Phenols, proanthocyanidins, flavones and flavonols in some plant materials and their antioxidant activities

Mojca Škerget (Author), Petra Kotnik (Author), Majda Hadolin Kolar (Author), Andreja Rižner Hraš (Author), Marjana Simonič (Author), Željko Knez (Author)

Abstract

Methanol extracts prepared from five plant materials native to the Mediterranean area, namely olive tree (Olea europaea) leaf, St. John's wort (Hypericum perforatum), hawthorn (Crataegus laevigata), oregano (Origanum vulgare) and laurel leaf (Lauris nobilis), were examined for their phenolic components. Total phenolic content was determined by the Folin-Ciocalteu method. The content of proanthocyanidins in acid-hydrolysed extracts was determined spectrophotometrically. The contents of free flavones (apigenin andluteolin) and flavonols (kaempferol, myricetin and quercetin) were determined by HPLC analysis. The time of hydrolysis of flavones, flavonols andproanthocyanidins was optimised. Antioxidant activities of apigenin, luteolin, kaempferol, myricetin, quercetin and of plant extracts were examined. Antioxidative activities were studied in sunflower oil at 98 °C, by measuring peroxide value, and in an aqueous emulsion system of -carotene and linoleic acid by measuring the absorbance of the sample. Among flavones and flavonols investigated, only myricetin inhibited oxidation of sunflower oil. All other flavones and flavonols showed pro-oxidative activity. Oppositely, in the emulsion system, only apigenin showed pro-oxidative activity while otherflavones and flavonols and plant extracts inhibited oxidation of -carotene.

Keywords

kemijska procesna tehnika;ekstrakcija;rastlinski materiali;vsebnost fenolnih komponent;hidroliza;antioksidanti;flavoni;flavonoli;proantocianidini;olja;emulzije;chemical processing;extraction;plant material;fenolic content;hidrolysis;antioxidants;flavones;flavonols;proanthocyanidines;oils;emulsions;

Data

Language:	English
Year of publishing:	2005
Typology:	1.01 - Original Scientific Article
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
UDC:	66.061:547.9:543.635
COBISS:	9016342
ISSN:	0308-8146
Parent publication:	Food chemistry
Views:	1884
Downloads:	102
Average score:	0 (0 votes)
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Other data

Secondary language:	English
Secondary keywords:	kemijska procesna tehnika;ekstrakcija;rastlinski materiali;vsebnost fenolnih komponent;hidroliza;antioksidanti;flavoni;flavonoli;proantocianidini;olja;emulzije;
URN:	URN:SI:UM:
Pages:	str.191-198
Volume:	ǂVol. ǂ89
Issue:	ǂiss. ǂ2
Chronology:	2005
ID:	8718452