Isolation and characterization of alkyl peroxy radical scavenging compound from leaves of Laurus nobilis.
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.
Kang
Hye Won
HW
Graduate School of Biotechnology, Korea University, Sungbuk-Gu, Seoul.
Yu
Kwang Won
KW
Jun
Woo Jin
WJ
Chang
Ih Seop
IS
Han
Sang Bae
SB
Kim
Hee Yun
HY
Cho
Hong Yon
HY
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
D002241:Carbohydrates; D005419:Flavonoids; D044948:Flavonols; D016166:Free Radical Scavengers