AUTHOR=Hao Yi-Meng , Yan Yuan-Cong , Zhang Qing , Liu Bing-Qian , Wu Chang-Sheng , Wang Li-Ning 

TITLE=Phytochemical composition, antimicrobial activities, and cholinesterase inhibitory properties of the lichen Usnea diffracta Vain

JOURNAL=Frontiers in Chemistry

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.1063645

DOI=10.3389/fchem.2022.1063645

ISSN=2296-2646

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