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Hydroxycinnamic Acids (hydroxycinnamic + acid)
Selected AbstractsHydroxycinnamic Acids as DNA-Cleaving Agents in the Presence of CuII Ions: Mechanism, Structure,Activity Relationship, and Biological ImplicationsCHEMISTRY - A EUROPEAN JOURNAL, Issue 46 2009Gui-Juan Fan Abstract The effectiveness of hydroxycinnamic acids (HCAs), that is, caffeic acid (CaA), chlorogenic acid (ChA), sinapic acid (SA), ferulic acid (FA), 3-hydroxycinnamic acid (3-HCA), and 4-hydroxycinnamic acid (4-HCA), as pBR322 plasmid DNA-cleaving agents in the presence of CuII ions was investigated. Compounds bearing o -hydroxy or 3,5-dimethoxy groups on phenolic rings (CaA, SA, and ChA) were remarkably more effective at causing DNA damage than the compounds bearing no such groups; furthermore, CaA was the most active among the HCAs examined. The involvement of reactive oxygen species (ROS) and CuI ions in the DNA damage was affirmed by the inhibition of the DNA breakage by using specific scavengers of ROS and a CuI chelator. The interaction between CaA and CuII ions and the influence of ethylenediaminetetraacetic acid (EDTA), the solvent, and pH value on the interaction were also studied to help elucidate the detailed prooxidant mechanism by using UV/Vis spectroscopic analysis. On the basis of these observations, it is proposed that it is the CaA phenolate anion, instead of the parent molecule, that chelates with the CuII ion as a bidentate ligand, hence facilitating the intramolecular electron transfer to form the corresponding CaA semiquinone radical intermediate. The latter undergoes a second electron transfer with oxygen to form the corresponding o -quinone and a superoxide, which play a pivotal role in the DNA damage. The intermediacy of the semiquinone radical was supported by isolation of its dimer from the CuII -mediated oxidation products. Intriguingly, CaA was also the most cytotoxic compound among the HCAs toward human promyelocytic leukemia (HL-60) cell proliferation. Addition of exogenous CuII ions resulted in an effect dichotomy on cell viability depending on the concentration of CaA; that is, low concentrations of CaA enhanced the cell viability and, conversely, high concentrations of CaA almost completely inhibited the cell proliferation. On the other hand, when superoxide dismutase was added before, the two stimulation effects of exogenous CuII ions were significantly ameliorated, thus clearly indicating that the oxidative-stress level regulates cell proliferation and death. These findings provide direct evidence for the antioxidant/prooxidant mechanism of cancer chemoprevention. [source] Influence of phenolic acids on growth and inactivation of Oenococcus oeni and Lactobacillus hilgardiiJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2003F.M. Campos Abstract Aims: To determine the effect of several wine-associated, phenolic acids on the growth and viability of strains of Oenococcus oeni and Lactobacillus hilgardii. Methods and Results: Growth was monitored in ethanol-containing medium supplemented with varying concentrations of hydroxybenzoic acids (p -hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acids) and hydroxycinnamic acids (p -coumaric, caffeic and ferulic acids). Progressive inactivation was monitored in ethanol-containing phosphate buffer supplemented in a similar manner to the growth experiments. Hydroxycinnamic acids proved to be more inhibitory to the growth of O. oeni than hydroxybenzoic acids. On the other hand, some acids showed a beneficial effect on growth of Lact. hilgardii. p- Coumaric acid showed the strongest inhibitory effect on growth and survival of both bacteria. Conclusions: Most phenolic acids had a negative effect on growth of O. oeni, for Lact. hilgardii this effect was only noted for p- coumaric acid. Generally, O. oeni was more sensitive to phenolic acid inactivation than Lact. hilgardii. Significance and Impact of the Study: Eight wine-derived, phenolic acids were compared for their effects on wine lactic acid bacteria. Results indicate that phenolic acids have the capacity to influence growth and survival parameters. The differences found between phenolic compounds could be related to their different chemical structures. [source] Analytical methodologies for quantification of ferulic acid and its oligomersJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2008Hélène Barberousse Abstract Ferulic acid (4-hydroxy-3-methoxycinnamic acid) is the most widespread hydroxycinnamic acid in the plant world, where it is a key molecule in cell wall architecture. Owing to its high antioxidant properties, ferulic acid shows large potential applications in food industry as well as in the health and cosmetic markets. There is thus a high interest in extracting this high-value compound from waste materials of the agricultural industry, which requires the selection of an appropriate quantification method. This paper therefore gives an overview of analytical methodologies developed over past decades for quantification of ferulic acid and its oligomers. Copyright © 2008 Society of Chemical Industry [source] Phenolic compounds, lycopene and antioxidant activity in commercial varieties of tomato (Lycopersicum esculentum)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2002Isabel Martínez-Valverde Abstract Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as flavonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p -coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were significantly influenced by the tomato variety. Quercetin, the most abundant flavonoid, was found in concentrations ranging between 7.19 and 43.59,mg,kg,1 fresh weight, while naringenin levels were lower than 12.55,mg,kg,1. The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32,mg,kg,1 fresh weight, followed by caffeic acid, while p -coumaric and ferulic acids showed similar concentrations lower than 5,mg,kg,1. The highest content of lycopene was found in Ramillete, Pera and Durina (>50,mg,kg,1 fresh weight), while the concentration in the other varieties was between 50 and 30,mg,kg,1, with the exception of Liso (less than 20,mg,kg,1). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be significantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid. © 2002 Society of Chemical Industry [source] Effect of water treatment on analyte and matrix ion yields in matrix-assisted time-of-flight secondary ion mass spectrometry: the case of insulin in and on hydroxycinnamic acidRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 21 2002Wilfried Szymczak A systematic study was performed to identify the origin of surprisingly high analyte-to-matrix yield ratios recently observed in time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis of oligo- and polypeptides mixed in matrices of ,-cyano-4-hydroxycinnamic acid (4HCCA). Several sets of samples of porcine insulin in 4HCCA (1:3100 molar) were prepared from liquid solutions by a nebuliser technique, with more than one order of magnitude variation in sprayed material (substrate silicon). Following different periods of storage in air and/or vacuum as well as exposure to high-purity water, TOF-SIMS analysis was performed under oblique impact of 22 keV SF5+. Treatment with water involved either deposition of a droplet covering the whole sample for times between 1 and 20,min or spraying with water in droplet equivalent quantities. The analyte and matrix molecules were detected as protonated molecules (insulin also in doubly protonated form). Even the as-prepared samples usually showed insulin-to-4HCCA yield ratios exceeding the molar ratio of the mixed material. Upon ageing in vacuum the matrix ion yields remained constant but the analyte yields decreased, partly due to break-up of intrachain disulfide bonds. Water treatment resulted in a pronounced decrease in the 4HCCA yield, typically by a factor of five, in parallel with an increase of the insulin yield, by up to a factor of four. Evidence is provided that these changes occur concurrently with a partial dissolution of 4HCCA at the sample surface. The enhanced insulin yield was not correlated with the Na+ yield. The typically 20-fold increase in the insulin-to-4HCCA yield ratio, generated by water exposure of the samples, provides the explanation for the high yield ratios observed previously with water-treated samples. Spraying with water or repeated exposure to water droplets caused a pronounced degradation of the insulin parent yields in combination with an increasing appearance of signals due to the B- and A-chains of insulin. To clarify the issue of surface segregation, a few samples were prepared by spraying acetone-diluted solutions of insulin on previously deposited layers of 4HCCA. Whereas the insulin yields from as-prepared samples were rather low, the yields observed after water treatment were comparable with those observed with samples of insulin in 4HCCA. The results suggest that a large amount of insulin is present at the surface of samples prepared from liquid mixtures of insulin in 4HCCA. With both methods of sample preparation, however, high secondary ion yields of insulin were only obtained after exposure of the samples to water. The chemical changes responsible for this beneficial effect still need to be identified. Copyright © 2002 John Wiley & Sons, Ltd. [source] Conjugated polyamines and hydroxycinnamic acids in grape berries during Botrytis cinerea disease development: differences between ,noble rot' and ,grey mould'AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2003L. GENY Abstract Data are provided on contrasting levels of different categories of polyamines and hydroxycinnamic acids during the course of disease development due to Botrytis cinerea on ripe grape berries that led to either noble rot or to grey mould. Noble rot development was mainly characterised by a greater accumulation of wall-bound polyamines at the beginning of infection, whereas the disease process that led to grey mould was marked by an increase of conjugated polyamines. During grey mould infection, coumaric acid was the predominant hydroxycinnamic acid present in both healthy and infected grape berries regardless of infection stage, whereas ferulic acid was present at lower concentrations than the other hydroxycinnamic acids identified. Moreover, changes in the relative proportions of each of the three hydroxycinnamic acids considered showed contrasting patterns according to the sort of rot which developed. The different roles of these compounds (hydroxycinnamic acids and polyamines) and their involvement in the interaction between Botrytis cinerea and grapevines is discussed. During development of grey mould, coumaric acid was the predominant hydroxycinnamic acid at the beginning and the end of infection, whereas caffeic acid predominated during mid stage. [source] Low molecular weight analysis of tears using matrix assisted laser desorption ionization-time of flight mass spectrometryCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 3 2000Irene Mulvenna BSc ABSTRACT Many low molecular weight substances in human tears, including protein and lipid species, have yet to be characterized. Some of these uncharacterized substances may well be important in the pathogenesis of ocular surface disease or in ocular discomfort. The aim of this study was to build a biochemical profile of low molecular weight species in tears, and to determine its repeatability. A total of 80 tear samples were collected from 11 subjects. Tear samples were dialysed to remove salts, added to a matrix of ,-cyano-4- hydroxycinnamic acid, and analysed using matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. Species were separated based on their mass to charge ratio (m : z). The repeatability of the appearance of the different species was analysed using logistic regression and diurnal and day-to-day repeatability were ascertained. Peptides were identified in the range of 848,3897 Da. Of these, 39 peptides were found to be present in more than 10 / 80 samples. There was no diurnal variation in the peptides. All species were found to occur repeatably, with the exception of peptide 1653 Da. This study has demonstrated that the majority of low molecular weight species in tears are repeatably present and do not exhibit diurnal variation. Further study aims to characterize these species and to identify changes in tear profiles between subject groups. [source] Influence of phenolic acids on growth and inactivation of Oenococcus oeni and Lactobacillus hilgardiiJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2003F.M. Campos Abstract Aims: To determine the effect of several wine-associated, phenolic acids on the growth and viability of strains of Oenococcus oeni and Lactobacillus hilgardii. Methods and Results: Growth was monitored in ethanol-containing medium supplemented with varying concentrations of hydroxybenzoic acids (p -hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acids) and hydroxycinnamic acids (p -coumaric, caffeic and ferulic acids). Progressive inactivation was monitored in ethanol-containing phosphate buffer supplemented in a similar manner to the growth experiments. Hydroxycinnamic acids proved to be more inhibitory to the growth of O. oeni than hydroxybenzoic acids. On the other hand, some acids showed a beneficial effect on growth of Lact. hilgardii. p- Coumaric acid showed the strongest inhibitory effect on growth and survival of both bacteria. Conclusions: Most phenolic acids had a negative effect on growth of O. oeni, for Lact. hilgardii this effect was only noted for p- coumaric acid. Generally, O. oeni was more sensitive to phenolic acid inactivation than Lact. hilgardii. Significance and Impact of the Study: Eight wine-derived, phenolic acids were compared for their effects on wine lactic acid bacteria. Results indicate that phenolic acids have the capacity to influence growth and survival parameters. The differences found between phenolic compounds could be related to their different chemical structures. [source] Synergistic antioxidative activities of hydroxycinnamoyl-peptidesJOURNAL OF PEPTIDE SCIENCE, Issue 10 2009Seon-Yeong Kwak Abstract Antioxidants have become an important subject of study as an active ingredient for cosmetics and preservatives for food. We synthesized antioxidative peptide conjugates of hydroxycinnamic acids (HCAs) such as ferulic acid (FA), caffeic acid (CA), and sinapic acid (SA) by SPPS method. We measured their potential antioxidant properties by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging test and lipid autoxidation inhibition test. When the antioxidative peptides, such as glutathione analogue (GS(Bzl)H) and carnosine (CAR), were conjugated to HCAs, their antioxidative activities were enhanced significantly. CA-peptides exhibited the highest free radical scavenging activity by the DPPH test, and showed good antioxidative activity in the lipid autoxidation test. FA- and SA-peptides showed excellent antioxidative activity in the lipid autoxidation test. Furthermore, we demonstrated a synergistic antioxidative activity of HCA-peptide conjugates by comparing their antioxidative activity with that of a simple mixture of HCAs and the antioxidant peptides. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Enhanced coloration reveals high antioxidant potential in new sweetpotato cultivarsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2003Martin Philpott Abstract Sweetpotato is one of the world's most important food crops, particularly in developing countries. The storage roots have high carbohydrate and vitamin A contents and possess strong antioxidant potential, previously attributed to their hydroxycinnamic acid content. We report on several new purple sweetpotatoes developed for their high anthocyanin content. Although the antioxidant activity of purple sweetpotato extracts was greater than that of sweetpotato lacking anthocyanins, anthocyanins alone could not account for all the activity. Extract components were separated by 2D paper chromatography, and their relative contributions to antioxidant activity were determined. The antioxidant activity of the extracts from sweetpotato was shown to be due to both anthocyanins and hydroxycinnamic acids, additively. Neither the anthocyanin content nor the antioxidant activity of sweetpotato flesh was affected by common cooking methods. These findings may be important in the light of the health-protective properties attributed to both antioxidants and anthocyanins. Copyright © 2003 Society of Chemical Industry [source] Lipids and antioxidants in groats and hulls of Swedish oats (Avena sativa L)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2002Susanne Bryngelsson Abstract Concentrations and compositions of total lipids (TL), fatty acids, tocopherols and tocotrienols, avenanthramides and free hydroxycinnamic acids were determined in groats and hulls from single samples of seven Swedish oat cultivars. Total antioxidant capacity (TAC) was measured using the radical 1,1-diphenyl-2-picrylhydrazyl as substrate. Results were evaluated by principal component analysis. Consistent differences in value of the variables analysed in groats and hulls were found, groats having higher concentrations of all compounds analysed except free cinnamic acids. Concentrations of E-vitamers (especially tocotrienols) were high in both groat and hull samples with high TL. Avenanthramides were high in hull samples with high TL, but this was not found in groats. Free cinnamic acids did not follow TL in either groats or hulls. TAC was generally higher in groats than in hulls. The within-group variation in TAC was less pronounced than that in chemical composition, especially in groats. The results did not suggest any strong relationship between TAC and individual antioxidants. © 2002 Society of Chemical Industry [source] Phenolic compounds, lycopene and antioxidant activity in commercial varieties of tomato (Lycopersicum esculentum)JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2002Isabel Martínez-Valverde Abstract Nine commercial varieties of tomato (Rambo, Senior, Ramillete, Liso, Pera, Canario, Durina, Daniella and Remate) produced in Spain were analysed for their lycopene content, content of phenolic compounds and antioxidant capacity. The phenolic compounds were characterised as flavonoids (quercetin, kaempferol and naringenin) and hydroxycinnamic acids (caffeic, chlorogenic, ferulic and p -coumaric acids). Antioxidant activity was measured using the DPPH and ABTS assays. The concentrations of lycopene and the various phenolic compounds as well as the antioxidant activity were significantly influenced by the tomato variety. Quercetin, the most abundant flavonoid, was found in concentrations ranging between 7.19 and 43.59,mg,kg,1 fresh weight, while naringenin levels were lower than 12.55,mg,kg,1. The most abundant hydroxycinnamic acid was chlorogenic acid, with values ranging from 14 to 32,mg,kg,1 fresh weight, followed by caffeic acid, while p -coumaric and ferulic acids showed similar concentrations lower than 5,mg,kg,1. The highest content of lycopene was found in Ramillete, Pera and Durina (>50,mg,kg,1 fresh weight), while the concentration in the other varieties was between 50 and 30,mg,kg,1, with the exception of Liso (less than 20,mg,kg,1). The antioxidant activity of tomato extracts varied with the tomato variety and the assay method used. Individual compounds found to be significantly related to antioxidant capacity were lycopene and ferulic and caffeic acids, but not quercetin and chlorogenic acid. © 2002 Society of Chemical Industry [source] Abscisic acid is involved in the response of grape (Vitis vinifera L.) cv. Malbec leaf tissues to ultraviolet-B radiation by enhancing ultraviolet-absorbing compounds, antioxidant enzymes and membrane sterolsPLANT CELL & ENVIRONMENT, Issue 1 2010FEDERICO J. BERLI ABSTRACT We investigated the interactions of abscisic acid (ABA) in the responses of grape leaf tissues to contrasting ultraviolet (UV)-B treatments. One-year-old field-grown plants of Vitis vinifera L. were exposed to photosynthetically active radiation (PAR) where solar UV-B was eliminated by using polyester filters, or where PAR was supplemented with UV-B irradiation. Treatments combinations included weekly foliar sprays of ABA or a water control. The levels of UV-B absorbing flavonols, quercetin and kaempferol were significantly decreased by filtering out UV-B, while applied ABA increased their content. Concentration of two hydroxycinnamic acids, caffeic and ferulic acids, were also increased by ABA, but not affected by plus UV-B (+UV-B) treatments. Levels of carotenoids and activities of the antioxidant enzymes, catalase, ascorbate peroxidase and peroxidase were elevated by +ABA treatments, but only if +UV-B was given. Cell membrane , -sitosterol was enhanced by ABA independently of +UV-B. Changes in photoprotective compounds, antioxidant enzymatic activities and sterols were correlated with lessened membrane harm by UV-B, as assessed by ion leakage. Oxidative damage expressed as malondialdehyde content was increased under +UV-B treatments. Our results suggest that the defence system of grape leaf tissues against UV-B is activated by UV-B irradiation with ABA acting downstream in the signalling pathway. [source] Polyamine metabolism in barley reacting hypersensitively to the powdery mildew fungus Blumeria graminis f. sp. hordeiPLANT CELL & ENVIRONMENT, Issue 3 2002T. Cowley Abstract Polyamine levels and activities of enzymes of polyamine biosynthesis and catabolism were examined in the barley cultivar Delibes (Ml1al + Ml(Ab)) reacting hypersensitively to the powdery mildew fungus, Blumeria graminis f. sp. hordei (race CC220). Levels of free putrescine and spermine and of conjugated forms of putrescine, spermidine and spermine were greatly increased 1,4 d following inoculation of barley with the powdery mildew. These changes in polyamine levels were accompanied by elevated activities of the polyamine biosynthetic enzymes ornithine decarboxylase (ODC), arginine decarboxylase (ADC) and S -adenosylmethionine decarboxylase (AdoMetDC) and the polyamine catabolic enzymes diamine oxidase (DAO) and polyamine oxidase (PAO). Activities of two enzymes involved in conjugating polyamines to hydroxycinnamic acids, putrescine hydroxycinnamoyl transferase (PHT) and tyramine feruloyl-CoA transferase (TFT) were also examined and were found to increase significantly 1,4 d after inoculation. The possibility that the increased levels of free spermine, increased polyamine conjugates, and increased DAO and PAO activities are involved in development of the hypersensitive response of Delibes to powdery mildew infection is discussed. [source] Multi-site genetic modulation of monolignol biosynthesis suggests new routes for formation of syringyl lignin and wall-bound ferulic acid in alfalfa (Medicago sativa L.)THE PLANT JOURNAL, Issue 1 2006Fang Chen Summary Genes encoding seven enzymes of the monolignol pathway were independently downregulated in alfalfa (Medicago sativa) using antisense and/or RNA interference. In each case, total flux into lignin was reduced, with the largest effects arising from the downregulation of earlier enzymes in the pathway. The downregulation of l -phenylalanine ammonia-lyase, 4-coumarate 3-hydroxylase, hydroxycinnamoyl CoA quinate/shikimate hydroxycinnamoyl transferase, ferulate 5-hydroxylase or caffeic acid 3- O -methyltransferase resulted in compositional changes in lignin and wall-bound hydroxycinnamic acids consistent with the current models of the monolignol pathway. However, downregulating caffeoyl CoA 3- O -methyltransferase neither reduced syringyl (S) lignin units nor wall-bound ferulate, inconsistent with a role for this enzyme in 3- O -methylation ofS monolignol precursors and hydroxycinnamic acids. Paradoxically, lignin composition differed in plants downregulated in either cinnamate 4-hydroxylase or phenylalanine ammonia-lyase. No changes in the levels of acylated flavonoids were observed in the various transgenic lines. The current model for monolignol and ferulate biosynthesis appears to be an over-simplification, at least in alfalfa, and additional enzymes may be needed for the 3- O -methylation reactions of S lignin and ferulate biosynthesis. [source] Enzyme activity of the phenylpropanoid pathway as a response to apple scab infectionANNALS OF APPLIED BIOLOGY, Issue 3 2010A. Slatnar The study was performed on apple trees, ,Golden Delicious' cv., which is a scab-susceptible cultivar. The phenolic content of apple fruit was determined in different parts of the peel. The phenolic compounds were analysed in the scab spot, in the tissue around the spot and in the healthy tissue. We determined the concentration of various phenolic compounds and related enzyme activities. Infection with the Venturia inaequalis fungus enhanced the metabolism of phenolic compounds at the scab spot, around the spot and in healthy peel. Compared with the healthy tissue and the tissue around the spot, the scab spot showed higher enzyme activity for all tested enzymes, except for dihydrochalcone 2,- O -glucosyltransferase, which had lower activity in the scab spot. In comparison to the healthy peel, the scab spot showed up to 3.4 times more hydroxycinnamic acids, up to 1.1 times more dihydrochalcones and up to 1.4 times more flavan-3-ols. In contrast, the healthy peel showed up to 1.6 times more flavonols than the scab spot. [source] Conjugated polyamines and hydroxycinnamic acids in grape berries during Botrytis cinerea disease development: differences between ,noble rot' and ,grey mould'AUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2003L. GENY Abstract Data are provided on contrasting levels of different categories of polyamines and hydroxycinnamic acids during the course of disease development due to Botrytis cinerea on ripe grape berries that led to either noble rot or to grey mould. Noble rot development was mainly characterised by a greater accumulation of wall-bound polyamines at the beginning of infection, whereas the disease process that led to grey mould was marked by an increase of conjugated polyamines. During grey mould infection, coumaric acid was the predominant hydroxycinnamic acid present in both healthy and infected grape berries regardless of infection stage, whereas ferulic acid was present at lower concentrations than the other hydroxycinnamic acids identified. Moreover, changes in the relative proportions of each of the three hydroxycinnamic acids considered showed contrasting patterns according to the sort of rot which developed. The different roles of these compounds (hydroxycinnamic acids and polyamines) and their involvement in the interaction between Botrytis cinerea and grapevines is discussed. During development of grey mould, coumaric acid was the predominant hydroxycinnamic acid at the beginning and the end of infection, whereas caffeic acid predominated during mid stage. [source] Hydroxycinnamic Acids as DNA-Cleaving Agents in the Presence of CuII Ions: Mechanism, Structure,Activity Relationship, and Biological ImplicationsCHEMISTRY - A EUROPEAN JOURNAL, Issue 46 2009Gui-Juan Fan Abstract The effectiveness of hydroxycinnamic acids (HCAs), that is, caffeic acid (CaA), chlorogenic acid (ChA), sinapic acid (SA), ferulic acid (FA), 3-hydroxycinnamic acid (3-HCA), and 4-hydroxycinnamic acid (4-HCA), as pBR322 plasmid DNA-cleaving agents in the presence of CuII ions was investigated. Compounds bearing o -hydroxy or 3,5-dimethoxy groups on phenolic rings (CaA, SA, and ChA) were remarkably more effective at causing DNA damage than the compounds bearing no such groups; furthermore, CaA was the most active among the HCAs examined. The involvement of reactive oxygen species (ROS) and CuI ions in the DNA damage was affirmed by the inhibition of the DNA breakage by using specific scavengers of ROS and a CuI chelator. The interaction between CaA and CuII ions and the influence of ethylenediaminetetraacetic acid (EDTA), the solvent, and pH value on the interaction were also studied to help elucidate the detailed prooxidant mechanism by using UV/Vis spectroscopic analysis. On the basis of these observations, it is proposed that it is the CaA phenolate anion, instead of the parent molecule, that chelates with the CuII ion as a bidentate ligand, hence facilitating the intramolecular electron transfer to form the corresponding CaA semiquinone radical intermediate. The latter undergoes a second electron transfer with oxygen to form the corresponding o -quinone and a superoxide, which play a pivotal role in the DNA damage. The intermediacy of the semiquinone radical was supported by isolation of its dimer from the CuII -mediated oxidation products. Intriguingly, CaA was also the most cytotoxic compound among the HCAs toward human promyelocytic leukemia (HL-60) cell proliferation. Addition of exogenous CuII ions resulted in an effect dichotomy on cell viability depending on the concentration of CaA; that is, low concentrations of CaA enhanced the cell viability and, conversely, high concentrations of CaA almost completely inhibited the cell proliferation. On the other hand, when superoxide dismutase was added before, the two stimulation effects of exogenous CuII ions were significantly ameliorated, thus clearly indicating that the oxidative-stress level regulates cell proliferation and death. These findings provide direct evidence for the antioxidant/prooxidant mechanism of cancer chemoprevention. [source] | |||||||||||||