- Email: [email protected]
Optimisation of a quantitative method for the determination of catechins in fruits and pulses
THE MODULATORY EFFECT OF PHENOLIC EXTRACTS ON SMOOTH MUSCLE CELL ACTIVITY C. Rodrigue, M. K. Konneh and J. P. Caen Institutdes Vaisseauvet du Sang, H6pital Lariboisiire, Paris, France
ANTIOXIDANT ENZYMES ACTIVITIES AND TRACE ELEMENT CONCENTRATIONS IN ISCIIEMIA-REPERFUSION I.E.Akcil, T.Tug, ZlMseyen. Department of Parhophvsiologv and Deparment of General Sum, Faculty of Medicine, Ankara Vniversi@ Ankara TurAey
The “French paradox” refers to the very low incidence of and mortality rates from ischaemic heart disease that exist in Prance despite the fact that saturated fat intake, serum cholesterol and prevalence of smoking are not lower in France than in other western countries. Polyphenolic compounds derived from differing sources, including wine,
In this study, we investigated the impact of ischemia reperfusion on antioxidant enzymes activities and trace element wncentrations. For this purpose ischemia was initiated by clamping arteria mesemerica superior of Wistar (alhmo)rats for 30 minutes followed by mperfusion for 20 minutes. Immediately after mperfusion, blood samples were taken and examined for red cell wpper-zinc superoxide dismutase (Cu-Zn-SOD), catalase (CAT) and glutathione peroxidase (GPx) activities spectrophotometritally and plasma zinc, wpper and magnesium wncentrations by atomic absorption spectrophotometer. In ischemia-reperfusion group red cell Cu-Zn-SOD activity and plasma zinc and copper wncentrations were increased significantl~O.001) when compared to the wntrol group, however the increases in GPx activity and plasma magnesium concentration not were significant (pM.OS).We also found a significant (p4.Ol)decrease in catalase activity.Free radicals released as a wnsequence of ischemia-reperftrsion caused significant alterations in antioxidant enzymes and in the wncentrations of trace elements
have been shown to possesses potent antioxidant properties, protecting LDL from oxidation and platelets from aggregation. Recently it was found that red wine polyphenolic extracts (RWPE) induced vasorelaxation. We have found that RWPE inhibits DNA synthesis and growth (measured by 3[H]-thymidine incorporation and cell number) of cultured vascular smooth muscle cells derived from rat thoracic aorta. The inhibition of DNA synthesis may involve the inducible nitric oxide synthase pathway, since in the presence of the NOS inhibitor L-NAME, there was a diminution of growth inhibition. Components of this extract, such as catechin, and gallic acid showed some inhibitory effect on cell proliferation but were less potent than the extract. RWPE also inhibited the migration of VSMC’s in a dose dependent manner. These studies suggest that wine derived compounds may serve to modulate SMC proliferation and migration, events which are crucial to the development of atherosclerosis leading to coronary heart disease.
ANTIOXIDANTS IN PROTECTION FROM UVINDUCED DAMAGE R Tyrrell Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK
OPTIMISATION OF A QUANTITATIVE METHOD FOR THE DETERMINATION OF CATECHINS IN FRUITS AND PULSES I. C. W. Arts, P. C. H. Hollman DLO State Institute for Qua&y Control of Agricultural Products (Rikilt-DLO), Wageningen, The Netherlands
Both the UVA (320-380nm) and UVB (290-32Onm) regions of the solar UV spectrum are implicated in photoageing and photocarcinogenesis in humans. UVB usually damages cells and tissues following direct absorption by macromolecules whereas UVA, in addition to penetrating further into tissue, generates active oxygen intermediates and acts by indirect pathways. There is skin W-induced that evidence considerable carcinogenesis in rodents can be mediated by oxidation. Certain topically applied antioxidants (e.g. epigallocatechin gallate, silymarin, tanuic acid) can prevent UVinduced skin damage. Cellular studies indicate that although antioxidant enzymes may contribute to the prevention of cell damage, the most important cellular antioxidant for protection against UV is reduced glutatbione. Basal and UVA-induced levels of expression of several oxidant-activated genes are suppressed as a consequence of both endogenous or added reducing equivalents and by singlet oxygen modulating agents. Furthermore both antioxidants (eg N-acetylcysteine) and iron chelators can modulate UVA-induced gene expression although the nature of the alteration depends on the specific gene/transcription factor under examination.
Catechins are flavonoids, which are present in fruits, pulses, tea and wine. In vivo and in vitro studies have shown potential health effects of catechins. Quantitative data on catechin contents of foods are needed for an epidemiological evaluation of their health effects. We optimized the determination of catechins in two model foods: apple and canned red kidney-beans. Catechins ((+)catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), (-)-epigallocatechin gallate (EGCg)) were separated using gradient reversed phase HPLC and quantified by UV (270 run; EGC, ECg and EGCg) or fluorescence (280-310 nm excitationemission; C and EC) detection. Type (ethanol, methanol or acetone) and concentration (40-100% in water) of extraction solvent influenced catechin yield, whereas extraction time did not. Optimum extraction was attained with 90% methanol for apple and 70% methanol for beans. Yields were reduced by 50% under sub-optimal extraction conditions. Recovery ( 94%), within-run repeatability (l3%), between-run reproducibility (4-9%) and detection limits (0.01-0.29 ug/ml) were satisfactory. With this method we are able to analyse 40 solid food samples a day, without the need for sample clean-up.
268
ANTIOXIDANT ENZYMES ACTIVITIES AND TRACE ELEMENT CONCENTRATIONS IN ISCIIEMIA-REPERFUSION I.E.Akcil, T.Tug, ZlMseyen. Department of Parhophvsiologv and Deparment of General Sum, Faculty of Medicine, Ankara Vniversi@ Ankara TurAey
The “French paradox” refers to the very low incidence of and mortality rates from ischaemic heart disease that exist in Prance despite the fact that saturated fat intake, serum cholesterol and prevalence of smoking are not lower in France than in other western countries. Polyphenolic compounds derived from differing sources, including wine,
In this study, we investigated the impact of ischemia reperfusion on antioxidant enzymes activities and trace element wncentrations. For this purpose ischemia was initiated by clamping arteria mesemerica superior of Wistar (alhmo)rats for 30 minutes followed by mperfusion for 20 minutes. Immediately after mperfusion, blood samples were taken and examined for red cell wpper-zinc superoxide dismutase (Cu-Zn-SOD), catalase (CAT) and glutathione peroxidase (GPx) activities spectrophotometritally and plasma zinc, wpper and magnesium wncentrations by atomic absorption spectrophotometer. In ischemia-reperfusion group red cell Cu-Zn-SOD activity and plasma zinc and copper wncentrations were increased significantl~O.001) when compared to the wntrol group, however the increases in GPx activity and plasma magnesium concentration not were significant (pM.OS).We also found a significant (p4.Ol)decrease in catalase activity.Free radicals released as a wnsequence of ischemia-reperftrsion caused significant alterations in antioxidant enzymes and in the wncentrations of trace elements
have been shown to possesses potent antioxidant properties, protecting LDL from oxidation and platelets from aggregation. Recently it was found that red wine polyphenolic extracts (RWPE) induced vasorelaxation. We have found that RWPE inhibits DNA synthesis and growth (measured by 3[H]-thymidine incorporation and cell number) of cultured vascular smooth muscle cells derived from rat thoracic aorta. The inhibition of DNA synthesis may involve the inducible nitric oxide synthase pathway, since in the presence of the NOS inhibitor L-NAME, there was a diminution of growth inhibition. Components of this extract, such as catechin, and gallic acid showed some inhibitory effect on cell proliferation but were less potent than the extract. RWPE also inhibited the migration of VSMC’s in a dose dependent manner. These studies suggest that wine derived compounds may serve to modulate SMC proliferation and migration, events which are crucial to the development of atherosclerosis leading to coronary heart disease.
ANTIOXIDANTS IN PROTECTION FROM UVINDUCED DAMAGE R Tyrrell Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK
OPTIMISATION OF A QUANTITATIVE METHOD FOR THE DETERMINATION OF CATECHINS IN FRUITS AND PULSES I. C. W. Arts, P. C. H. Hollman DLO State Institute for Qua&y Control of Agricultural Products (Rikilt-DLO), Wageningen, The Netherlands
Both the UVA (320-380nm) and UVB (290-32Onm) regions of the solar UV spectrum are implicated in photoageing and photocarcinogenesis in humans. UVB usually damages cells and tissues following direct absorption by macromolecules whereas UVA, in addition to penetrating further into tissue, generates active oxygen intermediates and acts by indirect pathways. There is skin W-induced that evidence considerable carcinogenesis in rodents can be mediated by oxidation. Certain topically applied antioxidants (e.g. epigallocatechin gallate, silymarin, tanuic acid) can prevent UVinduced skin damage. Cellular studies indicate that although antioxidant enzymes may contribute to the prevention of cell damage, the most important cellular antioxidant for protection against UV is reduced glutatbione. Basal and UVA-induced levels of expression of several oxidant-activated genes are suppressed as a consequence of both endogenous or added reducing equivalents and by singlet oxygen modulating agents. Furthermore both antioxidants (eg N-acetylcysteine) and iron chelators can modulate UVA-induced gene expression although the nature of the alteration depends on the specific gene/transcription factor under examination.
Catechins are flavonoids, which are present in fruits, pulses, tea and wine. In vivo and in vitro studies have shown potential health effects of catechins. Quantitative data on catechin contents of foods are needed for an epidemiological evaluation of their health effects. We optimized the determination of catechins in two model foods: apple and canned red kidney-beans. Catechins ((+)catechin (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), (-)-epigallocatechin gallate (EGCg)) were separated using gradient reversed phase HPLC and quantified by UV (270 run; EGC, ECg and EGCg) or fluorescence (280-310 nm excitationemission; C and EC) detection. Type (ethanol, methanol or acetone) and concentration (40-100% in water) of extraction solvent influenced catechin yield, whereas extraction time did not. Optimum extraction was attained with 90% methanol for apple and 70% methanol for beans. Yields were reduced by 50% under sub-optimal extraction conditions. Recovery ( 94%), within-run repeatability (l3%), between-run reproducibility (4-9%) and detection limits (0.01-0.29 ug/ml) were satisfactory. With this method we are able to analyse 40 solid food samples a day, without the need for sample clean-up.
268