title: A new depsidone and antibacterial activities of compounds from Usnea undulata Stirton.
abstract: Usnea undulata Stirton (Usneaaceae) is a fruticose lichen used locally in ethnoveterinary medicine to treat mammary infections in cattle while human beings use it for the treatment of wounds in Eastern Cape, South Africa. Bioactivity-guided fractionation of its extracts led to the isolation and characterization of a new depsidone, 2'-O-methylhypostictic acid (8), together with seven known compounds, i.e. methyl β-orsellinate, norstictic acid, menegazziaic acid, (+) usnic acid, hypoconstictic acid, salazinic acid, and galbinic acid. The structures of the compounds were elucidated on the basis of their spectral analysis including homo- and hetero-nuclear correlation NMR experiments (COSY, NOESY, HMQC, and HMBC) and mass spectra as well as by comparison with available data in the literature. The minimum inhibitory concentrations (MICs) values of the compounds against six bacteria were determined. Compound 8 showed inhibitory activity against Bacillus cereus, Bacillus subtilis, and Staphylococcus epidermidis with MICs of 31, 62.5, 62.5 μg/ml, respectively. (+) Usnic acid was most active against B. subtilis, B. cereus, Staphylococcus aureus, and Escherichia coli with MICs of 8, 8, 31, and 31 μg/ml, respectively, while other compounds exhibited moderate activity.
authors: Analytical Research Division, BCSIR Laboratories Dhaka, Bangladesh Council of Scientific and Industrial Research-BCSIR, Dr. Qudrat-i-Khuda Road, Dhanmondi, Dhaka 1205, Bangladesh. nasimsultana2002@yahoo.com
authors: Nasim
authors: N
authors: Sultana
authors: Anthony Jide
authors: AJ
authors: Afolayan
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001409:Bacillus cereus / Q000187:drug effects; D001412:Bacillus subtilis / Q000187:drug effects; D001572:Benzofurans / Q000737:chemistry / Q000302:isolation & purification; D002417:Cattle; D053630:Depsides / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects; D006801:Humans; D007783:Lactones / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D012459:Salicylates / Q000737:chemistry / Q000302:isolation & purification; D013019:South Africa; D013211:Staphylococcus aureus / Q000187:drug effects; D020949:Usnea / Q000737:chemistry*
chemical_list: C569579:2'-O-methylhypostictic acid; D000900:Anti-Bacterial Agents; D001572:Benzofurans; D053630:Depsides; D007783:Lactones; D012459:Salicylates; C553078:norstictic acid; C073339:usnic acid; C000875:depsidone