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Oranges, grapefruits and lemons contained p-coumaric acid, caffeic acid, ferulic acid, and sinapic acid in bound form in concentrations of 10-100 mg/kg, whereby p-coumaric acid is localized chiefly in the peel. Hydroxybenzoic acids, chiefly salicylic acid and gentisic acid, and hydroxycoumarins were only found in traces.
The present study was performed to clarify the possible causes of the antimicrobial activity of honey. A sugar solution resembling honey in its high sugar content was made. The antimicrobial activities of both honey and this solution towards 21 types of bacteria and two types of fungi were examined. The results achieved by both were compared. The difference between them indicated the presence of antimicrobial substance(s) in honey. The kinds of antimicrobial substances (inhibines) in honey are discussed. Hydrogen peroxide is not the only inhibine in honey. In fact, inhibines in honey include many other substances. Two important classes of these inhibines are the flavonoids and the phenolic acids. Flavonoids have often been extracted from honey previously. In this study two phenolic acids (caffeic acid and ferulic acid) were extracted from honey for the first time.
Trials over two years were conducted using 1389 sweetpotato (Ipomoea batatas L.) genotypes collected from all over the world to characterize the polyphenolic composition in sweetpotato leaves. Wide variation was observed in relation to their total and individual leaf polyphenolic constituents. In all genotypes studied, the total polyphenol contents of sweetpotato leaf ranged from 1.42 to 17.1 g/100 g dry weight. The six different polyphenolic compounds were identified and quantified by NMR, FABMS, and RPHPLC analysis procedures. This is the first report of polyphenolic compositions in sweetpotato leaves. The relative levels of polyphenolic acids in sweetpotato leaves were as follows: 3,5-di-O-caffeoylquinic acid > 4,5-di-O-caffeoylquinic acid > chlorogenic acid (3-O-caffeoylquinic acid) > 3,4-di-O-caffeoylquinic acid > 3,4,5-tri-O-caffeoylquinic acid > caffeic acid. The highest 3,4,5-tri-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid occurred at 221 and 1183.30 mg/100 g dry weight, respectively.
An on-line HPLC-DPPH screening method for phenolic antioxidants in apple methanol/water (80:20, v/v) extracts was applied. The determination of antioxidants was based on a decrease in absorbance at 515 nm after postcolumn reaction of HPLC-separated antioxidants with the 2,2'-diphenyl-1-picrylhydrazyl radicals (DPPH*). Each of the antioxidants separated by the HPLC column was observed as a negative peak corresponding to its antioxidative activity. The on-line method was applied for quantitative analysis of the antioxidants. A linear dependence of negative peak area on concentration of the reference antioxidants was observed. For validation of the on-line method the limit of detection, LOD (microg/mL), and the limit of quantification, LOQ (microg/mL), of the phenolic compounds were determined. Comparison of the UV and DPPH radical quenching chromatograms with authentic compounds identified catechin, chlorogenic acid, caffeic acid, epicatechin, and phloridzin in the apple cultivars (Lobo, Golden Delicious, and Boskoop), and the distribution of total antioxidant activity was calculated.
OBJECTIVE: To study the chemical constituents in the aerial part of Thalictrum atriplex. METHOD: Chromatography and spectral analysis were used to isolate and elucidate the constituents. RESULT: Six compounds were isolated from the aerial part of Thalictrum atriplex, and elucidated as protocatechuic acid, caffeic acid, p-coumaric acid, kaempferol, beta-sitosterol and N-methylcorydaldine. CONCLUSION: They are all isolated from the plant for the first time.
Sinapic acid, isoferulic acid, caffeic acid and chrysin were isolated from the alcoholic extraction of propolis and identified by spectrometric methods. The first three compounds were shown with inhibitive effect of against Staphylococcus aureus, while chrysin was ineffective.
Several compounds characterised as protocatechuic acid, caffeic acid, syringin, rotundic acid and pedunculoside were isolated from the leaves of Ilex chinensis, a Chinese crude drug. A novel compound cyclohexanone pedunculosyl-3,23-O-acetal was identified and proposed as a pedunculoside derivative produced in the extracting procedure.
Fernblock, an aqueous extract of the aerial parts of the fern Polypodium leucotomos, used as raw material for topical and oral photoprotective formulations, was fractioned by HPLC and the main components with antioxidant capability were identified by means of UV spectra, electrochemical detection, and MSn. Phenolic compounds were identified as 3,4-dihydroxybenzoic acid, 4-hydroxybenzoic acid, vanillic acid, caffeic acid, 4-hydroxycinnamic acid, 4-hydroxycinnamoyl-quinic acid, ferulic acid, and five chlorogenic acid isomers. Total ferric antioxidant capacity (FRAP) of HPLC eluted fractions was measured. The results suggest that the herein identified compounds support, at least partially, the antioxidant and radical scavenging capacities of Fernblock.
A new lignan, actaealactone (1), and a new phenylpropanoid ester derivative, cimicifugic acid G (2), together with 15 known polyphenols, protocatechuic acid, protocatechualdehyde, p-coumaric acid, caffeic acid, methyl caffeate, ferulic acid, ferulate-1-methyl ester, isoferulic acid, 1-isoferuloyl-beta-d-glucopyranoside, fukinolic acid, and cimicifugic acids A, B, and D-F, were isolated from an extract of the rhizomes and roots of black cohosh (Actaea racemosa). The structures of the new compounds were determined on the basis of NMR spectroscopic analysis. Compounds 1 and 2 displayed antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay with IC(50) values of 26 and 37 microM, respectively. Other antioxidants identified from A. racemosa include cimicifugic acid A (3), cimicifugic acid B (4), and fukinolic acid (5). Compounds 1 and 2 also exhibited a small stimulating effect on the growth of MCF-7 breast cancer cell proliferation 1.24-fold (14 microM) and 1.14-fold (10 microM), respectively, compared to untreated cells.
In this study, a comparative assessment was undertaken of nutritional factors that are likely to influence in vivo growth of the S and P-types of necrotrophic root rot fungus Heterobasidion annosum and of the damping off pathogen Fusarium avenaceum respectively. The results indicate that glucose and fructose but not cellobiose or sucrose supported growth of these fungi when used as sole carbon source. Particularly for P-types and F. avenaceum, however, the utilization of cellobiose and sucrose was considerably enhanced by several fold in the presence of ethanol. In addition, key plant cell wall phenolics (ferulic acid, caffeic acid, p-coumaric acid) at 0.025% inhibited growth of the test fungi. But this toxicity was reversed in the presence of exogenously added cell wall sugars (glucose, fructose, sucrose, cellobiose) except for the P-types where sucrose addition was apparently slightly effective. Similarly, ethanol whether alone or in combination with the phenolics was poorly utilized except for F. avenaceum. The importance of these results in understanding factors influencing growth and development during pathogenesis of the necrotrophs on their conifer hosts is discussed.
The ability of 3 plant flavonoids (morin, myricetin and quercetin) and 4 polyphenolic acids (caffeic acid, chlorogenic acid, ellagic acid and ferulic acid) to inhibit the genotoxic effects of a number of cooked-food mutagens (IQ, MeIQ, MeIQx, Trp-P-1 and Trp-P-2), was investigated in a bacterial mutation assay using Salmonella typhimurium TA98 as indicator and hepatic S9 mixes from either SWR mice or Syrian hamsters as metabolic activating systems. Although the polyphenolic acids failed to have an effect, the flavonoids generally inhibited IQ, MeIQ, MeIQx and Trp-P-1 induced mutagenesis in a dose-dependent manner, irrespective of the source of S9. This was not the case with Trp-P-2 where the flavonoids were only observed to inhibit when SWR mouse S9 but not Syrian hamster S9 was used. Of the 3 compounds, myricetin and quercetin were superior to morin in their inhibitory capacity.
The antioxidant activity of aqueous infusions of sage emerges from specific components present in that herb. In an attempt to investigate the chemical nature and properties of these components, four organic solvent extracts from aqueous infusions of sage were examined. HPLC analyses of these extracts led to the separation of a number of components, of which four were identified and quantified through the use of standard compounds of known chromatographic HPLC profiles. These compounds are the diterpenes carnosic acid, carnosol, and rosmanol and the hydroxycinnamic acid caffeic acid. The antioxidant activity and polyphenol content were determined in the four organic solvent extracts and the left-over aqueous fraction. Both polyphenolic and nonpolyphenolic substances present in the extracts arise as significant contributors to the observed antioxidant activity of the derived extracts and thus sage itself. In this sense, they reflect the antioxidant potential of the aqueous infusions of sage toward reactive oxygen species generated through variable mechanisms of iron-promoted oxidative processes.
Lignins, tannins and flavonoids are commonly found polyphenols. Among these polyphenols, lignins, polymers of phenylpropenoids complexed with polysaccharides, were the least cytotoxic and most potently stimulated the production of nitric oxide (NO), citrulline and asparagine by mouse macrophage-like Raw 264.7 cells. The maximum production of these substances reached the level attained by lipopolysaccharide (LPS). However, epigallocatechin gallate, phenylpropenoid monomers (ferulic acid, caffeic acid) and gallic acid (component unit of tannin) were inactive. These data suggest that the macrophage-stimulation activity of polyphenols depends, at least in part, on their molecular weight or structural configuration. There was a positive relationship between the extent of asparagine production and that of NO or citrulline. Western blot analysis demonstrated that both lignins and LPS elevated the cellular level of asparagine synthetase. The present study suggests the possible link between the stimulated asparagine production and macrophage activation.
The interaction between coffee (100 mg freeze-dried home brew/kg body weight) and dietary constituents was assessed for anti-genotoxic effects against cyclophosphamide, N-methyl-N-nitro-N- nitrosoguanidine (MNNG), N-nitroso-N-ethylurea, mitomycin C and urethane (URE) in the mouse bone marrow micronucleus test. Combinations of dietary constituents consisting of (1) chlorogenic acid, caffeic acid, ellagic acid and ferulic acid, (2) beta-carotene, curcumin and alpha-tocopherol, (3) chlorogenic acid, curcumin, alpha-tocopherol, anethole and eugenol, and (4) beta-carotene, curcumin, ellagic acid and chlorogenic acid were used in this study. Before the genotoxin was injected i.p., identical groups of mice were orally administered either vehicle control, coffee, dietary constituents, or coffee plus dietary constituents. Co-administration of coffee with the dietary constituents enhanced the anti-genotoxic effect compared with that of either coffee or the dietary constituents alone. Two-factor analysis of variance of the data suggests that there is a significant synergistic interaction between coffee and the dietary constituents for anti-genotoxic effects against MNNG (combination 1 and 2) and URE (combination 4).
A high performance liquid chromatography (HPLC) method was developed for the simultaneous quantification of five major active ingredients (markers) in Ixeris sonchifolia (Bge.) Hance, namely chlorogenic acid, caffeic acid, luteolin-7-O-beta-D-glucuronide, luteolin-7-O-beta-D-glucoside and luteolin. Samples were extracted with 70% methanol. The chromatographic separation was performed on a Hypersil ODS(2) column (250 mm x 4.6 mm i.d.; 5 microm) with a gradient of acetonitrile and 0.5% (v/v) aqueous acetic acid, at a flow rate of 1.0 ml/min, detected at 335 nm. Five regression equations showed good linear relationships (r(2)>0.999) between the peak area of each marker and concentration. The assay was reproducible with overall intra- and inter-day variation of less than 3.2%. The recoveries, measured at three concentration levels, varied from 94.1% to 100.7%. This assay was successfully applied to the determination of the 5 bioactive compounds in 18 samples. The results indicated that the developed assay method was rapid, accurate, reliable and could be readily utilized as a quality control method for I. sonchifolia (Bge.) Hance.
Co-oxidation of chlorogenic acid, caffeic acid, aesculetin and lucigenin with linoleic acid and egg phosphatidyl choline leads to the formation of fluorescent polymer materials. The fluorescent products are more lipophylic, they have lower elution volumes on Sephadex LH-20 column than related phenols and they differ by their fluorescence and chromatographic properties considerably from polymer lipid peroxidation products. From the presence in the excitation fluorescence spectra of a band corresponding to the phenols it was concluded that the fluorophoric groups were similar in both cases. The data are discussed in terms of liquid phase peroxidation and the appearance of the fluorescent species are attributed to the production of molecular adducts as a result of lipid and phenoxyl radical recombination. The characteristics of products obtained are compared with properties of fluorescent "plant ageing" pigments accumulated in aged and damaged plant cells.
This research studies in detail the contents of phenolic compounds determined by the Folin-Ciocalteu reagent and the antioxidant activities determined by the TEAC (Trolox equivalent antioxidant capacity), DPPH (using diphenyl-p-picrylhydrazyl radical), and FRAP (ferric reducing antioxidant power) methods, and their correlations for used standards with these methods (catechine, gallic acid, caffeic acid, ferulic acid, Trolox, ascorbic acid, and ferrous sulfate) and extracts from several species of commonly consumed vegetables were studied in detail. The comparison of absolute values of absorption coefficients for used standards and for individual methods allows one to choose optimal common standards for methods to be compared. The procedures applied for the same sets of the extracts using identical calibration procedures and common standards allowed better comparison of the results obtained by the TEAC, DPPH, and FRAP methods. The values of content of phenolic substances and total antioxidant activity of the sets of samples correlate very well for all used methods. The very high values of antioxidant activity were found in intensely colored vegetables (red cabbage, red onion, etc.), and the values were very low in watery vegetables such as potato, marrow, and cucumber.
We have shown, in a preliminary report, that macrophages can induce strand breaks in the DNA of co-cultured tumor cells (Chong et al., 1988). The present study is designed to determine if oxygen-centered species generated by the cell-free enzyme-substrate combination of hypoxanthine and xanthine oxidase can induce similar lesions and to identify the specific mediator(s). We report that co-incubation of murine mammary tumor cell lines with hypoxanthine and xanthine oxidase leads to the induction of DNA-strand breaks as determined by fluorescence analysis of DNA unwinding (FADU) assay or alkaline elution techniques. This damage is preventable by catalase which removes hydrogen peroxide but no protection is provided by agents to remove or prevent the formation of superoxide anion (superoxide dismutase), or hydroxyl radical (mannitol or the iron chelator o-phenanthroline). Likewise, cyclooxygenase or lipoxygenase inhibitors of arachidonate metabolism (indomethacin, nordihydroguaiaretic acid, caffeic acid) or bromophenacyl bromide do not alter the degree of DNA scission. Treatment with higher doses of oxygen species leads to significant toxicity as determined by evaluation of cell growth potential or colony-forming ability. Again, toxicity is prevented only by the presence of catalase. Tumor cells are able to rejoin strand breaks at lower, less toxic doses. When comparing different tumor cell subpopulations at various stages of progression, i.e., metastatic vs. nonmetastatic, for sensitivity to hydrogen peroxide-induced strand breakage, we found that at lower concentrations (less than 5 microM) metastatic populations are sensitive whereas nonmetastatic populations exhibit no significant breakage. At higher concentrations of hydrogen peroxide, all lines were sensitive, suggesting that a lower threshold of sensitivity may exist for more progressed tumor cell lines.