parmosidones Fâ-âG (1â-â2), and 8'-O-methylsalazinic acid (3), and 3 new diphenylethers, parmetherines Aâ-âC (4â-â6), 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.
Assuntos
Líquens , alfa-Glucosidases , Depsídeos , Inibidores de Glicosídeo Hidrolases/farmacologia , Lactonas , Extratos Vegetais/farmacologia , SalicilatosRESUMO
Chemical investigation of the lichen Parmotrema tsavoense led to the isolation of 5 new depsidones, parmosidones Fâ-âJ (1: â-â5: ). These compounds were structurally elucidated using spectroscopic methods including HRESIMS and 2D NMR data. Compounds 1, 3: , and 4: were evaluated for their inhibition of α-glucosidase. All exhibited potent α-glucosidase inhibitory activity with IC50 values ranging from 10.7 to 17.6 µM, which was much lower than that of the positive control acarbose (IC50 449 µM).