title: Highly brominated mono- and bis-phenols from the marine red alga Symphyocladia latiuscula with radical-scavenging activity.
abstract: Four new highly brominated and fully substituted mono- and bis-phenols, 1-(2,3,6-tribromo-4,5-dihydroxybenzyl)pyrrolidin-2-one (1), 1,2-bis(2,3,6-tribromo-4,5-dihydroxyphenyl)ethane (2), 6-(2,3,6-tribromo-4,5-dihydroxybenzyl)-2,5-dibromo-3,4-dihydroxybenzyl methyl ether (3), and 2,3,6-tribromo-4,5-dihydroxybenzyl methyl sulfone (4), were characterized from the marine red alga Symphyocladia latiuscula. In addition, five known bromophenols, bis(2,3,6-tribromo-4,5-dihydroxyphenyl)methane (5), bis(2,3,6-tribromo-4,5-dihydroxybenzyl) ether (6), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (7), 2,3,6-tribromo-4,5-dihydroxymethylbenzene (8), and 2,3,6-tribromo-4,5-dihydroxybenzaldehyde (9), were also isolated and identified. The structures of these compounds were elucidated by spectroscopic methods including 1D and 2D NMR as well as by low- and high-resolution mass spectrometric analysis. Structurally, all of these compounds are highly brominated and fully substituted, and contain one or two 2,3,6-tribromo-4,5-dihydroxyphenyl unit(s) in each of the molecules. In addition, compound 4 possesses a unique sulfone structural feature. Each of the isolated compounds was evaluated for alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical-scavenging activity and all were found to be potent, with IC50 values ranging from 8.1 to 24.7 microM, compared to the known positive control butylated hydroxytoluene (BHT), with an IC50 of 81.8 microM.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Nanhai Road 7, Qingdao 266071, People's Republic of China.
authors.forename: Xiao-Juan
authors.initials: XJ
authors.lastname: Duan
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Li
authors.forename: Bin-Gui
authors.initials: BG
authors.lastname: Wang
mesh_terms: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D006842:Hydrocarbons, Brominated / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D008386:Marine Biology; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010851:Picrates / Q000494:pharmacology; D000461:Rhodophyta / Q000737:chemistry*
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D006842:Hydrocarbons, Brominated; D010636:Phenols; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl