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

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

Povzetek

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.

Ključne besede

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;

Podatki

Jezik:	Angleški jezik
Leto izida:	2005
Tipologija:	1.01 - Izvirni znanstveni članek
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
UDK:	66.061:547.9:543.635
COBISS:	9016342
ISSN:	0308-8146
Matična publikacija:	Food chemistry
Št. ogledov:	1884
Št. prenosov:	102
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarne ključne besede:	kemijska procesna tehnika;ekstrakcija;rastlinski materiali;vsebnost fenolnih komponent;hidroliza;antioksidanti;flavoni;flavonoli;proantocianidini;olja;emulzije;
URN:	URN:SI:UM:
Strani:	str.191-198
Letnik:	ǂVol. ǂ89
Zvezek:	ǂiss. ǂ2
Čas izdaje:	2005
ID:	8718452