Isolation and structure elucidation of the major individual polyphenols in carob fibre

• Verfasst von: Owen, Robert [VerfasserIn]
• Verfasst von: Haubner, R. [VerfasserIn]
• Verfasst von: Hull, William Edmund [VerfasserIn]
• Verfasst von: Erben, G. [VerfasserIn]
• Verfasst von: Spiegelhalder, Bertold [VerfasserIn]
• Verfasst von: Bartsch, Helmut [VerfasserIn]
• Verfasst von: Haber, B. [VerfasserIn]
• Titel: Isolation and structure elucidation of the major individual polyphenols in carob fibre
• Verf.angabe: R.W. Owen, R. Haubner, W.E. Hull, G. Erben, B. Spiegelhalder, H. Bartsch, B. Haber
• E-Jahr: 2003
• Jahr: 29 August 2003
• Umfang: 12 S.
• Fussnoten: Gesehen am 23.11.2020
• Titel Quelle: Enthalten in: Food and chemical toxicology
• Ort Quelle: New York, NY [u.a.] : Elsevier, 1982
• Jahr Quelle: 2003
• Band/Heft Quelle: 41(2003), 12, Seite 1727-1738
• ISSN Quelle: 1873-6351
• DOI: doi:10.1016/S0278-6915(03)00200-X
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: Antioxidants
• Sach-SW: Carob fibre
• Sach-SW: Flavonoids
• Sach-SW: HPLC
• Sach-SW: Mass spectrometry
• Sach-SW: Mediterranean diet
• Sach-SW: NMR
• Sach-SW: Polyphenols
• K10plus-PPN: 1740425901

Abstract

Although it is already known that carob fibre contains several classes of polyphenolic substances, a comprehensive analysis of these has not been conducted to date. Therefore, the major polyphenolic compounds were extracted with organic solvents, and, following fractionation by normal-phase column chromatography on silicic acid, their structures were elucidated by liquid-chromatography electrospray-ionisation mass spectrometry (LC-ESI), nano-electrospray-ionisation mass spectrometry (ESI-MS), and gas-chromatography mass spectrometry (GC-MS). In addition, complete 1H and 13C NMR assignments were obtained for the isolated gallotannins 1,6-di-, 1,2,6-tri- and 1,2,3,6-tetra-O-galloyl-β-d-glucose. Carob fibre was found to contain a rich variety of phenolic antioxidants. A total of 24 polyphenol compounds were identified with a yield of 3.94 g/kg (dry weight). The profile was dominated by gallic acid in various forms: free gallic acid (42% of polyphenols by weight), gallotannins (29%), and methyl gallate (1%), while simple phenols, mainly cinnamic acid, made up about 2% of the total. Flavonoids represented 26% of the polyphenols, and the major components were identified as the glycosides myricetin- and quercetin-3-O-α-l-rhamnoside (ca. 9% and 10%, respectively). These data indicate that carob fibre is rich in both amount and variety of phenolic antioxidant substances, and its inclusion in the diet may have chemopreventive properties.