• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.919-927
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• 2018

To compare the antioxidant properties and flavonols in various parts; dry skin (DS) and edible portion (EP), of 8 red onions (Allium cepa L, ROs), total content of phenolics (TPC), flavonoids (TFC), and anthocyanins (TAC) and DPPH radical scavenging properties were estimated and the content of six flavonols were quantified by HPLC-PDA analysis. The major component of DS and EP of RO was quercetin and quercetin-4'-glucoside, respectively. Score plots of the PCA and PLS-DA were segregated by flavonols content and antioxidant properties according to the EP and DS of ROs. Loading plot of the PCA showed that the quercetin and sum of flavonol content were highly correlated with antioxidant activity of ROs. Therefore, flavonol content and antioxidant activity can be used as markers for distinct parts of ROs.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.16-22
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• 2015

Alkaloids of Vinca minor L. were characterized by HPLC equipped with the photo diode array detector and compared their UV/vis absorption spectra with an index material such as vincamine. UV/vis absorption spectra of more than 9 compounds belong to various classes such as flavonoids were shown and characterized. Extracts with ethanol or hot water were tested against the DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical to investigate their antioxidant activity. Based on the results, those extracts show about 14-15% of antioxidant activity of quercetine and vitamin C used as standards.