title: Isolation and characterization of alkyl peroxy radical scavenging compound from leaves of Laurus nobilis.
abstract: EtOH-soluble fraction from leaves of Laurus nobilis (bay leaves) possessed the highest alkyl peroxy radical (ROO*) scavenging activity among 120 kinds of herbs and edible plants, using the bioassay system which could determine the viability of Staphylococcus aureus 209p by ROO* cytotoxicity. After EtOH-soluble fraction was partitioned with chloroform, ethylacetate, n-butanol and water, the ethylacetate-soluble fraction (L-EA) possessing the highest scavenging activity was further fractionated by Silica gel, Sephadex LH-20 and semi-preparative HPLC analysis on micro-Bondapak C18 reverse phase, and a major flavonol (L-EA-IIa-3-H2) in leaves of L. nobilis was isolated. According to the ultraviolet-visible absorption spectra, L-EA-IIa-3-H2 was thought to be 3,5,7,3'-OH or 3(5),7,3',4'-OH flavonol. After acid hydrolysis of the fraction, L-EA-IIa-3-H2 was found to consist of quercetin and glucose, and was confirmed by one- or two-dimensional (1D or 2D)-NMR to be isoquercitrin. In addition, the ROO* scavenging activity of L-EA-IIa-3-H2 was supported by ESR and its activity was found to be comparable to that of other well-known antioxidants such as epigallocatechin and resveratrol, and higher than that of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and ascorbic acid.
authors.affiliation: Graduate School of Biotechnology, Korea University, Sungbuk-Gu, Seoul.
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Kang
authors.forename: Kwang Won
authors.initials: KW
authors.lastname: Yu
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Jun
authors.forename: Ih Seop
authors.initials: IS
authors.lastname: Chang
authors.forename: Sang Bae
authors.initials: SB
authors.lastname: Han
authors.forename: Hee Yun
authors.initials: HY
authors.lastname: Kim
authors.forename: Hong Yon
authors.initials: HY
authors.lastname: Cho
mesh_terms: D002241:Carbohydrates / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D005419:Flavonoids / Q000737:chemistry / Q000302:isolation & purification; D044948:Flavonols; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification; D008401:Gas Chromatography-Mass Spectrometry; D027442:Laurus / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D018515:Plant Leaves / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002241:Carbohydrates; D005419:Flavonoids; D044948:Flavonols; D016166:Free Radical Scavengers