scholarly journals The hydroxylation of p-coumaric acid by an enzyme from leaves of spinach beet (Beta vulgaris L.)

1969 ◽  
Vol 113 (1) ◽  
pp. 109-115 ◽  
Author(s):  
P. F. T. Vaughan ◽  
V S Butt
Keyword(s):  
Sodium Chloride ◽  
Caffeic Acid ◽  
Beta Vulgaris ◽  
Catechol Oxidase ◽  
Purification Procedure ◽  
Coumaric Acid ◽  
Constant Ratio ◽  
Molar Basis ◽  
Tetrahydrofolic Acid ◽  
High Concentrations

1. An enzyme from the leaves of spinach beet (Beta vulgaris L.) that catalyses the hydroxylation of p-coumaric acid to caffeic acid in the presence of ascorbate has been purified about 1000-fold on a protein basis. 2. It is activated by high concentrations of ammonium sulphate and sodium chloride. 3. The preparation shows both hydroxylase and catechol oxidase activities, in a constant ratio throughout the purification procedure; they are similarly activated by salts. 4. Ascorbate acts as a reductant in quantities equivalent to the caffeic acid produced by hydroxylation. 5. Ascorbate can be replaced by tetrahydrofolic acid, NADH, NADPH or 2-amino-4-hydroxy-6,7-dimethyl-5,6,7,8-tetrahydropteridine, but not by caffeic acid. Among these, the pteridine is the most effective, but the reaction is not inhibited by aminopterin. In experiments with saturating concentrations of NADH and the pteridine, these reductants compete in the reaction and are equivalent on a molar basis. 6. No cofactor has been separated from the enzyme by prolonged dialysis. 7. The relation of the enzyme to other hydroxylases and phenolases is discussed.

scholarly journals The action of o-dihydric phenols in the hydroxylation of p-coumaric acid by a phenolase from leaves of spinach beet (Beta vulgaris L.)

1970 ◽  
Vol 119 (1) ◽  
pp. 89-94 ◽  
Author(s):  
P. F. T. Vaughan ◽  
V. S. Butt
Keyword(s):  
Caffeic Acid ◽  
Beta Vulgaris ◽  
Oxidase Activity ◽  
Maximum Rate ◽  
Specific Activity ◽  
Catechol Oxidase ◽  
Coumaric Acid ◽  
Catalytically Active ◽  
Lag Period ◽  
High Concentrations

1. Under defined conditions, the hydroxylation of p-coumaric acid catalysed by a phenolase from leaves of spinach beet (Beta vulgaris L.) was observed to develop its maximum rate only after a lag period. 2. By decreasing the reaction rate with lower enzyme concentrations or by increasing it with higher concentrations of reductants, the length of the lag period was inversely related to the maximum rate subsequently developed. 3. Low concentrations of caffeic acid or other o-dihydric phenols abolished this lag period. With caffeic acid, the rate of hydroxylation was independent of the reductant employed. 4. Hydroxylation was inhibited by diethyldithiocarbamate, but with low inhibitor concentrations hydroxylation recovered after a lag period. This lag could again be abolished by the addition of high concentrations of caffeic acid or other o-dihydric phenols. 5. Catechol oxidase activity showed no lag period, and did not recover from diethyldithiocarbamate inhibition. 6. The purified enzyme contained 0.17–0.33% copper; preparations with the highest specific activity were found to have the highest copper content. 7. The results are interpreted to suggest that the oxidation of o-dihydric phenols converts the enzymic copper into a species catalytically active in hydroxylation. This may represent the primary function for the catechol oxidase activity of the phenolase complex. The electron donors are concerned mainly, but not entirely, in the reduction of o-quinones produced in this reaction.

scholarly journals The expression of catechol oxidase activity during the hydroxylation of p-coumaric acid by spinach-beet phenolase

1972 ◽  
Vol 127 (4) ◽  
pp. 641-647 ◽  
Author(s):  
P. F. T. Vaughan ◽  
V. S. Butt
Keyword(s):  
Oxygen Consumption ◽  
Bovine Serum Albumin ◽  
Oxygen Uptake ◽  
Caffeic Acid ◽  
Bovine Serum ◽  
Acid Production ◽  
Reaction Rates ◽  
Catechol Oxidase ◽  
Coumaric Acid ◽  
Enzyme Preparations

1. The conditions under which oxygen consumption in excess of that required for the hydroxylation of p-coumaric acid to caffeic acid, catalysed by spinach-beet phenolase, can be suppressed, have been examined. 2. With dimethyltetrahydropteridine as electron donor, oxygen uptake was exactly equivalent to the caffeic acid produced, provided that p-coumaric acid was in excess, but with excess of reductant, oxygen uptake caused by the further oxidation of caffeic acid was also observed. 3. With equal concentrations of ascorbate and p-coumaric acid, equivalent oxygen uptake and caffeic acid production was found only in the first stages of the reaction, whereas with NADH substituted for ascorbate, oxygen uptake was in excess throughout. 4. When ascorbate was used, the period of the reaction over which this equivalence was found was decreased at high reaction rates and not observed at all with aged enzyme preparations; equivalence was restored by adding bovine serum albumin to these aged preparations. 5. Equivalence between oxygen consumption and caffeic acid production was observed with NADH, if small quantities of dimethyltetrahydropteridine were also added. 6. It is concluded that hydroxylation proceeds without the concomitant production of caffeic acid only if the enzyme is stabilized for hydroxylation by p-coumaric acid and the reductant, and is protected from attack by o-quinones.

ABOLITION OF MAGNESIUM-INDUCED HYPOCALCAEMIA BY ACUTE THYRO-PARATHYROIDECTOMY IN THE CAT

1970 ◽  
Vol 64 (1) ◽  
pp. 150-158 ◽  
Author(s):  
S. Pors Nielsen
Keyword(s):  
Sodium Chloride ◽  
Flow Rate ◽  
Magnesium Chloride ◽  
Calcium Concentration ◽  
Plasma Calcium ◽  
Magnesium Concentration ◽  
Isotonic Sodium Chloride ◽  
Plasma Calcium Concentration ◽  
High Concentrations ◽  
Plasma Magnesium

ABSTRACT Intravenous infusion of isotonic magnesium chloride into young cats with a resultant mean plasma magnesium concentration of 7.7 meq./100 g protein was followed by a significant lowering of the plasma calcium concentration in 90 minutes. The rate of decrease of plasma calcium is consistent with the hypothesis that calcitonin is released by magnesium in high concentrations. There was no decrease in the plasma calcium concentration in cats of the same weight thyroparathyroidectomized 60 min before an identical magnesium chloride infusion or an infusion of isotonic sodium chloride at the same flow rate. The hypercalciuric effect of magnesium could not account for the hypocalcaemic effect of magnesium. Plasma magnesium concentration during magnesium infusion into cats with an intact thyroid-parathyroid gland complex was slightly, but not significantly higher than in acutely thyroparathyroidectomized cats.

scholarly journals A Simple Method for Evaluating the Bioactive Phenolic Compounds’ Presence in Brazilian Craft Beers

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4716
Author(s):  
Marcelo Coelho Silva ◽  
Jeancarlo Pereira dos Anjos ◽  
Lilian Lefol Nani Guarieiro ◽  
Bruna A. Souza Machado
Keyword(s):  
Phenolic Compounds ◽  
Caffeic Acid ◽  
Good Accuracy ◽  
Limit Of Detection ◽  
Coumaric Acid ◽  
Simple Method ◽  
Craft Beer ◽  
Extraction Step ◽  
Satisfactory Precision ◽  
Craft Beers

There are a significant number of analytical methodologies employing different techniques to determine phenolic compounds in beverages. However, these methods employ long sample preparation processes and great time consumption. The aim of this paper was the development of a simple method for evaluating the phenolic compounds’ presence in Brazilian craft beers without a previous extraction step. Catechin, caffeic acid, epicatechin, p-coumaric acid, hydrated rutin, trans-ferulic acid, quercetin, kaempferol, and formononetin were analyzed in fifteen different craft beers. The method showed good linearity (R2 ≥ 0.9966). The limit of detection ranged from 0.08 to 0.83 mg L−1, and limits of quantification were between 0.27 and 2.78 mg L−1. The method showed a satisfactory precision (RSD ≤ 16.2%). A good accuracy was obtained by the proposed method for all phenolic compounds in craft beer (68.6% ˂ accuracy ˂ 112%). Catechin showed higher concentrations (up to 124.8 mg L−1) in the samples, followed by epicatechin (up to 51.1 mg L−1) and caffeic acid (up to 8.13 mg L−1). Rutin and formononetin were observed in all analyzed samples (0.52 mg L−1 to 2.40 mg L−1), and kaempferol was less present in the samples. The presence of plant origin products was determinant for the occurrence of the highest concentrations of phenolic compounds in Brazilian craft beers.

scholarly journals Relationships Between the Content of Phenolic Compounds and the Antioxidant Activity of Polish Honey Varieties as a Tool for Botanical Discrimination

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1810
Author(s):  
Monika Kędzierska-Matysek ◽  
Małgorzata Stryjecka ◽  
Anna Teter ◽  
Piotr Skałecki ◽  
Piotr Domaradzki ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Caffeic Acid ◽  
Principal Component ◽  
Total Content ◽  
Component Analysis ◽  
Total Phenolic ◽  
Hydroxybenzoic Acid ◽  
Coumaric Acid

The study compared the content of eight phenolic acids and four flavonoids and the antioxidant activity of six Polish varietal honeys. An attempt was also made to determine the correlations between the antioxidant parameters of the honeys and their polyphenol profile using principal component analysis. Total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity (ABTS) and reduction capacity (FRAP) were determined spectrophotometrically, and the phenolic compounds were determined using high-performance liquid chromatography (HPLC). The buckwheat honeys showed the strongest antioxidant activity, most likely because they had the highest concentrations of total phenols, total flavonoids, p-hydroxybenzoic acid, caffeic acid, p-coumaric acid, vanillic acid and chrysin. The principal component analysis (PCA) of the data showed significant relationships between the botanic origin of the honey, the total content of phenolic compounds and flavonoids and the antioxidant activity of the six Polish varietal honeys. The strongest, significant correlations were shown for parameters of antioxidant activity and TPC, TFC, p-hydroxybenzoic acid, caffeic acid and p-coumaric acid. Analysis of four principal components (explaining 86.9% of the total variance), as a classification tool, confirmed the distinctiveness of the Polish honeys in terms of their antioxidant activity and content of phenolic compounds.

METABOLISM OF PHENYLPROPANOID COMPOUNDS IN SALVIA: II. BIOSYNTHESIS OF PHENOLIC CINNAMIC ACIDS

1959 ◽  
Vol 37 (1) ◽  
pp. 537-547 ◽  
Author(s):  
D. R. McCalla ◽  
A. C. Neish
Keyword(s):  
Caffeic Acid ◽  
Phenolic Acids ◽  
Cinnamic Acid ◽  
Shikimic Acid ◽  
Sinapic Acid ◽  
Coumaric Acid ◽  
Cinnamic Acids ◽  
Phenyllactic Acid ◽  
Salvia Splendens ◽  
Specific Activities

p-Coumaric, caffeic, ferulic, and sinapic acids were found to occur in Salvia splendens Sello in alkali-labile compounds of unknown constitution. A number of C14-labelled compounds were administered to leafy cuttings of salvia and these phenolic acids were isolated after a metabolic period of several hours and their specific activities measured. Cinnamic acid, dihydrocinnamic acid, L-phenylalanine, and (−)-phenyllactic acid were found to be good precursors of the phenolic acids. D-Phenylalanine, L-tyrosine, and (+)-phenyllactic acid were poor precursors. A kinetic study of the formation of the phenolic acids from L-phenylalanine-C14 gave data consistent with the view that p-coumaric acid → caffeic acid → ferulic acid → sinapic acid, and that these compounds can act as intermediates in lignification. Feeding of C14-labelled members of this series showed that salvia could convert any one to a more complex member of the series but not so readily to a simpler member. Caffeic acid-β-C14 was obtained from salvia after the feeding of L-phenylalanine-β-C14 or cinnamic acid-β-C14, and caffeic acid labelled only in the ring was obtained after feeding generally labelled shikimic acid.

The effect of salinity on the growth, water status, and ion content on Common bean (Phaseolus vulgaris. L. var. El-Djadida)

2018 ◽  
Vol 7 (4) ◽  
pp. 147-156
Author(s):  
Laredj-Zazou Rahma ◽  
Toumi Benali Fawzia ◽  
Bouazza Sofiane
Keyword(s):  
Sodium Chloride ◽  
Water Status ◽  
Phaseolus Vulgaris L ◽  
Salt Stress Tolerance ◽  
Ion Content ◽  
Organic Growth ◽  
Growth Attributes ◽  
High Concentrations ◽  
High Level ◽  
Post Stress

Stress salinity has an important effect on crops physiology. The scope of our study was to evaluate the effect of salt stress tolerance as determined through growth attributes, water status and ion content in (Phaseolus vul-garis. L), the variety of El-Djadida in 6 weeks post stress application. The ex-periment was performed under glasshouse, in controlled conditions, in pots and irrigated with nutrient solution of Hoagland. Plants were irrigated with water containing sodium chloride alone (100 and 200 meq.l-1) combined with sodium chloride (NaCl) and calcium chloride (CaCl2) (100 and 150 meq.l-1). The results obtained showed that the salt application had a depressive effect on the organic growth however, this trend was dependant on the intensity of the stress. The hydric state of the plant varied with the concentration of sub-strate, thus exhibiting the ability to moderate the sensitive plant to adjust gradually to their osmotic pressure even by maintaining high concentrations of K+. The distribution of Na+, K+ and Ca++ in plant organs leaves and roots highlighted that the high level of salinity increased with levels of Na+ which inhibited the absorption of Ca++ and K+ ions.

scholarly journals The Effect of Salinity on Fruit Quality and Yield of Cherry Tomatoes

Horticulturae ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 59
Author(s):  
Carlos Agius ◽  
Sabine von Tucher ◽  
Wilfried Rozhon
Keyword(s):  
Sodium Chloride ◽  
Fruit Quality ◽  
Plant Pathogens ◽  
Titratable Acidity ◽  
Sodium Content ◽  
Soluble Solids ◽  
Glucose Levels ◽  
High Concentrations ◽  
Cherry Tomatoes

Hydroponic cultivation of vegetables avoids problems with soil-borne plant pathogens and may allow higher yield. In arid climates and particularly on islands, high concentrations of sodium chloride can be present in the groundwater. For instance, in many sites of Malta, the groundwater contains more than 10 mM sodium chloride. Here we investigated the effects of sodium chloride at levels typically found in Malta on yield, physiology and fruit quality of tomato, the economically most important vegetable. We selected cherry tomatoes since their production is attractive due to their high marketing value. While the yield declined at higher salinity levels tested (17 and 34 mM), the quality increased significantly as indicated by higher total soluble solids and fructose and glucose levels. The type of substrate—coco peat, perlite or Rockwool—had only minor effects. Although the concentration of citric acid and malic acid remained unaffected, the pH dropped by approximately 0.1 unit and the titratable acidity increased slightly. This might be explained by a high uptake of chloride but a lower increase of the sodium content and a reduced potassium level in the fruits, shifting the equilibrium of the organic acids more to their protonated forms. Proline increased significantly, while the level of glutamic acid, which is crucial for the taste, remained unchanged. Our results show that cherry tomatoes can be cultivated in nutrient solutions prepared with salt-containing groundwater, as found in Malta. The yield declined to some extent but the quality of the produced fruits was higher compared to cultivation in salt-free media.

scholarly journals Roles of citrus secondary metabolites in tree and fruit defence against pests and pathogens

2021 ◽  
Vol 1 (2) ◽  
pp. 51-62
Author(s):  
Ibrahim Kahramanoglu ◽  
Serhat Usanmaz
Keyword(s):  
Secondary Metabolites ◽  
Human Health ◽  
Caffeic Acid ◽  
Positive Impact ◽  
Plant Defence ◽  
Background Information ◽  
Diverse Group ◽  
Coumaric Acid ◽  
Horticultural Crops ◽  
Potential Benefits

Plants have evolved several mechanisms to protect themselves from different biotic and abiotic challenges, including pest and pathogen attacks. One of the most important mechanisms is the secondary metabolites (SM) (terpenes, phenolics and nitrogen/sulphur-containing compounds). The plants have synthesised a diverse group of compounds in different concentrations (mostly in very small quantities) and have important roles in plant defence, survival, adaptation, and reproduction. Citrus crops are among the most essential cultivated fruit groups and are rich in terpenoids and phenolics. Besides the well-known benefits of these compounds on human health, they have a significant role in plant/fruit defence against biotic and abiotic challenges. This review aims to highlight the importance of these compounds (such as limonene, citral, saponin, hesperidin, quercetin, tangeritine, caffeic acid, p-coumaric acid, scoparone, etc.) and discuss their roles in tree and fruit defence against pests and pathogens. In today’s world, where there is an essential human impact on nature, a need is raised to reduce pesticides against pests and pathogens. Therefore, understanding the roles of these SM and their induction is believed to have a significant positive impact on the production and/or storage of horticultural crops and may help reduce the use of synthetic agrochemicals. In line with this information, present review was aimed to provide a background information for researchers, farmers, horticulturalists and technology developers about the potential benefits of SM on plant/fruit defence and a guideline about their induction.

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