Differences In Phenolic Content Research Articles

Obtaining of the antioxidants by supercritical fluid extraction

One of the important trends in the food industry today is demand for natural antioxidants from plant material. Synthetic antioxidants such as butylated hydroxytoluene (BHT), and butylated hydroxyanisole (BHA) are now being replaced by the natural antioxidants because of theirs possible toxicity and as they may act as promoters of carcinogens. The natural antioxidants may show equivalent or higher antioxidant activity than the endogenous or the synthetic antioxidants. Thus, great effort is being devoted to the search for alternative and cheap sources of natural antioxidants, as well as to the development of efficient and selective extraction techniques. The supercritical fluid extraction (SFE) with carbon dioxide is considered to be the most suitable method for producing natural antioxidants for the use in food industry. The supercritical extract does not contain residual organic solvents as in conventional extraction processes, which makes these products suitable for use in food, cosmetic and pharmaceutical industry. The recovery of antioxidants from plant sources involves many problematic aspects: choice of an adequate source (in terms of availability, cost, difference in phenolic content with variety and season); selection of the optimal recovery procedure (in terms of yield, simplicity, industrial application, cost); chemical analysis of extracts (for optimization purposes a fast colorimetric method is more preferable than a chromatographic one); evaluation of the antioxidant power (preferably by the different assay methods). The paper presents information about different operational methods for SFE of bioactive compounds from natural sources. It also includes the various reports on the antioxidant activity of the supercritical extracts from Lamiaceae herbs, in comparison with the activity of the synthetic antioxidants and the extracts from Lamiaceae herbs obtained by the conventional methods.

Effects of genotype, location and baking on the phenolic content and some antioxidant properties of cereal species

SummaryIn order to assess the effect of genotype, location and their interaction on total phenolic content (TPC) of chemical extracts, the whole grains of durum and soft wheat, oat, barley and triticale were evaluated. Data showed differences in phenolic content of chemical extracts among cereal species and the analysis of variance confirmed the key role of location. Besides TPC and trolox equivalent antioxidant capacity (TEAC) values assessed by chemical extraction were compared with those obtained with an in vitro digestive enzymatic extraction. Differences were found between methanolic and enzymatic extracts, and data confirmed that enzymatic technique enhanced extraction of antioxidants but pointed out lesser differences among cereal types. The breads obtained by flours enriched with different levels of bran were also evaluated. Chemical extracts highlighted the increasing levels of antioxidants according to bran enrichments, without pointing out changes caused by baking. The enzymatic extraction instead did not show differences regarding to bran enrichments, but documented a loss in antioxidant properties of breads in respect to corresponding flours. On the other hand the scarce differences between flours and corresponding breads did not allow asserting that baking modified the TPC and TEAC, independently of the extraction methods used. Indeed, during baking process, also the observed phenolic acids profile variations did not vary the antioxidant properties of breads.

Lactic acid fermentation of two sorghum varieties is not affected by their polyphenol contents

The study was conducted to investigate sorghum grain variety differences in lactic acid fermentation based on their differences in phenolic contents. The study wa s conductedas a 2 x 5 x 4 factorial design with three factors: Factor 1: Sorghum variety (white and red sorghum); Factor 2: Control treatment without lactic acid bacteria (LAB) and LAB treatments (Pediococcus acidilactici CNCM MA 18/5 M or Lactobacillus plantarum Medipharm or Lactobacillus plantarum NCIMB 41229 or Lactobacillus farciminis CNCM MA 67/4 R (LF1); Factor 3: Incubation time (0, 4, 8, and 24 hours). Sorghum samples (50 g of red or white sorghum) were mixed with sterile distilled water at a ratio of 1g: 1.4g of water and inoculated with 0.05 ml of an overnight culture of LAB at the Food and Nutrition Laboratory, University of Plymouth, U.K. The range of phenolic contents of red and white sorghum was 5.53 ± 0.48 and 4.05 ± 0.80g/100g grain respectively. Results suggest fermentation was not affected by the phenolic content of sorghum as there were no significant differences in lactic acid production between sorghum varieties. Fermentation of both varieties of sorghum with LAB produced a low pH medium (pH≤3.65) that had a high lactic acid concentration (≥203.67 mmol/L). Both grain varieties may be successfully fermented for inclusion in moist feed for poultry despite differences in phenolic contents.

Tyrosinase immobilized reactor as a fast tool for polyphenolic index of tea

A new approach for the determination of polyphenolic index of black and green teas has been developed employing a bioreactor with mushroom tyrosinase immobilized on aminopropyl-controlled pore glass (AMP-CPG). Initially a linear correlation ( r 2 = 0.997) of catechin content between the Folin-Ciocalteu (FC) and the enzymatic assays is obtained. Our method appears to be more specific and rapid. Successively the inhibition of the enzymatic oxidation of catechin by some tea components like gallic acid (GA), epigallocatechin (EGC), epigallocatechingallate (EGCG) and epicatechin (EC) is investigated. Finally when tea samples are analyzed by using the new method it appears that green tea is the strongest inhibitor followed by black tea and flavored tea. The level of polyphenols, which is correlated to the extent of inhibition, is reported as epigallocatechin equivalents and the results are compared with those obtained using the FC assay and the vanillin index. The differences in phenol content found by applying the three methods are discussed in terms of the different specificities of the analytical basis.

Varietal differences in phenolic content and astringency in skin and flesh of hardy kiwifruit resources in Japan

Varietal differences in the total phenolic content and astringency in the skin and flesh were determined among the cultivars and local collections of hardy kiwifruit with a ploidy variance found in Japan. The average values of the total phenolic content in the skin and flesh were 2.66 and 0.18 g 100 g −1 FW, respectively. There were large varietal differences in the total phenolic content in the skin in the range of 1.3–5.0 g 100 g −1 FW. Kochi (tetraploid), while Gassan and ‘Mitsuko’ (hexaploid) contained a larger amount of total phenolics. High astringency was found in Gassan, ‘Mitsuko’ and ‘Hoko’ (hexaploids) and Kochi. HPLC analysis showed that the major components of phenolics in the flesh were (+)-catechin, chlorogenic acid, rutin, (−)-epicatechin and quercetin.

Comparative study of phenolic compounds in different Brazilian rice ( Oryza sativa L.) genotypes

This study was conducted to evaluate the natural variability of total, extractable and non-extractable phenolics in pigmented and non-pigmented rice genotypes ( Oryza sativa L.) and to estimate whether the contents and distribution of these compounds are typical for genotypes from indica and japonica subspecies. Twenty-one samples of commercial as well as new genotypes of brown rice, including seven pigmented genotypes were obtained from two Agronomic Institutes in South Brazil. Free and conjugated phenolics were extracted with ethanol, while bound phenolics were released by alkaline hydrolysis. Total phenolics were estimated in both fractions by the Folin–Ciocalteau method. Genotypes from japonica and indica non-pigmented subspecies were not statistically distinguishable from each other, but differences in phenolic contents were associated with pericarp color. Despite individual differences, total phenolics were four times higher in pigmented than in non-pigmented genotypes (4246 and 1073 mg ferulic acid equiv. kg −1, respectively). These high amounts were mostly due to the presence of extractable (free and conjugated) phenolics, which comprised up to 81% of total phenolics for pigmented genotypes. Non-extractable (bound) phenolics comprised 40% of total phenolics of non-pigmented rice genotypes while pigmented genotypes presented greater absolute amounts, but their contribution on total phenolics was small.

Altitudinal Variation of Phenolic Contents in Flowering Heads of Arnica montana cv. ARBO: a 3-Year Comparison

In continuation of our studies of altitudinal effects on secondary metabolite profile of flowering heads from taxa of the Asteraceae, we investigated phenolic contents and radical scavenging potential from cultivated plants of Arnica montana cv. ARBO during the growing seasons 2003, 2004, and 2005. By conducting experiments on potted plants, we excluded that differences in phenolic contents from plants grown at different altitudes were related primarily to differences in soil composition at these sites. To assess altitudinal and interseasonal variation, plants of A. montana cultivar ARBO were grown in nine experimental plots at altitudes between 590 and 2,230 m at Mount Patscherkofel near Innsbruck, Austria. In all growing seasons and regardless of the soil the plants were grown in, the proportion of flavonoids with vicinal-free hydroxy groups in ring B to flavonoids lacking this feature, and the total amount of caffeic acid derivatives, significantly increased with elevation. These increases of antioxidant phenolics corresponded to an increase of the radical scavenging potential of extracts from plants grown at different altitudes. The results are discussed in regard to previous studies that suggest that enhanced UV-B radiation and decreased temperatures trigger augmented biosynthesis of UV-absorbing and antioxidant phenolics in higher plants.

Differences in phenolic content and antioxidant activity in yellow and purple-fleshed potatoes grown in the Czech Republic

The aim of this study was to determine the total phenolic (TP) content and antioxidant activity (AA) in yellow (cvs. Impala, Karin, Dita, Saturna) and purple-fleshed (cvs. Valfi, Violette) potatoes grown in the Czech Republic in 2004 in four locations in precise field trials. TP content was determined by Folin-Ciocalteau assay and AA by DPPH assay both in freeze-dried tuber matter. Results showed a statistical significant difference in TP content and AA between yellow and purple-fleshed potatoes. Purple-fleshed cultivars showed higher TP content (by 60%) than yellow-fleshed cultivars; AA in purple-fleshed cultivars was twice as high as in yellow-fleshed potatoes. A medium linear correlation between TP and AA was found ( <I>r</I><sup>2</sup> = 0.747). Average TP content in yellow-fleshed cultivars was 2.96 GAE (g of gallic acid per kg dm); in purple-fleshed cultivars it was 4.68 GAE. Average AA in yellow-fleshed cultivars was 11.26 EAA (mg of ascorbic acid per 100 g dm) and in purple-fleshed cv. 24.79 EAA. Purple-fleshed potatoes showed a lower variation among localities (only 6%). Hence, regarding a relatively high potato intake by Czechs (72 kg per capita a year), contribution of potatoes, especially purple-fleshed, to total antioxidants intake should be considered.

The differences in phenolic content in rivers exposed and non-exposed to anthropogenic contamination

The purpose of the work was to determine the differences in a kind, number and concentrations of phenol, chlorophenols, chlorocatechols chlorinated methoxyphenols (chloroguaiacols, chlorosyringols) and 3,4,5-trichloroveratrole in the drainage of the Dzierżązna river, the flow non-exposed to anthropogenic contamination and in the Ner river, the flow exposed to anthropogenic pollution. The samples of water were collected in the Dzierżązna river in the Swoboda locality, the inflow of the Dzierżązna river – the Ciosenka river and, also, in the spring situated in Ciosny Sady locality. Water of the Ner river was collected in points near Łódź, Konstantynów, Poddębice and Dąbie towns. The compounds were condensed (adsorbed) and eluted with methylene chloride on octadecyl C18 layer in a Baker Separex system. The obtained eluent was separated using the method of gas chromatography and analysed using mass spectrometry technique. In samples collected from the drainage of the Dzierżązna river phenol, chlorophenols, guaiacol, trichloroguaiacol, tetrachloroguaiacol, trichlorosyringol and 3,4,5-trichloroveratole were determined. As no anthropogenic sources are situated within the drainage of the Dzierżązna river, we may suppose that most of the determined compounds are mainly of natural origin. No or trace concentrations of chlorinated methoxyphenols were noted in the water of the Ner river, but a higher number, and concentrations of chlorophenols and additionally chlorocatechols were determined in this flow. It is also apparent that changes in a number and concentrations of phenols in the water of the Ner river did not prove a seasonal character, which was typical of the Dzierżązna drainage waters.

Comparison of the antioxidant activity of two Spanish onion varieties

Phenol content and antioxidant activity of two Spanish onion varieties, namely white onion and Calçot de Valls, have been studied. White onions contained higher phenol content than Calçot onions, with values which ranged from 2.57 ± 0.51 to 6.53 ± 0.16 mg gallic acid equivalents/g dry weight (GAE/g DW) and 0.51 ± 0.22 to 2.58 ± 0.16 mg GAE/g DW, respectively, depending on the solvent used. Higher phenol content was associated with higher antioxidant capacity. White onion extracts had the highest antioxidant activity at 86.6 ± 2.97 and 29.9 ± 2.49 μmol Trolox/g DW for TEAC and FRAP assays, respectively, while the values for the Calçot variety were 17.5 ± 0.46 and 16.1 ± 0.10 μmol Trolox/g DW. The antioxidant capacity of freeze dried powder from both onion varieties was also tested in sunflower oil-in-water emulsions, and hydroperoxide formation was monitored during storage at 40 °C. In accordance with differences in phenol content, Spanish white onions had better antioxidant activity, while Calçot was only effective in the early stages of the oxidation process.

Varietal Differences in Phenolic Content and Antioxidant and Antiproliferative Activities of Onions

Varietal Differences in Phenolic Content and Antioxidant and Antiproliferative Activities of Onions

Varietal Differences in Phenolic Content and Antioxidant and Antiproliferative Activities of Onions

Epidemiological studies have indicated that the consumption of fruits and vegetables is associated with a reduced risk for the development of chronic diseases, such as cardiovascular disease and cancer. Phytochemicals, including phenolics and flavonoids, are suggested to be the major bioactive compounds contributing to the health benefits of fruits and vegetables. Onions are a major source of dietary flavonoids; however, there may exist varietal differences in composition, concentration, and beneficial activities. To characterize these differences, shallots and 10 onion (Allium cepa L.) varieties commonly available in the United States (Western Yellow, Northern Red, New York Bold, Western White, Peruvian Sweet, Empire Sweet, Mexico, Texas 1015, Imperial Valley Sweet, and Vidalia) were evaluated for total phenolic and flavonoid contents and antioxidant and antiproliferative activities. Shallots contained the highest total phenolic content (114.7 +/- 10.0 mg/100 g of sample) among the varieties tested, with a 6-fold difference observed when compared to the variety with the lowest phenolic content (Vidalia, p < 0.05). Western Yellow onion variety exhibited the highest total flavonoid content (69.2 +/- 3.7 mg/100 g of onion) of the varieties tested, with an 11-fold difference when compared to the variety with the lowest flavonoid content (Western White, p < 0.05). Shallots exhibited the highest total antioxidant activity (45.5 +/- 2.1 micromol of vitamin C equiv/g of onion), followed by Western Yellow, New York Bold, Northern Red, Mexico, Empire Sweet, Western White, Peruvian Sweet, Texas 1015, Imperial Valley Sweet, and Vidalia. For all varieties, both total phenolic and flavonoid contents were strongly correlated with total antioxidant activity (R (2) = 0.9668, p < 0.05; and R (2) = 0.7033, p < 0.05, respectively). The proliferation of HepG(2) and Caco-2 cells was significantly inhibited in a dose-dependent fashion after exposure to the Western Yellow, shallots, New York Bold, and Northern Red extracts, with Western Yellow, shallots, and New York Bold exhibiting the highest antiproliferative activity against HepG(2) cells and New York Bold and Western Yellow exhibiting the highest antiproliferative activity against Caco-2 cells. However, the varieties of Western White, Peruvian Sweet, Empire Sweet, Mexico, Texas 1015, Imperial Valley Sweet, and Vidalia demonstrated weak antiproliferative activity against both HepG(2) and Caco-2 cells. These results may influence consumers toward purchasing onion varieties exhibiting greater potential health benefits and may significantly affect future breeding efforts to enhance onion nutritional qualities.

Fertilizer, Flower Bud Removal and Vegetative Pruning of Echinacea species (Purple Coneflower) Influence Biomass and Phenolic Content

Purple Coneflower [Echinacea sp. (Asteracea)] is of great value to the horticultural, pharmaceutical, and herbal industry. More research is needed to determine cultural practices that will produce a plant high in biomass and phenolic content, the chemical used for testing the quality of the harvested plant on a percent basis of roots, flowers and vegetative parts. The objective of this experiment is to determine if biomass and phenolic content of Echinacea purpurea and E. purpurea `Magnus' is influenced by fertilization after flower bud removal and vegetative pruning. The second objective of this study is to form an evaluation of the differences in biomass and phenolic content of five cultivars of E. purpurea and five species of Echinacea. Biomass and phenolic content will be evaluated to determine if exposing these plants to various treatments increases the quality of the plant over 1 and 2 years of growth. Differences in dry weights of Echinacea species and cultivars harvested after the first year of growth was determined. There was a significant difference in total dry weight between E. purpurea cultivars. Echinacea purpurea `Bright Star' and `Clio' significantly produced the most total dry weight compared to all other cultivars. There was no significant difference in root or flower biomass between cultivars. Biomass of Echinacea species was significantly different in root, vegetaive and flower parts. The total biomass of E. purpurea and E. tennesseensis was significantly higher compared to other species. Echinacea pallida and E. paradoxa were not significantly different from E. purpurea in root biomass, even though both species were small in above ground growth. Echinacea tennesseensis significantly produced 45% to 105% more flowers compared to other species. Differences in phenolic content between species and cultivars will also be presented.

255 Biomass and Phenolic Content of Echinacea Species Grown in Kentucky

Purple coneflower, Echinacea sp. (Asteraceae), is a herbaceous perennial native to North America. Within the past decade, extensive research has been conducted to confirm echinacea's immunostimulatory, antiviral, and antibacterial benefits to humans. E. angustifolia, E. purpurea, and E. pallida are the primary species grown and studied for the herbal industry. However, there are other species and cultivars that may produce higher yields in biomass and chemical quality. The objective for this study is to evaluate the differences in biomass and phenolic content of five cultivars of E. purpurea and five species of Echinacea under Kentucky growing conditions. Differences in biomass (dry weight) of Echinacea species and cultivars harvested after the first year of growth was determined. There was a significant difference in total dry weight between E. purpurea cultivars. E. purpurea `Bright Star' and `Clio' produced significantly greater total dry weight compared to all other cultivars. There was no significant difference in root or flower biomass between cultivars. Biomass production differed between Echinacea species for root, vegetative, and flower parts. The total biomass of E. purpurea and E. tennesseensis was significantly higher compared to other species. E. pallida and E. paradoxa were not significantly different from E. purpurea in root biomass, even though both species produced less above-ground growth. E. tennesseensis produced 45% to 105% more flowers compared to other species. Differences in phenolic content between species and cultivars will also be presented.

036 Antioxidant Capacity and Anthocyanin and Phenolic Content of Highbush Blueberries of Different Maturities

Highbush blueberry (Vaccinium corymbosum) fruit of the cultivars `Bergitta', `Bluegold', and `Nelson' were harvested at six stages of maturity and evaluated for their antioxidant capacity and anthocyanin and phenolic content. Fruit of the four earliest maturities were also stored at 20 °C for up to 8 days. At the time of harvest, fruit of different maturities had substantial differences in their anthocyanin content, and less marked differences in phenolic content and antioxidant capacity. Substantial anthocyanin synthesis occurred in under-ripe fruit during 20 °C storage, and varied depending on fruit maturity at harvest. Total phenolic content changed very little during storage, and there was no change in fruit antioxidant capacity. The results suggest that anthocyanin phenolics are formed on or off the plant, primarily from other pre-existing phenolic components. Whether phenolics are present as anthocyanins or other colorless forms, has relatively little impact on antioxidant capacity.

Chemical and morphological variation of Mediterranean woody evergreen species: Do plants respond to ungulate browsing?

Abstract. Plant defense theories suggest that chemical or structural defences should be maximized when and where browsing is most likely to occur. We tested this hypothesis on four evergreen woody species growing in a Mediterranean area with a high density of ungulates. In this system, levels of browsing are more intense in the winter (due to the lack of annual plants) and young foliage is often preferred. Therefore we predicted that the chemical defences of these species, namely their phenolic content, would vary with leaf age, season and damage intensity. In addition, we tested whether ungulates preferentially selected species containing lower phenolic levels, and also whether browsing induced either chemical or morphological changes in damaged plants. Phenolic levels varied greatly between plant species; ungulates browsed preferentially on the species with the lowest phenolic levels. No difference in phenolic content was found between browsed and unbrowsed trees. Morphological changes in heavily browsed trees included an increase in shoot and leaf density and a net decrease in leaf size. We suggest that for Mediterranean plants, which have evolved under high browsing pressure from large mammals, the production of small leaves and dense shoots in response to browsing might decrease ungulate foraging efficiency and hence reduce the rate of further damage as effectively as high levels of chemical defence.

Polyphenols as potential markers to differentiate juvenile and mature chestnut shoot cultures.

The phenolic contents of eight in-vitro-cultivated chestnut clones (Castanea sativa Mill. and C. sativa x C. crenata Siebold & Zucc. hybrids) were analyzed both qualitatively and quantitatively. The aim of the work was to identify potential phenolic markers of: (i) juvenile or mature state; (ii) topophysical origin; and (iii) rooting capacity. A condensed tannin was detected in mature material but not in juvenile material, indicating that it could be used as a qualitative marker. Other qualitative phenolic differences were found between basal shoots and crown shoots of some clones, but it was not possible to discriminate among these materials in a general way. Canonical discriminant analysis was used for the study of quantitative markers. Differentiation between mature and juvenile material, and between materials differing in in vitro rooting capacity was possible according to the results of the analysis. Nevertheless, no significant quantitative differences were found between the phenolic content of material of basal shoot origin and that of crown shoot origin, indicating that the greater juvenility of material of basal origin compared with that of crown origin was not reflected in differences in phenolic content.

モモ果実の渋味発生に及ぼす環状はく皮の影響

Lateral bearing branches of two peach cultivars, 'Sanyo-suimitsu' grafted on Prunus persica or P. tomentosa rootstocks and those of 'Shimizu-hakuto' grafted on P. persica root- stock, were girdled at Stages 1 and 2 of fruit development. At harvest phenolic contents were determined and related to astringency. The relationships between phenolic content and fruit maturity and pit-splitting of fruit, were also investigated. Girdling advanced fruit maturation and increased fruit weight, except in 'Sanyo-suimitsu' grafted on P. tomentosa. Total soluble solids contents were higher in fruits from girdled branches ex- cept for 'Shimizu-hakuto'. Regardless of cultivar and rootstock, the total phenolic contents and fraction of higher molecular weight phenols were higher in fruits from girdled branches than in fruits from non-girdled branches. However, there was no consistent correlation between the girdling stage and phenolic content in the fruits. The earlier the fruit matured, the higher was the phenolic content, especially those on girdled branches. The exception were those fruits from non-girdled branches of 'Sanyo-suimitsu' trees grafted on P. tomentosa rootstock. There were little differences in phenolic contents between fruit with and without split pits, although girdling markedly increased the frequency of split pits.

Polyphenol Variation in Sitka Spruce

The distribution of polyphenols in various tissues of Sitka spruce is described, with data on seasonal variation. Leaves were rich in a variety of flavonoids, but the main stem constituents were stilbenes. There was great variation both between and within provenances in most components, but evidence was obtained for differences in stilbene content attributable to provenance. Different temperature regimes caused marked differences in phenolic content, but clonal characteristics generally overrode treatment differences. High temperature favored polymeric polyphenol synthesis, while a lower temperature promoted high phenolic accumulations especially of monomeric components.

The Use of Tissue Culture in the Study of Single Gene Resistance of Tomato to Phytophthora infestans1

Abstract Tissue culture lines were established from tomato varieties susceptible and resistant to tomato race 0 of Phytophthora infestans. Inoculation of tissue culture pieces showed that at least partial resistance to the pathogen was maintained in the undiferentiated callus. An extraction procedure was developed for fractionation of fluorescent phenolic compounds. Chromatographic comparisons of phenolics from resistant and susceptible tissue culture lines, before and up to 6 days after inoculation, showed no significant differences in phenolic content. Ten days after inoculation there was an almost total loss of fluorescent phenolics from susceptible pieces. Comparisons of callus and leaf phenolics showed large qualitative differences between these two tissue types.