antiradical activity Dotaz Zobrazit nápovědu
Spektrofotometricky byla metodou změn absorbance difenyl-p-pikrylhydrazylu stanovena schopnost vychytávat volné radikály hydrochloridu (±)-trans-2-(1-pyrrolidinyl-) cyklohexylesteru kyselin3-(n)-pentyloxykarbanilové, pentakainu (trapenkain I.N.N.) a jeho derivátu, dále lidokainu, stobadinu, manitolu a kyseliny askorbové. Nejvyšší antiradikálovou aktivitu prokázal trapenkain, vyššínež porovnávací standardy stobadin, kyselina askorbová a manitol. Zavedení methylenu do hydrofilní části molekuly trapenkainu se porovnáním s trapenkainem neukázalo výhodným (stereoiso-mery P-18, P-20), ale cis isomer je antiradikálovi aktivnijší než trans-isomer. Výsledky ukázaly naexistenci vztahu mezi chemickou strukturou, antiradikálovou aktivitou a gastricko-cytoprotektivním účinkem.
The free radical scavenging effect of the hydrochloride of (±)-trans-2-(1-pyrrolidinyl-) cyclohexylesterof 3-(n)-pentyloxy carbanilic acid, pentacaine (trapencaine I.N.N), and its derivatives and othersubstances, lidocaine, stobadine, mannitol, and ascorbic acid was tested in the presence of diphenyl-p-picrylhydrazyl (decrease in absorbance). In this method, more pronounced antiradical activitywas observed with trapencaine, more effective than stobadine, ascorbate, and mannitol. Trapen-caine derivatives and lidocaine were less effective in comparison with trapencaine. After introducinga methylene group into the hydrophilic moiety of the trapencaine molecule (stereoisomers P-18,P-20), there was a loss of antiradical activity, but the cis-isomer is more effective than thetransisomer. The results demonstrate the existence of relationships between the chemical structure,antiradical and gastric-cytoprotective activity.
Po objevení antioxidační ochrany biologických systémů se volné radikály a jejich účinky staly předmětem intenzivního výzkumu v procesu různých typů onemocnění. Práce je zaměřena na studium antiradikálové aktivity látek ze skupiny heteroarylethanolaminů. Místem působení těchto látek je kardiovaskulární systém, kde mohou vznikat endotelové dysfunkce, probíhá oxidace cholesterolu aj. Vysoce reaktivním volným radikálem je oxid dusnatý (NO.), vznikající endogenně působením enzymu NO-syntasy (NOS). Hlavním rozkladným produktem vodného roztoku oxidu dusnatého jsou dusitany, které se v přítomnosti hemoproteinů oxidují až na dusičnany. Základní metodou detekce oxidačních produktů oxidu dusnatého je Griessova metoda založená na spektrofotometrickém stanovení dusitanů po diazotaci sulfanilamidu a kopulaci s N-(1-naftyl)-etylendiaminem s detekcí v oblasti při 540 nm. Antioxidanty, látky, které organismus využívá k neutralizaci některých volných radikálů, reagují na principu oxidace – redukce. Pro průkaz antioxidační aktivity byla zvolena metoda bromometrie. V bromometrii po reakci bromidu a bromičnanu vzniká elementární brom, který je vlastním oxidačním činidlem. Tento vzniklý brom se může, v našich laboratorních podmínkách, považovat za „volný radikál“ schopný oxidovat další systémy. Na tomto modelu lze stanovit, jak velkou antioxidační kapacitu má sledovaná látka. Obě metody byly porovnány s metodou pro hodnocení antiradikálové aktivity pomocí stabilního radikálu 2,2- difenyl-1-pikrylhydrazylu (DPPH).
After the discovery of the antioxidant protection of biological systems, free radicals and their effects became the subject of intensive research in the process of various types of diseases. The paper focuses on the study of antiradical activity of substances from the group of heteroarylethanolamines. The site of action of these substances is the cardiovascular system, where endothelial dysfunctions may develop, oxidation of cholesterol takes place, etc. A highly reactive free radical is dinitrogen oxide (NO.), developing endogenously by the action of NO-synthase (NOS) enzyme. The principal disintegration product of an aqueous solution of nitrogen oxide are nitrites, which in the presence of hemoproteins oxidize to produce nitrates. The principal method of detection of the oxidative products of nitrogen oxide is the Griess method based on spectrophotometric determination of nitrites after diazotation of sulfanilamide and copulation with N-(1-naphthyl)-ethylene diamine with detection in the region at 540 nm. Antioxidants, substances which the organism uses to neutralize some free radicals, react on the principle of oxidation–reduction. The method of bromometry was selected to demonstrate antioxidative activity. In bromometry, the reaction of bromide and bromate gives rise to elementary bromine, which is the oxidative reagent itself. This developed bromine may, under our laboratory conditions, be considered to be “a free radical” capable of oxidizing other systems. This model makes it possible to determine how large the antioxidative capacity of the substance under study is. Both methods were compared with the method for the evaluation of antiradical activity by means of the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH).
The protective constituents of silymarin, an extract from Silybum marianum fruits, have been extensively studied in terms of their antioxidant and hepatoprotective activities. Here, we explore the electron-donor properties of the major silymarin flavonolignans. Silybin (SB), silychristin (SCH), silydianin (SD) and their respective 2,3-dehydroderivatives (DHSB, DHSCH and DHSD) were oxidized electrochemically and their antiradical/antioxidant properties were investigated. Namely, Folin-Ciocalteau reduction, DPPH and ABTS(+) radical scavenging, inhibition of microsomal lipid peroxidation and cytoprotective effects against tert-butyl hydroperoxide-induced damage to a human hepatocellular carcinoma HepG2 cell line were evaluated. Due to the presence of the highly reactive C3-OH group and the C-2,3 double bond (ring C) allowing electron delocalization across the whole structure in the 2,3-dehydroderivatives, these compounds are much more easily oxidized than the corresponding flavonolignans SB, SCH and SD. This finding was unequivocally confirmed not only by experimental approaches, but also by density functional theory (DFT) calculations. The hierarchy in terms of ability to undergo electrochemical oxidation (DHSCH~DHSD>DHSB>SCH/SD>SB) was consistent with their antiradical activities, mainly DPPH scavenging, as well as in vitro cytoprotection of HepG2 cells. The results are discussed in the context of the antioxidant vs. prooxidant activities of flavonolignans and molecular interactions in complex biological systems.
- MeSH
- antioxidancia farmakologie MeSH
- buňky Hep G2 MeSH
- cytoprotekce * MeSH
- elektronová paramagnetická rezonance MeSH
- flavonolignany chemie farmakologie MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- silymarin farmakologie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Paulownia tomentosa is a large indecidous tree planted mostly for its fast growing wood and decorative purposes. The tree is also used in traditional Chinese medicine. As a part of our study of natural polyphenols, the fruits of Paulownia tomentosa were extracted by EtOH and than subjected to liquid/liquid extraction. Fractions were analysed by TLC and HPLC to determine presence of phenolic substances. We identified and quantified acteoside (1) and isoacteoside (2) in the EtOAc and n-BuOH extracts; mimulone (3) and diplacone (4) in the MeOH extract. To determine the antiradical activity of extracts we used the anti DPPH and peroxynitrite assays. The activity was expressed as Trolox C equivalents, IC50 for DPPH scavenging and a time dependency course was established. The polyphenols content was determined; results were expressed as gallic acid equivalents. Using these methods we found the fractions of the n-BuOH, EtOAc and MeOH extracts that display antiradical activity, which could be exploited as potential pharmaceuticals.
- MeSH
- fenoly farmakologie izolace a purifikace MeSH
- financování organizované MeSH
- flavonoidy farmakologie izolace a purifikace MeSH
- léčivé rostliny MeSH
- léky rostlinné čínské farmakologie izolace a purifikace MeSH
- ovoce chemie MeSH
- rozpouštědla MeSH
- scavengery volných radikálů farmakologie izolace a purifikace MeSH
- stromy MeSH
The in vitro antiradical activity of Schisandra chinensis lignans was investigated using DPPH, ABTS+, Fenton reaction inhibition and tyrosine-nitration inhibition assays, as were the in vivo antidiabetic activities of selected lignans in an animal model of alloxan-induced diabetes. Different degrees of antiradical activity were found, depending upon the structural parameters of the tested compounds. Unfortunately, the compounds showed no antidiabetic activity in concentration range tested.
- MeSH
- antioxidancia farmakologie MeSH
- lignany farmakologie MeSH
- modely u zvířat MeSH
- myši inbrední ICR MeSH
- myši MeSH
- rostlinné extrakty farmakologie MeSH
- scavengery volných radikálů farmakologie MeSH
- Schisandra chemie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The objective of this work was to investigate the aqueous and ethanolic extracts of passionflower and the influence of the flavonoids they contain on the antiradical activity by DPPH* and ABTS* + methods. The data show that the Passiflora extract has not only sedative but also antiradical activity. The ethanol extract catches free radicals more effectively than the water extract. The strongest antiradical effect among the investigated flavonoids (chlorogenic acid, hyperosid, isovitexin, caffeic acid, quercetin, luteolin, orentin, rutin, scutelarein, vicenin and vitexin) was predetermined by vicenin, isovitexin and orentin. The antiradical activity increases with the increase of the concentration of the mentioned materials.
- MeSH
- antioxidancia farmakologie chemie MeSH
- jaterní mikrozomy metabolismus MeSH
- játra metabolismus účinky léků MeSH
- krysa rodu rattus MeSH
- oxidace-redukce účinky léků MeSH
- scavengery volných radikálů farmakologie chemie MeSH
- silymarin farmakologie chemie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- MeSH
- antagonisté histaminu H1 farmakologie MeSH
- bromfeniramin farmakologie MeSH
- chlorfeniramin farmakologie MeSH
- feniramin farmakologie MeSH
- financování organizované MeSH
- krev účinky léků MeSH
- lidé MeSH
- luminiscenční měření MeSH
- reaktivní formy kyslíku metabolismus MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
Isoquercitrin, (IQ, quercetin-3-O-β-d-glucopyranoside) is known for strong chemoprotectant activities. Acylation of flavonoid glucosides with carboxylic acids containing an aromatic ring brings entirely new properties to these compounds. Here, we describe the chemical and enzymatic synthesis of a series of IQ derivatives at the C-6″. IQ benzoate, phenylacetate, phenylpropanoate and cinnamate were prepared from respective vinyl esters using Novozym 435 (Lipase B fromCandida antarcticaimmobilized on acrylic resin). The enzymatic procedure gave no products with "hydroxyaromatic" acids, their vinyl esters nor with their benzyl-protected forms. A chemical protection/deprotection method using Steglich reaction yielded IQ 4-hydroxybenzoate, vanillate and gallate. In case ofp-coumaric, caffeic, and ferulic acid, the deprotection lead to the saturation of the double bonds at the phenylpropanoic moiety and yielded 4-hydroxy-, 3,4-dihydroxy- and 3-methoxy-4-hydroxy-phenylpropanoates. Reducing capacity of the cinnamate, gallate and 4-hydroxyphenylpropanoate towards Folin-Ciocalteau reagent was significantly lower than that of IQ, while other derivatives displayed slightly better or comparable capacity. Compared to isoquercitrin, most derivatives were less active in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, but they showed significantly better 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid, ABTS) scavenging activity and were substantially more active in the inhibition oftert-butylhydroperoxide induced lipid peroxidation of rat liver microsomes. The most active compounds were the hydroxyphenylpropanoates.
- MeSH
- estery * chemie MeSH
- hmotnostní spektrometrie MeSH
- molekulární struktura MeSH
- nukleární magnetická rezonance biomolekulární MeSH
- peroxidace lipidů účinky léků MeSH
- quercetin analogy a deriváty analýza chemická syntéza farmakologie MeSH
- scavengery volných radikálů analýza chemická syntéza farmakologie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
