Free radical scavenging and antioxidant properties of conducting polymers examined using EPR and NMR spectroscopies

2005 ◽  
Vol 153 (1-3) ◽  
pp. 153-156 ◽  
Author(s):  
P.A. Kilmartin ◽  
M. Gizdavic-Nikolaidis ◽  
Z. Zujovic ◽  
J. Travas-Sejdic ◽  
G.A. Bowmaker ◽  
...  
Keyword(s):  
Free Radical ◽  
Conducting Polymers ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Free Radical Scavenging

Flavones and Their Analogues as Bioactive Compounds – An Overview

2019 ◽  
Vol 16 (4) ◽  
pp. 377-391 ◽  
Author(s):  
B.S. Jayashree ◽  
H. Venkatachalam ◽  
Sanchari Basu Mallik
Keyword(s):  
Biological Activity ◽  
Free Radical ◽  
Bioactive Compounds ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Cost Effective ◽  
Free Radical Scavenging ◽  
Polyphenolic Compounds ◽  
Pharmacological Activities ◽  
Poor Solubility

Flavonoids constitute a large group of polyphenolic compounds that are known to have antioxidant properties, through their free radical scavenging abilities. They possess a chromone (γ- benzopyrone) moiety, responsible for eliciting many pharmacological activities. Even though, natural flavonoids are highly potent, owing to their poor solubility, they are less used. Therefore, attempts have been made to improve their stability, solubility, efficacy and kinetics by introducing various substituents on the flavone ring. For nearly the last two decades, flavones were synthesized in our laboratory by simple, convenient and cost-effective methods, with the knowledge of both synthetic and semi-synthetic chemistry. In this direction, it was considered worthwhile to present an overview on the synthesized flavonoids. This review creates a platform for highlighting various modifications done on the flavone system along with their biological activity.

scholarly journals Antioxidant and antimicrobial activities against Enterobacter cloacae of extracts of Eclipta alba Hassk.

2016 ◽  
Vol 19 (4) ◽  
pp. 76-83
Author(s):  
Trang Thi Xuan Dai ◽  
Anh Thi Tu Vo
Keyword(s):  
Free Radical ◽  
Vitamin C ◽  
Ethyl Acetate ◽  
Ethyl Acetate Extract ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Enterobacter Cloacae ◽  
Free Radical Scavenging ◽  
Antioxidant Vitamin ◽  
Eclipta Alba

This study was subjected to investigate antimicrobial and antioxidant properties of Eclipta alba extracts (methanol, hexane, chloroform and ethyl acetate extracts). The antioxidant property of the extract was assessed by 2,2- diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method. Kirby-Bauer method was used to determine the antibacterial activity against Enterobacter cloacae of the extracts. The extracts of Eclipta alba were tested against E. cloacae. The highest antibacterial potentiality was exhibited by the ethyl acetate extract of E. alba leaves, means of zones of bacterial growth inhibition are 26.3 mm at a concentration of 32 μg/mL. DPPH free radical scavenging effect of the extracts was compared with standard antioxidant vitamin C. The highest antioxidant activity was exhibited by the ethyl acetate extract of E. alba leaves. The result also showed that the DPPH scavenging activity of ethyl acetate extract from leaves of E. alba was high (EC50 = 419.38 μg/mL). However, this result was 18.99 times lower than that of vitamin C (EC50 = 22.08 μg/mL).

scholarly journals The Free Radical Scavenging and Anti-Isolated Human LDL Oxidation Activities of Pluchea indica (L.) Less. Tea Compared to Green Tea (Camellia sinensis)

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Kittipot Sirichaiwetchakoon ◽  
Gordon Matthew Lowe ◽  
Griangsak Eumkeb
Keyword(s):  
Free Radical ◽  
Green Tea ◽  
Camellia Sinensis ◽  
Hypochlorous Acid ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Ldl Oxidation ◽  
Caffeoylquinic Acid ◽  
Dicaffeoylquinic Acid

Tea is one of the most popular beverages in the world. Camellia sinensis tea (CST) or green tea is widely regarded as a potent antioxidant. In Thailand, Pluchea indica (L.) Less. tea (PIT) has been commercially available as a health-promoting drink. This study focused on free radical scavenging activities of PIT, and its ability to protect isolated human low-density lipoproteins (LDL) from oxidation by chemical agents. A preliminary study to investigate the antioxidant nature of PIT was undertaken. These included common antioxidant assays involving 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), hypochlorous acid (HOCl), and its potential to scavenge peroxynitrite. In separated experiments, isolated human LDL was challenged with either 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH), copper (Cu2+), or 3-Morpholinosydnonimine hydrochloride (SIN-1) to induce LDL oxidation. PIT exhibited antioxidant activity in all test systems and performed significantly better than CST in both DPPH (P<0.05; IC50PIT=245.85±15.83 and CST=315.41±24.18 μg/ml) and peroxynitrite scavenging assays. PIT at 75 μg/ml almost fully prevented the peroxynitrite over a 5 h period. Moreover, it displayed similar properties to CST during the antioxidation of isolated human LDL using AAPH, Cu2+, SIN-1, and hypochlorous acid scavenging assays. However, it revealed a significantly lower ABTS scavenging activity than CST (P<0.05; IC50PIT=30.47±2.20 and CST=21.59±0.67 μg/ml). The main constituents of the PIT were identified using LC-MS/MS. It contained 4-O-caffeoylquinic acid (4-CQ), 5-O-caffeoylquinic acid (5-CQ), 3,4-O-dicaffeoylquinic acid (3,4-CQ), 3,5-O-dicaffeoylquinic acid (3,5-CQ), and 4,5-O-dicaffeoylquinic acid (4,5-CQ). In conclusion, caffeoyl derivatives in PIT could play an important role in potent antioxidant properties. So, it may be further developed to be antioxidant beverages for preventing atherosclerosis and cardiovascular diseases associated with oxidative stress.

scholarly journals Domestic Cooking Effects of Bambara Groundnuts and Common Beans in the Antioxidant Properties and Polyphenol Profiles

2017 ◽  
Vol 6 (2) ◽  
pp. 24 ◽  
Author(s):  
V. Nyau ◽  
S. Prakash ◽  
J. Rodrigues ◽  
J. Farrant
Keyword(s):  
Free Radical ◽  
Methanolic Extract ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Esi Ms ◽  
Positive Effects ◽  
Phytochemical Profiles

Processing of legumes before consumption has several effects on micronutrients, macronutrients and phytonutrients. This study was undertaken to investigate the effect of domestic processing on antioxidant activities and phenolic phytochemicals of the red bambara groundnuts and red beans. The study employed in vitro antioxidant assays (DPPH and FRAP) to screen for antioxidant properties, HPLC-PDA-ESI-MS and Folin Ciocalteu assay to screen for phenolic phytochemical profiles. Domestic cooking displayed positive effects on the antioxidant activity and phenolic phytochemical profiles of the two legumes. The free radical scavenging speed increased 10-fold in the methanolic extract from cooked red bambara groundnuts compared to uncooked. By contrast, the free radical scavenging speed increased 20-fold in the methanolic extract from cooked red beans compared to uncooked. HPLC-PDA-ESI-MS profiles of the cooked red bambara groundnuts and red beans revealed a number of emergent phenolic compounds, mainly flavonoids. These data indicate that cooking appear to enhance the nutraceutical profiles of the legumes investigated.

Allopurinol does not enhance antioxidant properties of extracellular fluid

1988 ◽  
Vol 255 (1) ◽  
pp. H202-H206 ◽  
Author(s):  
B. J. Zimmerman ◽  
D. A. Parks ◽  
M. B. Grisham ◽  
D. N. Granger
Keyword(s):  
Free Radical ◽  
Xanthine Oxidase ◽  
Hypochlorous Acid ◽  
Ischemia Reperfusion ◽  
Parenchymal Cell ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Extracellular Fluid ◽  
Free Radical Scavenging ◽  
Beneficial Effects

Allopurinol has been shown to provide significant protection against ischemia/reperfusion-induced microvascular and parenchymal cell injury. It has been hypothesized that the protection seen with allopurinol after ischemia/reperfusion (I/R) is caused by inhibition of xanthine oxidase. However, recent reports suggest that the beneficial effects of allopurinol in I/R may be caused by direct free radical scavenging. The objective of this study was to determine whether the regimen of allopurinol administration used in most I/R studies leads to a significant modification of the free radical scavenging properties of extracellular fluid (ECF), i.e., plasma and lymph. Plasma and intestinal lymph samples obtained from both control and allopurinol-treated cats were used to assess the following: 1) allopurinol and oxypurinol concentrations, 2) xanthine oxidase inhibition, 3) myoglobin-catalyzed linolenic acid peroxidation, 4) hypochlorous acid scavenging, and 5) protein and nonprotein sulfhydryl content. ECF from allopurinol-treated animals contained approximately 10 microM each of allopurinol and oxypurinol. Ten percent ECF resulted in 80% inhibition of xanthine oxidase activity. Comparable volumes of control ECF did not inhibit xanthine oxidase. Furthermore, allopurinol treatment did not enhance the antioxidant properties of ECF. The results of this study do not support the contention that the beneficial effects of allopurinol in I/R injury are caused by the scavenging of oxidants produced in ECF by activated granulocytes.

scholarly journals Antioxidant Properties of the Leaves of Chromolaena odorata Linn

2013 ◽  
Vol 35 (1) ◽  
pp. 53-57
Author(s):  
D Bhargava ◽  
CK Mondal ◽  
JN Shivapuri ◽  
S Mondal ◽  
S Kar
Keyword(s):  
Nitric Oxide ◽  
Antioxidant Activity ◽  
Free Radical ◽  
Hydroxyl Radical ◽  
Methanolic Extract ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Rational Approach ◽  
Chromolaena Odorata

 Introduction: Chromolaena odorata Linn (Asteraceae) locally known as “Banmara” has the reputation of being used as a medicinal herb in Nepal. A systemic search for drug research in now considered to be a rational approach. Therefore in the present study an effort has been made to evaluate the antioxidant activity of the leaves of the above mentioned plant. Methods: In the present research work the ethanolic and methanolic extract of leaves of the plant C. odorata Linn was assessed for free radical scavenging and antioxidant activity. In this work the ability of the extract to scavenge nitric oxide, hydroxyl radical and 1,1-diphenyl-2- picrylhydrazyl (DPPH) were used to assess its free radical scavenging potentials. Results: The DPPH radical inhibition (%) was 59.10, 52.13 and 81.12 for ethanolic extract, methanolic extract and ascorbic acid respectively. Similarly ethanolic and methanolic extract  also showed significant free radical scavenging action against nitric oxide and hydroxyl radical. Conclusion: Against the backdrop of many known medicinal properties of this plant its ethanolic and methanolic extract of leaves reveals significant antioxidant properties. DOI: http://dx.doi.org/10.2126/joim.v35i1.8900   Journal of Institute of Medicine, April, 2013; 35:53-57

Heterogeneous Method for Grafting of Syringaldehyde onto Chitosan by Laccase Oxidation

2013 ◽  
Vol 477-478 ◽  
pp. 1340-1344
Author(s):  
Cheng Hua Yu ◽  
Ji Cheng Pei ◽  
Fang Dong Zhang
Keyword(s):  
Free Radical ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Free Radical Scavenging ◽  
Free Radical Scavenging Activity ◽  
Scavenging Activity ◽  
Amino Groups

Heterogeneous method for grafting of syringaldehyde (SD) onto chitosan by laccase oxidation, yielding a product with improved antioxidant activities. The results showed that about 1.1% amino groups participated in this reaction. The FTIR showed that the absorption of amino groups were decreased, the absorption of benzene ring structures were disappeared and a new band appeared at 1637 cm-1 corresponding to C=N vibrations that were due to the Schiff base reaction between the chitosan and syringaldehyde. Additionally, the chitosan had insignificant reducing power and DPPH free radical scavenging activity, SD-chitosan had reducing power of A700=0.684, DPPH free radical scavenging activity of 53.2%. SD-chitosan presented improved antioxidant properties.

scholarly journals FREE RADICAL SCAVENGING ACTIVITY OF MARINE SPONGES COLLECTED FROM KOVALAM, CHENNAI

2017 ◽  
Vol 10 (6) ◽  
pp. 321 ◽  
Author(s):  
Yuvarani Thambidurai ◽  
Sudarsanam D ◽  
Habeeb Skm ◽  
Ashok Kumar T
Keyword(s):  
Free Radical ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Marine Sponges ◽  
Free Radical Scavenging Activity ◽  
Scavenging Activity ◽  
Frap Assay ◽  
Antioxidant Power

Objective: The main focus of this study is to screen the marine sponges for potent free radical scavenging activity. Methods: Various methods such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assay are employed to ascertain the antioxidant properties of marine sponges namely Dysidea herbacea and Sigmadocia pumila. Results: On analyzing, the result of ABTS assay D. herbacea and S. pumila exhibited almost equal antioxidant properties. While calculating the inhibitory concentration 50% value for DPPH assay, the Sample 1 and 2 has an IC of 655.49 and 826.739 μl, respectively, and in FRAP assay, the Sample 1 and 2 has an IC of 67.587 and 74.57 μg, respectively. Conclusion: Overall from this assay, D. herbacea revealed slightly better antioxidant activity when compared to S. pumila, also which in future may serve as a better source to fight against various diseases

Comparison of Antioxidant Effects of the Proton Pump-Inhibiting Drugs Omeprazole, Esomeprazole, Lansoprazole, Pantoprazole, and Rabeprazole

Pharmacology ◽  
2020 ◽  
Vol 105 (11-12) ◽  
pp. 645-651 ◽  
Author(s):  
Mohammed N. Abed ◽  
Fawaz A. Alassaf ◽  
Mahmood H.M. Jasim ◽  
Mohanad Alfahad ◽  
Mohannad E. Qazzaz
Keyword(s):  
Free Radical ◽  
Proton Pump ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Acid Suppression ◽  
Free Radical Scavenging Activity ◽  
Scavenging Activity ◽  
Stable Free Radical

<b><i>Introduction:</i></b> Peptic lesions usually develop when there is an imbalance between aggressive drivers and gastro-protective mediators that guard the lining of the gastrointestinal tract. The most crucial of these mediators are antioxidants, whose loss may predispose to oxidative stress, which is believed to be the main aggravator of several diseases including peptic ulcer. Proton pump inhibitors (PPIs) are drugs that are highly effective and widely used for therapeutic management of peptic disorders through inhibition of gastric acid secretion. In spite of this, oxidative damage may continue to be a major issue that can predispose to future lesions. <b><i>Objective:</i></b> The present study is designed to explore the possible antioxidant capability of different PPIs, including omeprazole, esomeprazole, lansoprazole, pantoprazole, and rabeprazole, in an aim to suggest an agent that, in addition to its acid-suppression properties, can provide antioxidant profit. <b><i>Methods:</i></b> The antioxidant activity of different PPIs was evaluated calorimetrically to test the ability of each drug to quench oxygen free radical, using the well-known stable free radical α,α-diphenyl-β-picrylhydrazyl (DPPH), and compared to ascorbic acid (AA; vitamin C). The measurements were performed using a spectrophotometer at 517 nm. <b><i>Results:</i></b> All the studied drugs reduced DPPH, but to different extents. However, omeprazole and esomeprazole showed the highest ability to scavenge free radicals (50% inhibitory concentrations [IC<sub>50</sub>s] of the percentage for free radical scavenging activity are 18.7 ± 5.7 and 18.7 ± 5.7, respectively, and the AA equivalents are 83,772 ± 11,887 and 81,732 ± 8,523 mg AA/100 g, respectively). Conversely, lansoprazole, pantoprazole, and rabeprazole might be having no role in this story (IC<sub>50</sub>s of the percentage for free radical scavenging activity are 49.3 ± 3.1, 49 ± 9.4, and 40.7 ± 7.2, respectively, and the AA equivalents are 30,458 ± 3,884, 32,222 ± 10,377, and 37,876 ± 8,816 mg AA/100 g, respectively). <b><i>Conclusion:</i></b> Thus, omeprazole and esomeprazole may confer a significant dual action in gastrointestinal protection by providing potent antioxidant properties in addition to their major role as acid-suppression agents. However, further studies are essential to elucidate the mechanism behind the difference between the drugs of the same class.

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