scholarly journals Studies on the Enzymic Browning of Apples II. Properties of Apple Polyphenoloxidase

1964 ◽  
Vol 17 (2) ◽  
pp. 360 ◽  
Author(s):  
JRL Walker
Keyword(s):  
Phenolic Compounds ◽  
Chlorogenic Acid ◽  
Apple Fruit ◽  
Thiol Compounds ◽  
Enzymic Browning ◽  
Young Apple

The properties of a particulate polyphenoloxidase preparation from young apple fruit have been investigated. Chlorogenic acid, D-catechin, and hydrocaffeic acid were found to be the substrates most rapidly oxidized by this preparation, but its action on a number of other phenolic compounds was also investigated. The inhibition of the oxidation of phenolic compounds by cysteine and other thiol compounds was studied in detail.

scholarly journals Comparison of free and bound phenolic compositions and antioxidant activities of leaves from different mulberry varieties

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Zhenjiang Wang ◽  
Cuiming Tang ◽  
Gengsheng Xiao ◽  
Fanwei Dai ◽  
Sen Lin ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Chlorogenic Acid ◽  
Antioxidant Activities ◽  
Syringic Acid ◽  
Mulberry Leaves ◽  
Phenolic Substances ◽  
Further Development ◽  
Active Substances ◽  
Phenolic Extracts

AbstractMulberry leaves are used in traditional Chinese medicine and contain numerous active substances that are known to be beneficial for human health. The aim of this study was to investigate the phenolic compositions and antioxidant activities of the leaves from 23 mulberry cultivars. Qualitative LC-ESI-QTOF analysis revealed the presence of 11 phenolic compounds in the free phenolic extracts and 10 phenolic compounds in the bound fractions. Chlorogenic acid and caffeic acid were the major components in the free and bound fractions, respectively. The results revealed that the changguosang cultivar from Taiwan contained the greatest content of phenolic compounds as well as the highest antioxidant activity among the 23 cultivars examined, as determined using three separate antioxidant assays. The isoquercitrin, chlorogenic acid, and rutin contents of the free phenolic extracts displayed significant correlations with the antioxidant activities, while syringic acid and rutin were the main contributors to the antioxidant activities of the bound phenolic fractions. The obtained results demonstrate that mulberry leaves contain a variety of beneficial phenolic substances and may be suitable for further development as a herbal medicine.

scholarly journals Microwave-Assisted Extraction of Phenolics from Hibiscus sabdariffa Flowers: Method Development and Validation

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 51
Author(s):  
Rohmah Nur Fathimah ◽  
Widiastuti Setyaningsih ◽  
Ceferino Carrera ◽  
Miguel Palma
Keyword(s):  
Phenolic Compounds ◽  
Chlorogenic Acid ◽  
Caffeic Acid ◽  
Solvent Composition ◽  
Positive Contribution ◽  
Hibiscus Sabdariffa ◽  
Microwave Assisted Extraction ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Development And Validation

Phenolics are bioactive compounds already reported in Hibiscus sabdariffa (roselle). The present study reports the development and validation of the analytical microwave-assisted extraction (MAE) method for the determination of phenolic compounds in roselle flowers to establish their positive contribution to human health. Prior to the optimization, a study for identifying phenolic compounds revealed that chlorogenic acid, protocatechuic acid, caffeic acid, and rutin were presented in Roselle. Three factors affecting MAE, viz. temperature, solvent composition, and sample to solvent ratio, were optimized employing a Box-Behnken Design (BBD) in conjunction with response surface methodology (RSM). The maximum extraction recovery was achieved using the extraction temperature of 68 °C, solvent composition of 59% MeOH in water, and 20:1 solvent to sample ratio. The kinetics experiment confirmed full recoveries (92–119%) at 15 min. Subsequently, method validation showed a satisfactory result, including low detection limits from 0.219 mg L−1 (caffeic acid) to 0.374 mg L−1 (chlorogenic acid). Both precisions and accuracy met the acceptances by AOAC. Finally, the method was successfully applied to quantify phenolics in the two most common varieties of Roselle. Chlorogenic acid was found as the main phenolic compound in both varieties

Chlorogenic Acid and the Enzymic Browning of Apples and Pears

Nature ◽  
1953 ◽  
Vol 172 (4380) ◽  
pp. 678-678 ◽  
Author(s):  
C. WEURMAN ◽  
T. SWAIN
Keyword(s):  
Chlorogenic Acid ◽  
Enzymic Browning

scholarly journals Changes in Elderberry (Sambucus nigra L.) Juice Concentrate Polyphenols during Storage

2021 ◽  
Vol 11 (15) ◽  
pp. 6941
Author(s):  
Cláudia M. B. Neves ◽  
António Pinto ◽  
Fernando Gonçalves ◽  
Dulcineia F. Wessel
Keyword(s):  
Phenolic Compounds ◽  
Chlorogenic Acid ◽  
Total Phenolic Content ◽  
Room Temperature ◽  
Phenolic Content ◽  
Total Phenolic ◽  
Sambucus Nigra ◽  
Juice Concentrate ◽  
Rutin And Quercetin ◽  
Polymeric Color

Elderberry (Sambucus nigra L.) juice concentrate is highly rich in polyphenols, particularly anthocyanins and flavonols, which have been associated with a wide range of health-promoting properties. Phenolic compounds, in particular anthocyanins, are unstable and may change during storage, which might influence the product color quality and its potential health effects. The aim of this study was to evaluate the changes in the polyphenols profile of elderberry juice concentrate produced at an industrial scale during seven months of storage at 5 °C and at room temperature. The total phenolic content, the total monomeric anthocyanins, the percent polymeric color, and the ABTS•+ scavenging activity were monitored over time. In addition, the profile and content of the main individual phenolic compounds were also assessed by HPLC-DAD. The results show that cyanidin-3-O-sambubioside, cyanidin-3-O-glucoside, cyanidin-3-O-sambubioside-5-O-glucoside, cyanidin-3,5-O-diglucoside, chlorogenic acid, rutin, and quercetin-3-O-glucoside were the main phenolic compounds identified. Storage at room temperature resulted in a strong reduction in total monomeric anthocyanin content accompanied by an increase in percent polymeric color values. Cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside degraded faster than cyanidin-3,5-O-diglucoside and cyanidin-3-O-sambubioside-5-O-glucoside. Concentration of chlorogenic acid also decreased over storage, whereas rutin and quercetin-3-O-glucoside were quite stable. Storage at 5 °C caused a lower impact on the contents of anthocyanins and chlorogenic acid and the percent polymeric color was not affected. The total phenolic content and the in vitro antioxidant activity remained quite similar over the time, for both temperatures, suggesting that elderberry concentrates still preserve their health benefits of antioxidant capacity after seven months of storage.

scholarly journals A Phenolic Fraction from Catharanthus roseus L. Stems Decreases Glycemia and Stimulates Insulin Secretion

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Janet Alejandra Espejel-Nava ◽  
Elisa Vega-Avila ◽  
Francisco Alarcon-Aguilar ◽  
Alejandra Contreras-Ramos ◽  
Guadalupe Díaz-Rosas ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Phenolic Compounds ◽  
Chlorogenic Acid ◽  
Gallic Acid ◽  
Catharanthus Roseus ◽  
Chromatographic Analysis ◽  
Hypoglycemic Effect ◽  
Diabetic Mice ◽  
Rinm5f Cells ◽  
Phenolic Fraction

Catharanthus roseus (L.) G. (C. roseus) is a medicinal plant used traditionally for diabetes mellitus control. Several compounds of an alkaloidal nature have been proposed as hypoglycemic principles. However, little attention has been paid to other compounds in this plant that could also participate in this hypoglycemic activity. This study aimed to analyze the hypoglycemic effect of a polyphenolic fraction from C. roseus, as well as its action on insulin secretion and expression in RINm5F cells. Methods. An alkaloid-free aqueous extract was obtained from C. roseus stems. The hypoglycemic effect of different doses of this extract was evaluated in normal and streptozotocin-induced diabetic mice. This extract was fractionated by bipartition, and the resultant fractions were assessed by their hypoglycemic effects. Subsequently, the fraction with the greater hypoglycemic activity was added to the RINm5F cells, and the expression and secretion of insulin were analyzed. The antioxidant activity was determined by the DPPH method and through chromatographic analysis of the most active fraction by HPLC, using an Econosphere C18 column. Results. The aqueous alkaloid-free extract of C. roseus stems significantly reduced blood glucose in normal and diabetic mice. The fractionation of this extract provided three fractions, one of which (a precipitate) showed significant reductions in glycemia at 6 h (48.1 and 64.5% in normal and diabetic mice, respectively). This precipitate contained phenolic compounds and saponins. Its chromatographic analysis showed that it is formed by several phenolic compounds; gallic acid (0.053%) and chlorogenic acid (0.216%) were identified and quantified. Conclusion. The phenolic fraction of C. roseus containing gallic acid and chlorogenic acid had a hypoglycemic effect that may be explained by an increase in insulin secretion.

scholarly journals Evidences for Chlorogenic Acid — A Major Endogenous Polyphenol Involved in Regulation of Ripening and Senescence of Apple Fruit

PLoS ONE ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. e0146940 ◽  
Author(s):  
Yu Xi ◽  
Dai Cheng ◽  
Xiangquan Zeng ◽  
Jiankang Cao ◽  
Weibo Jiang
Keyword(s):  
Chlorogenic Acid ◽  
Apple Fruit

scholarly journals Variety and Year Impact on Phenolic Content of Arkansas-Grown Sweetpotato Leaves

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 371-371
Author(s):  
Josue Bolanos ◽  
Sun-Ok Lee ◽  
Luke Howard ◽  
Cindi Brownmiller ◽  
Shahidul Islam ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Antioxidant Capacity ◽  
Chlorogenic Acid ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Statistical Significance ◽  
Radical Scavenging ◽  
Dry Weight ◽  
Antioxidant Potential ◽  
Total Phenolic

Abstract Objectives Sweetpotato leaf (SPL) is a natural source of phenolic compounds with potential utility as an antioxidant. The study aimed to measure the impacts of the years on SPL total phenolic content and antioxidant capacity and to identify and quantify the individual phenolic compounds. Methods Sweetpotato leaves in 2018 (27 varieties) and 2019 (24 varieties) were grinded and lyophilized. Phenolic compounds were extracted with 70% ethanol from SPLs. Total phenolic content was determined by Folin-Ciocalteu method and antioxidant potential was determined by DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. Five SPL samples with statistically highest antioxidant capacity were identified and quantified by HPLC. All statistical analyses were carried out by SAS software using ANOVA. Statistical significance was accepted at P < 0.05. Results The average of total phenolic contents in 2018 SPL samples was 43 ± 13 mg gallic acid equivalent (GAE)/g dry weight (DW) SPL whereas in 2019, it was 53 ± 9 mg GAE/g dry weight SPL. Antioxidant capacity in 2018 was 110 ± 75 µmol Trolox equivalent (TE)/g dry weight SPL whereas in 2019, it was 132 ± 32 µmol TE/g dry weight SPL. SPL1 had the highest antioxidant potential, followed by SPL9, SPL3, SPL28, and SPL11 (P < 0.05). The concentrations of major identified phenolics from the five SPL samples (#1, 9, 3, 28, and 11) in dry weight of SPL were: chlorogenic acid at 3.05 ± 0.35 mg/g, 5-monocaffeoylquinic acid (CQA) at 0.71 ± 0.06 mg chlorogenic acid equivalent (ChAE)/g, 4-CQA at 0.99 ± 0.07 mg ChAE/g, 3,4-diCQA at 1.22 ± 0.18 mg ChAE/g, 3,4,5-triCQA at 1.2 ± 0.18 mg ChAE/g, and 3,5-diCQA at 15.5 ± 4.05 mg ChAE/g. 3,5-diCQA, the predominant phenolic, was present in the highest amounts in SPL1. Conclusions The results showed that sweetpotato leaves collected in 2019 contained higher total phenolics and antioxidant capacity than the ones collected in 2018. Phenolic compounds have strong antioxidant activity in Arkansas-grown sweetpotato leaves. This study warrants further investigation of sweetpotato leaves to be utilized as an antioxidant. Funding Sources The work was supported by USDA-NIFA.

scholarly journals Spectrophotometric and Smartphone-Assisted Determination of Phenolic Compounds Using Crude Eggplant Extract

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4407 ◽  
Author(s):  
M.A. Morosanova ◽  
A.S. Bashkatova ◽  
E.I. Morosanova
Keyword(s):  
Phenolic Compounds ◽  
Chlorogenic Acid ◽  
Caffeic Acid ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Biological Fluids ◽  
Low Cost ◽  
Analytical Signal ◽  
Polyphenol Oxidase Activity

In order to develop a simple, reliable and low cost enzymatic method for the determination of phenolic compounds we studied polyphenol oxidase activity of crude eggplant (S. melongena) extract using 13 phenolic compounds. Catechol, caffeic and chlorogenic acids, and L-DOPA have been rapidly oxidized with the formation of colored products. Monophenolic compounds have been oxidized at a much slower speed. Ferulic acid, quercetin, rutin, and dihydroquercetin have been found to inhibit polyphenol oxidase activity of crude eggplant extract. The influence of pH, temperature, crude eggplant extract amount, and 3-methyl-2-benzothiazolinone hydrazone (MBTH) concentration on the oxidation of catechol, caffeic acid, chlorogenic acid, and L-DOPA has been investigated spectrophotometrically. Michaelis constants values decrease by a factor of 2 to 3 in the presence of MBTH. Spectrophotometric (cuvette and microplate variants) and smartphone-assisted procedures for phenolic compounds determination have been proposed. Average saturation values (HSV color model) of the images of the microplate wells have been chosen as the analytical signal for smartphone-assisted procedure. LOD values for catechol, caffeic acid, chlorogenic acid, and L-DOPA equaled 5.1, 6.3, 5.8 and 30.0 µM (cuvette procedure), 12.2, 13.2, 13.2 and 80.4 µM (microplate procedure), and 23.5, 26.4, 20.8 and 120.6 µM (smartphone procedure). All the variants have been successfully applied for fast (4-5 min) and simple TPC determination in plant derived products and L-DOPA determination in model biological fluids. The values found with smartphone procedure are in good agreement with both spectrophotometric procedures values and reference values. Using crude eggplant extract- mediated reactions combined with smartphone camera detection has allowed creating low-cost, reliable and environmentally friendly analytical method for the determination of phenolic compounds.

Comparison of polyphenols and related enzymes in the capsule and nodal tumor of Nicotiana plants

1974 ◽  
Vol 52 (6) ◽  
pp. 1379-1385 ◽  
Author(s):  
S. J. Sheen ◽  
R. A. Andersen
Keyword(s):  
Cell Proliferation ◽  
Phenolic Compounds ◽  
Nicotiana Tabacum ◽  
Chlorogenic Acid ◽  
Dry Weight ◽  
In Situ Synthesis ◽  
Floral Tissue ◽  
Similar Composition ◽  
Tumor Tissues

Extracts of capsules of Nicotiana tabacum cv. Burley 21 and nodal tumors and capsules of a genetically tumor-prone amphiploid N. suaveolens × N. langsdorffii had a similar composition of phenolic compounds. Dihydroxyphenols, predominantly chlorogenic acid, accumulated to 4% and 13% of the dry weight in the young and old tumors, respectively. In situ synthesis of chlorogenic acid in tumor tissues was demonstrated by incorporation of L-phenylalanine-U-14C. Quantities of polyphenols also increased as floral tissue developed from fertilized flower to capsule. The immature capsule and tumor tissues contained more polyphenoloxidase but less peroxidase than the leaf. Peroxidase zymograms, soluble proteins, and alkaloids in tumor extracts resembled those in capsule extracts. It is suggested that these biochemical similarities may reflect a common mode for the regulation of cell proliferation in tobacco capsules and nodal tumors.

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