scholarly journals Antioxidant activity and mechanism of action of some synthesised phenolic acid amides of aromatic amines

2013 ◽  
Vol 31 (No. 1) ◽  
pp. 5-13 ◽  
Author(s):  
E. Marinova ◽  
L. Georgiev ◽  
I. Totseva ◽  
K. Seizova ◽  
T. Milkova
Keyword(s):  
Antioxidant Activity ◽  
Caffeic Acid ◽  
Mechanism Of Action ◽  
Sunflower Oil ◽  
Aromatic Amines ◽  
Kinetic Data ◽  
Side Reaction ◽  
Hydroxyl Groups ◽  
Direct Oxidation ◽  
Derivatives Of

The antioxidative activities and mechanism of action were studied of eight synthesised cinnamoyl- and hydroxycinnamoyl amides of biogenic amines (caffeoyldopamine, cinnamoyldopamine, p-coumaroyldopamine, feruloyldopamine, sinapoyldopamine, caffeoylphenylethylamine, caffeoyltyramine, and caffeoyltryptamine) in a wide concentration range (2.5&ndash;20 &times; 10<sup>&ndash;4</sup>M) during autoxidation of triacylglycerols of sunflower oil. It was established that all amides exhibited excellent antioxidant activity, higher than or comparable with that of caffeic acid. The best activity was shown by caffeoyldopamine followed by cinnamoyldopamine and caffeoyltyramine. The analysis of the kinetic data obtained showed that the presence of hydroxyl groups in the amino part (derivatives of dopamine and tyramine) led to direct oxidation of the molecules during the process and stabilisation of the resulting radicals. In contrast, the amides without hydroxyl groups in the amino part participated in the side reaction with peroxides and the resulting radicals took part in one side reaction of the chain propagation as did caffeic acid. &nbsp;

scholarly journals Synthesis and Antioxidant Activity of Caffeic Acid Derivatives

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2199 ◽  
Author(s):  
Katarzyna Sidoryk ◽  
Anna Jaromin ◽  
Nina Filipczak ◽  
Piotr Cmoch ◽  
Marcin Cybulski
Keyword(s):  
Organic Chemistry ◽  
Antioxidant Activity ◽  
Caffeic Acid ◽  
Wittig Reaction ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Water Medium ◽  
One Pot ◽  
Safe Alternative ◽  
Caffeic Acid Derivatives

A series of caffeic acid derivatives were synthesized via a modified Wittig reaction which is a very important tool in organic chemistry for the construction of unsaturated carbon–carbon bonds. All reactions were performed in water medium at 90 °C. The aqueous Wittig reaction worked best when one unprotected hydroxyl group was present in the phenyl ring. The olefinations in the aqueous conditions were also conducted with good yields in the presence of two unprotected hydroxyl groups. When the number of the hydroxyl groups was increased to three, the reaction yields were worse, and the derivatives 12, 13, and 18 were obtained with 74%, 37%, and 70% yields, respectively. Nevertheless, the Wittig reaction using water as the essential medium is an elegant one-pot synthesis and a greener method, which can be a safe alternative for implementation in organic chemistry. The obtained compounds were tested for their antioxidant activity, and 12, 13, and 18 showed the highest activities. Moreover, all synthesized compounds displayed no cytotoxicity, and can therefore be used in the pharmaceutical or cosmetic industry.

scholarly journals An Overview of Bioactive Alkaloid, Semi-Synthetic Analogs, Mechanism of Action and Structure-Activity Relationship of Piperine as Antioxidant

2021 ◽  
Vol 33 (9) ◽  
pp. 2244-2250
Author(s):  
Sagar Joshi ◽  
Salahuddin ◽  
Rajnish Kumar ◽  
Divya Sharma
Keyword(s):  
Antioxidant Activity ◽  
Mechanism Of Action ◽  
Structure Activity Relationship ◽  
Black Pepper ◽  
Activity Relationship ◽  
Pharmacological Activities ◽  
Structure Activity ◽  
Natural Alkaloid ◽  
Relationship Of ◽  
Derivatives Of

Piperine, a natural alkaloid obtained from black pepper exhibit a variety of pharmacological activities like antioxidant activity and in this article, the mechanism of the antioxidant, structure-activity relationship of piperine as an antioxidant and various schemes of derivatives of piperine as antioxidants were discussed.

scholarly journals Antioxidant activity of some coumarins / Antioxidačná activita niektorých kumarínov

2015 ◽  
Vol 62 (s9) ◽  
pp. 41-45 ◽  
Author(s):  
F. Šeršeň ◽  
M. Lácová
Keyword(s):  
Antioxidant Activity ◽  
Acetic Acid ◽  
Superoxide Anion ◽  
The Other ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Coumarin Derivatives ◽  
Antioxidant Effectiveness ◽  
Derivatives Of ◽  
Superoxide Anion Radicals

AbstractNineteen derivatives of coumarin were tested on the scavenging of 2,2-diphenyl-1-picrylhydrazyl, hydroxyl and superoxide anion radicals. It was found that antioxidant activity exhibits only such coumarins that contain hydroxyl groups. The derivatives without hydroxyl group showed very low antioxidant effectiveness or they were ineffective. On the other hand, the greatest antioxidant effectiveness was exhibited by coumarin derivatives that contained hydroxyl groups in 6 or 8 position, whereas the effectiveness of derivatives with one hydroxyl group in 4, 5 or 7 position was very low. Based on scavenging of the above-mentioned radicals, it was found that the most effective scavengers were 7,8-dihydroxy-4-methylcoumarin (i.e. compound that contains two hydroxyl groups in 7 and 8 positions), (7,8-dihydroxy-2-oxo-2H-chromen-4-yl)acetic acid (this compound contains in addition to two hydroxyl groups in 7 and 8 positions also one hydroxyl group in the acidic residue), esculetin (6,7-dihydroxycoumarin) and 6,7-dihydroxy-4-methylcoumarin.

scholarly journals Butylated methyl caffeate: a novel antioxidant

2020 ◽  
Vol 71 (2) ◽  
pp. 352
Author(s):  
Q. Q. Chen ◽  
H. Pasdar ◽  
X. C. Weng
Keyword(s):  
Antioxidant Activity ◽  
Caffeic Acid ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
The Other ◽  
Lipid Phase ◽  
Hydroxyl Groups ◽  
Dpph Radical ◽  
Methyl Caffeate ◽  
Dpph Radical Scavenging

A novel caffeic acid derivative, butylated methyl caffeate (BMC), was synthesized via esterification between butylated caffeic acid (BCA) and methanol. Its antioxidant activity was investigated and compared to TBHQ, caffeic acid (CA), methyl caffeate (MC) and BCA through deep-frying, an oven test in oil-in-water emulsions and DPPH radical scavenging. BMC showed the strongest antioxidant activity among the five anti­oxidants in emulsions and its antioxidant activity was almost as strong as BCA in frying. Its soybean oil-water partition coefficient was 9.18 due to its ester and tert-butyl groups, far greater than those of MC (4.82), BCA (2.41), CA (0.84) and TBHQ (3.22). This meant that it was much more soluble in the lipid phase than the other four antioxidants in emulsions. The DPPH radical scavenging activity of BMC was near TBHQ, lower than the other three because of its steric hindrance and less functional phenolic hydroxyl groups compared to others when their masses were the same.

scholarly journals Fructans, Polyphenols and Antioxidant Activity in Edible Roots and Thistles from Seven Medicinal Plants

2021 ◽  
Vol 20 (4) ◽  
Author(s):  
Nadezhda Petkova ◽  
◽  
Ivanka Hambarlyiska ◽  
Elena Angelova ◽  
Ivan Ivanov ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Medicinal Plants ◽  
Caffeic Acid ◽  
Phenolic Content ◽  
Total Flavonoids ◽  
Total Phenols ◽  
High Antioxidant Activity ◽  
Edible Roots ◽  
Ethanol Extracts ◽  
Derivatives Of

Abstract The research purposed to evaluate the bioactive compounds and antioxidant content in water and 50 % ethanol extracts from different vegetal parts of seven herbs (black bryony, dandelion, leuzea, asparagus, St. Benedict's thistle, cotton thistle, and sarsaparilla). Sugars and total fructans (inulin ad fructooligosacchrides (FOS) were analysed by spectrophotometric and chromatographic methods. The total phenols, total flavonoids and derivatives of caffeic acid were also determined. The antioxidant activity was evaluated by DPPH and FRAP methods. Inulin and FOS were detected only in three plants (leuzea, dandelion and the cotton thistle). Dandelion roots were evaluated as the richest source of total fructans (18 g/100 g dw). The highest phenolic content was found in sarsaparilla roots 50 % ethanol extracts (21 mg GAE/g dw). Leuzea roots were evaluated as a rich source of dihydroxycinnamic acid derivatives and flavonoids. The high antioxidant activity demonstrated sarsaparilla water extracts, followed by water and 95 % ethanol of leuzea roots and cotton thistle flowеring heads (20-98 mM TE/g dw). The study demonstrated the use of some medicinal plants (especially leuzea, sarsaparilla and cotton thistle) as sources of antioxidants and inulin-type fructans in food and beverages. Keywords: Antioxidant Activity, Fructan, Medicinal Plants, Polyphenols

Comparison of Bioactive Compounds of Matricaria recutita Extracted by Ultrasound and Maceration and their Effects on Preventing Sunflower Oil During Frying

2019 ◽  
Vol 15 (2) ◽  
pp. 156-164 ◽  
Author(s):  
Reza Farahmandfar ◽  
Maryam Asnaashari ◽  
Yegane Asadi ◽  
Batool Beyranvand
Keyword(s):  
Antioxidant Activity ◽  
Gallic Acid ◽  
Bioactive Compounds ◽  
Sunflower Oil ◽  
Radical Scavenging ◽  
Stability Index ◽  
Acid Value ◽  
Extraction Methods ◽  
Oil Stability Index ◽  
Matricaria Recutita

Background: It is important to study about the use of natural antioxidants as alternatives to synthetic ones due to the possibility of carcinogenic effects of synthetic antioxidants. This study is comparing the effect of the ultrasound-assisted and maceration extraction methods on antioxidant activity of Matricaria recutita. Methods: Bioactive compounds including phenolic, tocopherol, flavonoid and tannins and antioxidant activity of the extracts were evaluated. Moreover, extracts obtained from ultrasound and maceration methods were added to sunflower oil without any antioxidants at level of 200, 500 and 800 ppm, after that samples were heated at 180°C. Oxidation of the samples were evaluated after 0, 4, 8, 12, 16, 20 and 24 hours by measuring Peroxide Value (PV), Conjugated Diene (CD), Iodine Value (IV), Carbonyl Value (CV), Total Polar Compounds (TPC), Oil Stability Index (OSI), Color Index (CI) and acid value (AV). Results: The result showed total phenol (42.90 mg gallic acid/g extract), tocopherol (120.46 &#181;g &#945; - tocopherol/ml extract), flavonoid (2.64 mg/100 g extract) and tannins (3.89 mg gallic acid/g extract) of ultrasound extracts were higher than maceration extracts. Antioxidant activity of the extract was evaluated by DPPH assay which indicated 800 ppm of the Matricaria recutita extracted by ultrasound was the highest radical scavenging ability. Conclusion: Result indicated both ultrasound and maceration extracts could increase the oil oxidative stability but could not increase compared to BHA. In most cases, the extract samples by ultrasound had a better effect on stabilizing of sunflower oil during frying.

Synthesis, Cytotoxicity and Antioxidant Activity of New Analogs of RC-121 Synthetic Derivatives of Somatostatin

2019 ◽  
Vol 18 (10) ◽  
pp. 1417-1424 ◽  
Author(s):  
Emilia Naydenova ◽  
Diana Wesselinova ◽  
Svetlana Staykova ◽  
Ivan Goshev ◽  
Ljubomir Vezenkov
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Capacity ◽  
Cell Line ◽  
Cancer Cell ◽  
Cancer Cell Line ◽  
Colorectal Cancer Cell Line ◽  
Cervical Cancer Cell Line ◽  
Synthetic Derivatives ◽  
Derivatives Of

Background: Based on the structure of RC-121 (D-Phe-c (Cys-Tyr-D-Trp-Lys-Val-Cys)-Thr-NH2, - synthetic derivatives of somatostatin), some analogs were synthesized and tested for in vitro cytotoxic and antioxidant activity. Objectives: The new analogs were modifyed at position 5 with Dap (diaminopropanoic acid), Dab (diaminobutanoic acid) and Orn and at position 6 with the unnatural amino acids Tle (t-leucine). Methods: The in vitro cytotoxic effects of the substances were investigated against a panel of human tumor cell lines HT-29 (Human Colorectal Cancer Cell Line), MDA-MB-23 (Human Breast Cancer Cell Line), Hep G-2 (Human Hepatocellular Carcinoma Cell Line) and HeLa (cervical cancer cell line). The antioxidant capacities were tested by ORAC (Oxygen Radical Antioxidant Capacity) and HORAC (Hydroxyl Radical Averting Capacity) methods. Results: All substances expressed significantly higher antioxidant capacity by comparison with galic acid and Trolox. All substances showed considerable antioxidant capacity as well. Compound 2T (D-Phe-c(Cys-Tyr-DTrp- Dap-Tle-Cys)-Thr-NH2)had the highest antioxidant effect. The compound 4T (D-Phe-c(Cys-Tyr-D-Trp- Orn-Tle-Cys)-Thr-NH2) displayed antiproliferative effect on HeLa cells with IC50 30 µM. The peptide analog 3T (D-Phe-c(Cys-Tyr-D-Trp-Lys-Tle-Cys)-Thr-NH2) exerted the most pronounced inhibition on the cell vitality up to 53%, 56% and 65% resp. against MDA-MB-23, Hep G-2, HeLa in the higher tested concentration. Conclusion: The somatostatin analogs showed moderate influence on the vitality of different tumor cells and could be used in changing their pathology.

The role of secondary alcoholic groups of D-galacturonan in its degradation with exo-D-galacturonanase

1980 ◽  
Vol 45 (2) ◽  
pp. 427-434 ◽  
Author(s):  
Kveta Heinrichová ◽  
Rudolf Kohn
Keyword(s):  
Acetyl Derivative ◽  
Competitive Inhibitor ◽  
Hydroxyl Groups ◽  
Pectic Acid ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
The Individual ◽  
Degradation Degree ◽  
Derivatives Of

The effect of exo-D-galacturonanase from carrot on O-acetyl derivatives of pectic acid of variousacetylation degree was studied. Substitution of hydroxyl groups at C(2) and C(3) of D-galactopyranuronic acid units influences the initial rate of degradation, degree of degradation and its maximum rate, the differences being found also in the time of limit degradations of the individual O-acetyl derivatives. Value of the apparent Michaelis constant increases with increase of substitution and value of Vmax changes. O-Acetyl derivatives act as a competitive inhibitor of degradation of D-galacturonan. The extent of the inhibition effect depends on the degree of substitution. The only product of enzymic reaction is D-galactopyranuronic acid, what indicates that no degradation of the terminal substituted unit of O-acetyl derivative of pectic acid takes place. Substitution of hydroxyl groups influences the affinity of the enzyme towards the modified substrate. The results let us presume that hydroxyl groups at C(2) and C(3) of galacturonic unit of pectic acid are essential for formation of the enzyme-substrate complex.

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.

scholarly journals A Novel Stoichio-Kinetic Model for the DPPH• Assay: The Importance of the Side Reaction and Application to Complex Mixtures

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1019
Author(s):  
Lucrezia Angeli ◽  
Sebastian Imperiale ◽  
Yubin Ding ◽  
Matteo Scampicchio ◽  
Ksenia Morozova
Keyword(s):  
Antioxidant Activity ◽  
Kinetic Model ◽  
Rate Constant ◽  
High Resolution Mass Spectrometry ◽  
Sinapic Acid ◽  
Side Reaction ◽  
Main Reaction ◽  
Dpph Assay ◽  
Best Fitting ◽  
The Common

The 2,2-diphenyl-1-picrylhydrazyl (DPPH•) assay is widely used to determine the antioxidant activity of food products and extracts. However, the common DPPH• protocol uses a two-point measurement and does not give information about the kinetics of the reaction. A novel stoichio-kinetic model applied in this study monitors the consumption of DPPH• by common antioxidants following the second order reaction. The fitting of such decay yields the rate constant k1, which describes the main reaction between antioxidants and DPPH•, and the rate constant k2, which is attributed to a slower side reaction considering the products generated between the transient radicals (AO•) and another molecule of DPPH•. The model was first applied to antioxidant standards. Sinapic acid, Trolox and ascorbic and chlorogenic acids did not show any side reaction. Instead gallic, ferulic and caffeic acids achieved the best fitting with k2. The products of the side reaction for these compounds were confirmed and identified with high-resolution mass spectrometry. Finally, the kinetic model was applied to evaluate the antioxidant activity of eight herbal extracts. This study suggests a new kinetic approach to standardize the common DPPH• assay for the determination of antioxidant activity.

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