title: Evaluation of antioxidative activity of extracts from a brown seaweed, Sargassum siliquastrum.
abstract: Antioxidative activities of the extracts from Sargassum siliquastrum were determined using the inhibition of red blood cell (RBC) hemolysis induced by 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) radicals, suppression of lipid peroxidation using rat brain homogenate, and scavenging activity of superoxide radicals. The dichloromethane fraction isolated from the methanol crude extract by differential solvent extractions exhibited the strongest antioxidant activity in both RBC hemolysis and lipid peroxidation assays. This fraction was further fractionated into four subfractions F1-F4 by silica gel column chromatography. F1 was found to be most effective in protecting RBC against AAPH radicals and in inhibiting lipid peroxidation. On the basis of thin-layer chromatography and UV and IR spectra analyses, all subfractions contained phenolic compounds. However, there was no correlation between the above antioxidant potency and total phenolic compounds estimated by using the Folin-Ciocalteau method.
authors.affiliation: Department of Biology, The Chinese University of Hong Kong, Shatin, New Territories, People's Republic of China.
authors.forename: S N
authors.initials: SN
authors.lastname: Lim
authors.forename: P C K
authors.initials: PC
authors.lastname: Cheung
authors.forename: V E C
authors.initials: VE
authors.lastname: Ooi
authors.forename: P O
authors.initials: PO
authors.lastname: Ang
mesh_terms: D000578:Amidines / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology; D001923:Brain Chemistry; D005591:Chemical Fractionation; D002855:Chromatography, Thin Layer; D005296:Ferrous Compounds / Q000494:pharmacology; D005609:Free Radicals; D006461:Hemolysis / Q000187:drug effects; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008752:Methylene Chloride; D000459:Phaeophyceae / Q000737:chemistry; D010636:Phenols / Q000032:analysis / Q000302:isolation & purification; D051381:Rats; D017207:Rats, Sprague-Dawley; D012624:Seaweed / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000578:Amidines; D000975:Antioxidants; D005296:Ferrous Compounds; D005609:Free Radicals; D010636:Phenols; D008752:Methylene Chloride; C046728:2,2'-azobis(2-amidinopropane); D001205:Ascorbic Acid