Isolation and Characterization of a Phenolic Antioxidant from the Pacific Oyster (Crassostrea gigas)

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• 作者：Mitsugu Watanabe ; Hirotoshi Fuda ; Shigeki Jin ; Toshihiro Sakurai ; Futaba Ohkawa ; Shu-Ping Hui ; Seiji Takeda ; Takayuki Watanabe ; Takao Koike ; Hitoshi Chiba
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2012
• 出版时间：January 25, 2012
• 年：2012
• 卷：60
• 期：3
• 页码：830-835
• 全文大小：252K
• 年卷期：v.60,no.3(January 25, 2012)
• ISSN：1520-5118

文摘

Using an oxygen radical absorbance capacity (ORAC) assay, antioxidant activity was detected in the ethanol extract of the Pacific oyster, which was purified by sequential extraction with organic solvents. The ethyl acetate fraction showed the strongest antioxidant activity and was further purified, yielding a single compound [as assessed by thin-layer chromatography (TLC) and reverse-phase high-performance liquid chromatography (HPLC)]. This compound was identified as 3,5-dihydroxy-4-methoxybenzyl alcohol on the basis of ¹H and ¹³C nuclear magnetic resonance (NMR), heteronuclear multiple-bond correlation (HMBC), and electrospray ionization鈥搈ass spectrometry (ESI鈥揗S) spectral analyses, a conclusion that was confirmed by chemical synthesis. The concentration of the compound was 6.7 mg/100 g of whole oyster meat wet weight. This amphiphilic antioxidant retarded the copper-mediated oxidation of low-density lipoproteins (LDLs) and the generation of thiobarbituric acid reactive substances. Furthermore, the compound showed substantial antioxidant activity using the ORAC and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays compared to natural antioxidants. Although the same compound was previously found in brown algae, its presence in other organisms and antioxidant activity are reported here for the first time.

Keywords:

LDL; low-density lipoproteins; ORAC; DPPH; reactive oxygen species; ROS; polyphenol