Hao_2022_Front.Chem_10_1063645

Lichens are important sources of versatile bioactive compounds. Two new dibenzofurans (1-2), a multi-substituted single benzene ring (3), and two organic acid compounds (4-5) along with 25 known compounds (6-30) were isolated from the lichen Usnea diffracta Vain. Their structures were identified by physicochemical properties and spectral analyses. Compounds 1-30 were tested for inhibitory activities against Staphylococcus aureus, Escherichia coli, and Candida albicans by the disk diffusion method and microdilution assay respectively. Compound 3 showed moderate inhibitory activities against S. aureus and E. coli with the inhibition zone (IZ) of 6.2smm and 6.3smm, respectively. Depside 10 exhibited good activity against S.aureus and C. albicans with 6.6smm and 32 microg/ml, respectively. The acetylcholinesterase inhibitory activities of compounds 1, 2, and 6-8 with the characteristic dibenzofuran scaffold were evaluated var anti-AChE assay and a molecular docking study. Compound 2 could better inhibit AChE at the concentration of 0.3smicromol/ml with a value of 61.07 +/- 0.85%. The molecular docking study also demonstrated that compound 2 had the strongest binding affinity among the five dibenzofurans, and the '-CDOCKER Energy' value was 14.4513skcal/mol.