Usneaceratins A and B, two new secondary metabolites from the lichen .

Two new compounds, comprising one dibenzofuran, named usneaceratin A (), and one phenolic acid, named usneaceratin B (), together with one known dibenzofuran, isousnic acid (), and two known phenolics, orsellinic acid () and methyl orsellinate () were clarified from the lichen using variously chromatographic methods. Their structures were testified by comprehensive HR-ESI-MS, and NMR spectroscopic analysis, and comparison with published data. Their -glucosidase inhibitory activity of all compounds was measured. Usneaceratin B () possessed better inhibition against -glucosidase enzyme (IC value of 41.8 μM) than the standard drug acarbose (IC value of 214.50 μM).