Inhibition of Polyphenol Oxidase by Quercetin Derivatives in Grape Skin

• Tohru Okuda ^[1] ; Emiko Kawai ^[1] ; Jun Harada ^[1] ; Eri Inoue ^[1] ; Masashi Hisamoto ^[1] ; Fumie Watanabe-Saito ^[1]
  1. [1] University of Yamanashi

     University of Yamanashi

     Japón

     
• Localización: American Journal of Enology and Viticulture, ISSN 0002-9254, Vol. 70, Nº 1, 2019, págs. 109-113
• Idioma: inglés
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• Resumen

  • Polyphenol oxidase (PPO) inhibitors were isolated from grape skin and identified as quercetin derivatives. Among the inhibitors isolated, quercetin-3-glucoside (Q3Glc) was the most potent. Kinetic analysis of the inhibitory activity toward PPO was carried out with authentic Q3Glc using catechol as substrate. The inhibition was reversible, the inhibitory mechanism obtained from Lineweaver-Burk plots indicated that Q3Glc is a competitive inhibitor, and the inhibitory constant (Ki) was 84.6 µM.