Two-Phase Flavonoid Formation in Developing Strawberry (Fragaria × ananassa) Fruit

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• 作者：Heidrun Halbwirth ; Iva Puhl ; Ursula Haas ; Karoline Jezik ; Dieter Treutter ; and Karl Stich
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2006
• 出版时间：February 22, 2006
• 年：2006
• 卷：54
• 期：4
• 页码：1479 - 1485
• 全文大小：158K
• 年卷期：v.54,no.4(February 22, 2006)
• ISSN：1520-5118

文摘

Flavonoids are important secondary metabolites in strawberry as they fulfill a wide variety ofphysiological functions. In addition, they are beneficial for human health. Previous studies have shownfor selected enzymes from the flavonoid pathway that flavonoid biosynthesis shows two peaks duringfruit development. We provide optimized protocols for the determination of the activities of the keyflavonoid enzymes: phenylalanine ammonia lyase, chalcone synthase/chalcone isomerase, flavanone3-hydroxylase, dihydroflavonol 4-reductase, flavonol synthase, flavonoid 3-O-glucosyltransferase, andflavonoid 7-O-glucosyltransferase. Using these protocols we were able to demonstrate two distinctactivity peaks during fruit ripening at early and late developmental stages for all enzymes with theexception of flavonol synthase. The first activity peak corresponds to the formation of flavanols, whilethe second peak is clearly related to anthocyanin and flavonol accumulation. The results indicatethat flavonoid 3-O-glucosyltransferase activity is not essential for redirection from flavanol toanthocyanin formation in strawberry.Keywords: Strawberry (Fragaria × ananassa); fruit ripening; fruit color; flavonoid concentrations;flavonoid enzymes; anthocyanins; flavan 3-ols (catechin, epicatechin, and derived proanthocyanidins);flavonols