Search results for "Flavan"

Structure-Activity Relations of Flavonoids as Antimutagens Against Cooked Food Mutagens and Nitroarenes in the Salmonella Reversion Assay

1997

When about 60 flavonoids were tested for their antimutagenic potencies against 2-amino-3-methylimidazo [4,5-f]quinoline (IQ) and the nitroarenes 2-nitrofluorene (2-NF), 1-nitropyrene (1-NP), and 3-nitrofluoranthene (3-NFA) in the Salmonella reversion assay, distinct structure-activity relations were detected. With both groups of compounds, flavonoid glycosides were inactive or at best weakly active. Catechins and anthocyanidins, which lack the carbonyl function at C-4 of the flavane nucleus, were inactive. In contrast, chalcones exerted strong antimutagenicity against IQ and the nitroarenes. With respect to IQ, flavonoids of low polarity were the most active compounds: The parent compounds …

Latvijas medus kvalitātes un autentiskuma parametru izvērtējums

2017

Darba literatūras daļā ir dota informācija par medu un tā patēriņu un ražošanu Latvijā un pasaulē, medus viltošanu un kvalitātes parametriem, analītiskās metodes medus kvalitātes rādītāju noteikšanai, šķidruma hromatogrāfijas un masspektrometrijas pielietojums polifenolu analīzē, statistiskās un datu apstrādes metodoloģijas medus ģeogrāfiskās izcelsmes noteikšanai. Darbā ir veiktu flavonoīdu, fenolo skābju, vitamīnu un augu hormonu noteikšanas metodes izstrāde un validācija medū. Pēc tam ar šo metodi ir noteikts medus sastāvs 394 Latvijas medus paraugos un 35 Gruzijas medus paraugos, kas pēc tam savā starpā tiek salīdzināts, izmantojot literatūras datus un galveno komponentu analīzi.

Dietary flavonols and flavan-3ols as modulators of superoxide radicals production: opposite dose-dependent effects

2012

Modulating activity of dietary flavonols and flavan-3ols on the enzymes xanthina oxidase (XO) and mitochondrial superoxide dismutase (Mn-SOD)

2012

Protection by beverages, fruits, vegetables, herbs, and flavonoids against genotoxicity of 2-acetylaminofluorene and 2-amino-1-methyl-6-phenylimidazo…

2002

Abstract Chinese hamster lung fibroblasts, genetically engineered for the expression of rat cytochrome P450 dependent monooxygenase 1A2 and rat sulfotransferase 1C1 (V79-rCYP1A2-rSULT1C1 cells), were utilized to check for possible protective effects of beverages of plant origin, fruits, vegetables, and spices against genotoxicity induced by 2-acetylaminofluorene (AAF) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Antigenotoxic activities of juices from spinach and red beets against AAF could be monitored with similar effectivity by the HPRT-mutagenicity test (IC50=0.64%; 2.57%) and alkaline single cell gel electrophoresis (comet assay; IC50=0.12%; 0.89%) which detects DNA stran…

Mechanisms involved in the chemoprevention of flavonoids

2001

Flavonoids, widespread in edible plants, have been studied extensively for their anticarcinogenic properties. However, only few studies have been done with these constituents being administered by the dietary route. In our research, the effects of feeding rats with flavone, flavanone, tangeretin, and quercetin were investigated on two steps of aflatoxin B1 (AFB1)-induced hepatocarcinogenesis (initiation and promotion). Nonpolar flavonoids such as flavone, flavanone and tangeretin administered through the initiation period, decreased the number of -gamma-glutamyl transpeptidase-preneoplastic foci. In the same conditions of administration, quercetin, a polyhydroxylated flavonoid, showed no pr…

The inhibition by flavonoids of 2-amino-3-methylimidazo[4,5-f]quinoline metabolic activation to a mutagen: a structure-activity relationship study.

1997

The mutagenicity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in Salmonella typhimurium TA98 is inhibited by flavonoids with distinct structure-antimutagenicity relationships (Edenharder, R., I. von Petersdorff I. and R. Rauscher (1993). Antimutagenic effects of flavonoids, chalcones and structurally related compounds on the activity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and other heterocyclic amine mutagens from cooked food, Mutation Res., 287, 261-274). With respect to the mechanism(s) of antimutagenicity, the following results were obtained here. (1) 7-Methoxy- and 7-ethoxyresorufin-O-dealkylase activities in rat liver microsomes, linked to cytochrome P-450-dependent 1A1 and…

Differential Effects of Nonhydroxylated Flavonoids as Inducers of Cytochrome P450 1A and 2B Isozymes in Rat Liver

1996

Flavanone, flavone, and tangeretin differentially affected the activities of cytochrome P540 1A and 2B isozymes in rat liver. Flavone and, to a lesser extent, tangeretin, increased activities of ethoxyresorufin O-deethylase, methoxyresorufin O-demethylase, and pentoxyresorufin O-dealkylase (PROD), whereas flavanone mainly enhanced PROD activity. Immunoblot analysis indicated that flavone and tangeretin increased cytochrome P450 1A1, 1A2, and 2B1,2 forms, whereas flavanone only enhanced the cytochrome P450 2B isozymes. Northern blot study showed that flavone and tangeretin increased the level of the cytochrome P450 1A2 mRNAs. The concentration of the other mRNAs were slightly or not affected…

Ethnobotanical survey and cytotoxicity testing of plants of South-western Nigeria used to treat cancer, with isolation of cytotoxic constituents from…

2010

Abstract Ethnopharmacological relevance There is only scant literature on the anticancer components of medicinal plants from Nigeria, yet traditional healers in the area under study claim to have been managing the disease in their patients with some success using the species studied. Aim of study To document plants commonly used to treat cancer in South-western Nigeria and to test the scientific basis of the claims using in vitro cytotoxicity tests. Methods Structured questionnaires were used to explore the ethnobotanical practices amongst the traditional healers. Methanol extracts of the most common species cited were screened for cytotoxicity using the sulforhodamine B (SRB) assay in both…

Antimutagenic effects of flavonoids, chalcones and structurally related compounds on the activity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and…

1993

Abstract Sixty-four flavonoids were tested for their antimutagenic potencies with respect to IQ in Salmonella typhimurium TA98 and in part also towards MeIQ, MeIQx, Trp-P-2, and Glu-P-1 and in S. typhimurium TA100. Antimutagenic potencies were quantified by the inhibitory dose for 50% reduction of mutagenic activity (ID 50 ). A carbonyl function at C-4 of the flavane nucleus seems to be essential for antimutagenicity: two flavanols and four anthocyanidines were inactive. Again, five isoflavons, except biochanin A, were inactive. Within the other groups of 21 flavones, 16 flavonols and 16 flavanones the parent compounds flavone, flavonol, and flavonone possessed the highest antimutagenic pot…