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Bratislava, Slovakia

Mucaji P.,Katedra Farmakognozie a Botaniky | Nagy M.,Katedra Farmakognozie a Botaniky | Sersen F.,Comenius University | Svajdlenka E.,Ustav prirodnich leciv | And 3 more authors.
Chemicke Listy | Year: 2012

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 scavenging 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-galactoside (hyperosid), quercetin-3-O-ara-binoside, quercetin 3-0-rutinoside (rutin), kaempferol 3-O-arabinoside and kaempferol 3-O-rutinoside. All of them might be responsible for the observed antioxidant effects.

Kurin E.,Katedra Farmakognozie a Botaniky | Nagy M.,Katedra Farmakognozie a Botaniky
Chemicke Listy | Year: 2012

The review presents the following methods of quantitative analysis of drug interactions: The Loewe additivity model, Bliss independence model, Webb's fractional products method and the Chou model. Therapeutic synergy is achieved by combining drugs to obtain higher benefits which could not be reached with individual drugs. The synergy improves not only the drug effect, but also leads to a dosage decrease at equal or increased efficacy and finally to reduction or delay of drug resistance as well as reduction of toxic effects. In some cases also a small improvement of drug effects without increasing adverse actions means a great clinical shift even without synergy.

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