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Yifei Wang, Stephanie K. Fong, Ajay P. Singh, Nicholi Vorsa, and Jennifer Johnson-Cicalese

( Kalt et al., 2007 ). The flavonoid compounds are believed to be the most relevant constituents contributing to blueberry’s health benefits. The most abundant classes of blueberry flavonoids are the anthocyanins, flavonols, and proanthocyanidins (PACs

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Gregor Osterc, Maja Mikulic Petkovsek, Franci Stampar, Biljana Kiprovski, Blanka Ravnjak, and Joze Bavcon

equal measurement conditions. Extraction of phenolic compounds. For flavonols and anthocyanin quantification, the leaf laminas and flowers were ground to a fine powder with liquid nitrogen. Then 0.5 g of powder was extracted with 2 mL methanol containing

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John J. Sheahan and Garry A. Rechnitz

Depietion of the ozone layer is increasing the amount of UV-B radiation reaching the earths surface. The enhanced aging and mutation associated with UV-B damage suggests that crop yields may be threatened. However, plants are protected by flavonols which absorb UV-B. Although a great deal of research has been done on the flavonols, progress has been hampered by their lack of color. To overcome this problem, a staining procedure that provided sensitive and specific fluorescence identification of flavonols in Arabidopsis thaliana was developed. Three T-DNA insertional mutants, which lacked flavonols were identified, and the heritability of each has been confirmed by its multiple occurance in the parental line. The Mutants are being outcrossed, and analysis of the F2 will test if any of the mutations are tagged by a T-DNA insert. If so, the tagged gene will then be cloned.

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Ninghang Wang, Chao Zhang, Sainan Bian, Pengjie Chang, Lingjuan Xuan, Lijie Fan, Qin Yu, Zhigao Liu, Cuihua Gu, Shouzhou Zhang, Yaling Wang, and Yamei Shen

). Natural biological flavonoids are derivatives of their basic structures, and they often exist in the form of glycosides ( Heiss et al., 2010 ). The different structural flavonoids can be divided into 10 types, including anthocyanin, flavone, flavonol

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Justine E. Vanden Heuvel and Wesley R. Autio

). Flavonoids can further be classified into smaller subgroups such as anthocyanins, flavonols, and proanthocyanindins. Little information exists concerning the development of secondary metabolites in cranberry fruit. There are variations in the flavonoid

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Jan Bizjak, Nika Weber, Maja Mikulic-Petkovsek, Ana Slatnar, Franci Stampar, Zobayer Alam, Karl Stich, Heidi Halbwirth, and Robert Veberic

, which accumulate as granules in the vacuoles ( Bae and Kim, 2006 ), but flavonols (quercetin 3- O -glycosides) and proanthocyanidins also have some influence ( Lister et al., 1994 ). Anthocyanin accumulation is usually restricted to the skin of apple

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Valentina Schmitzer, Maja Mikulic-Petkovsek, Franci Stampar, and Vlasta Cunja

, carotenoids, chlorophylls, and flavonols are the major contributors to astonishing color diversity of flowers, and their content often changes during flower senescence ( Schmitzer et al., 2010 ; Slatnar et al., 2013 ; Sood and Nagar, 2003 ). Moreover, petal

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Vlasta Cunja, Maja Mikulic-Petkovsek, Franci Stampar, and Valentina Schmitzer

et al., 2010 , 2012 ). However, research on rose leaf polyphenols is still partial and scarce. Different authors report total phenolic content, total flavonoid, or total flavonol aglycone levels in leaf extracts ( Ghazghazi et al., 2012 ; Nowak and

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Kevin A. Lombard, Emmanuel Geoffriau, and Ellen B. Peffley

Because of potential benefits on human health, the content of quercetin, the major flavonol found in onion (Allium cepa), could become a selection trait in breeding programs. Total flavonol concentration in onion was examined by spectrophotometric analysis at 374 nm in three long-day hybrid cultivars grown at three locations (Parma, Idaho; Grand Rapids, Mich; Elba, N.Y.), and in three shortday hybrid cultivars grown at one location in Georgia in three different fields. Mean total flavonol concentrations for long-day hybrids ranged from 176 to 232 mg·kg-1 (ppm) fresh weight and 110 to 173 mg·kg-1 fresh weight among short-day cultivars. No significant effect of location (state or field) was detected (P > 0.05). A significant (P > 0.05) cultivar by field interaction was detected in the short-day experiment, with the hybrid `Sweet Vidalia' showing significant differences among fields. Overall, our results suggest that quercetin content in onion, as expressed by the total flavonol content, does not vary depending on the growing origin, and therefore could be evaluated effectively in breeding or commercial material.

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Olanike O. Onayemi, Catherine C. Neto, and Justine E. Vanden Heuvel

The effect of partial defoliation (rate and timing) on vine carbohydrate concentration and the development of phenolic compounds in field-grown `Stevens' cranberry fruit was investigated in two experiments. In Expt. 1, partial defoliation rates of 0%, 18%, 39%, and 53% of total leaf area were applied before new growth, at fruit set, at midfruit development, and preharvest. In Expt. 2, treatments of 0% and 34% removal of new leaves were applied at postfruit set, and at midfruit development. In both experiments, upright samples were harvested for carbohydrate analysis 10d after defoliation, and fruit were removed for analysis before commercial harvest of the site. While total berry phenolic concentration was unaffected by partial defoliation in both studies, the separate pools of flavonoid compounds were affected differently by treatment. In Expt. 1, total flavonol concentration at harvest was improved by the highest rate of partial defoliation (53% of total leaf area) at both fruit set and midfruit development. Total anthocyanin concentration was improved by partial defoliation rates of 39% and 53% of total leaf area compared to the 18% defoliation treatment, but was not affected by timing of defoliation. Pearson correlation coefficients indicated that total flavonol concentration was positively correlated with vine total nonstructural carbohydrate concentration at preharvest, while total anthocyanin concentration was negatively correlated with vine soluble carbohydrates, starch, and total nonstructural carbohydrate concentration at midfruit development. In Expt. 2, total phenolics, flavonols, and anthocyanins were unaffected by partial defoliation; however there was a negative correlation between total anthocyanin concentration in the fruit and soluble carbohydrate concentration in the vine at midfruit development. In these experiments, partial defoliation early in the growing season improved total flavonols and total anthocyanins. Production of flavonols and anthocyanins appeared to be regulated independently of each other.