Phenolic Metabolites of Karwinskia humboldtiana Leaves

  • P. Mučaji Department of Pharmacognosy and Botany, Faculty of Pharmacy, Comenius University, Bratislava,
  • M. Nagy Department of Pharmacognosy and Botany, Faculty of Pharmacy, Comenius University, Bratislava,
  • F. Šeršeň Institute of Chemistry, Faculty of Natural Sciences, Comenius University Bratislava,
  • E. Švajdlenka Institute of Natural Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno,
  • J. Drozd Institute of Natural Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno,
  • M. Štujber Department of NMR and MS Spectroscopy, Faculty of Chemical and Food Technology, Slovak Technical University, Bratislava
  • T. Liptaj Department of NMR and MS Spectroscopy, Faculty of Chemical and Food Technology, Slovak Technical University, Bratislava

Abstrakt

Methanolic extract from leaves of Karwinskia humboldtiana (Schult.) Zucc. was subjected to fractionation with a pair of immiscible solvents and subsequently tested for antioxidant activity. Using DPPH the order of scaven¬ging activities of the extracts in comparison with standards of L-ascorbic acid and quercetin was as follows: ethyl acetate fraction > L-ascorbic acid > quercetin > butan-1-ol > light petrol > chloroform > water. The capability of scavenging OH radicals determined by EPR was as follows: ethyl acetate, chloroform > light petrol > butan-1-ol > water fractions. On the basis of availability and antioxidant activity of these fractions, isolation of constituents from butanol fractions was achieved. Separation of this fraction led to the isolation of (+)-epicatechin and flavonol derivatives quercetin, quercetin 3-O-glucoside (isoquercitrin), quercetin-3-O-galac¬toside (hyperosid), quercetin-3-O-ara¬binoside, quercetin 3-O-rutinoside (rutin), kaempferol 3-O-arabinoside and kaempferol 3-O-rutinoside. All of them might be responsible for the observed antioxidant effects.
Publikované
2013-01-15
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