scholarly journals Redox Properties of 8-Quinolinol and Implications for its Mode of Action

2011 ◽  
Vol 6 (5) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Vladimir Chobot ◽  
Sigrid Drage ◽  
Franz Hadacek
Keyword(s):  
Antioxidant Activity ◽  
Cyclic Voltammetry ◽  
Complex Formation ◽  
Mode Of Action ◽  
Reactive Oxygen Species Generation ◽  
Reducing Power ◽  
Free Form ◽  
Cytotoxic Activities ◽  
Major Mode ◽  
Deoxyribose Degradation

8-Quinolinol (oxine, 8-hydroxyquinoline) is a simple aromatic alkaloid with allelopathic, antibacterial, antifungal, and cytotoxic activities. Generally, it is assumed that 8-quinolinol toxicity depends on transition metal chelation that negatively affects their availability for metalloenzymes in the cell or reactive oxygen species generation (ROS), which are formed following reduction of molecular oxygen by autoxidation of the redox active metal central atom of the 8-quinolinol complex. On the contrary, beneficial effects of 8-quinolinol and its derivatives in the medication of certain degenerative diseases are known. In this context, the activity of 8-quinolinol derivatives is attributed to their antioxidant activity following iron complex formation. To address this controversial issue, we explore the possible anti- or pro-oxidant effects of 8-quinolinol and its iron complexes in the deoxyribose degradation assay, by cyclic voltammetry and in a biological assay. The antibacterial effects of 8-quinolinol and its complex with iron were evaluated on Curtobacterium flaccumfacies and Paenibacillus amylolyticus. 8-Quinolinol showed strong antioxidant activity in the deoxyribose degradation assay. This activity may not depend exclusively on iron chelation, but probably more on the notable reducing properties of 8-quinolinol; it proved to be a more efficient antioxidant than the flavonoids catechin and quercetin. By contrast, 8-quinolinol showed no pro-oxidative effects in the deoxyribose degradation assay, both in free form and in complex with iron, as it may occur with redox cyclers. Cyclic voltammetry confirmed this too. 8-Quinolinol significantly inhibited bacterial growth and respiration. Idiosyncratically, its 50:1 mixture with iron(III) ions was less active compared with free 8-quinolinol; it even caused a U-shaped nonlinear hormetic effect on growth and failed to inhibit respiration as totally as the pure mixture; the respiration was even accelerated compared with the control as a result of lower stress. Our results support the notion that complex formation with either iron or other transition metals affects the reducing power of 8-quinolinol, but, in contrast to general assumptions, this study finds no support that complex formation with iron represents the major mode of action.

Antioxidant Properties of Deer Blood Hydrolysate and the Possible Mode of Action

2013 ◽  
Vol 634-638 ◽  
pp. 1435-1440 ◽  
Author(s):  
Shuai Wang ◽  
Li Cheng Zhong ◽  
Xue Chao Zhai ◽  
Dong Dong Yin ◽  
Xin Yu Wu
Keyword(s):  
Antioxidant Activity ◽  
Mode Of Action ◽  
Antioxidant Properties ◽  
Reducing Power ◽  
Thiobarbituric Acid ◽  
Degree Of Hydrolysis ◽  
Thiobarbituric Acid Reactive Substance ◽  
Hydrolysis Time ◽  
Reactive Substance ◽  
Tbars Values

Deer blood was hydrolyzed using Alcalase with hydrolysis time ranged form 0 to 6 h, and the degree of hydrolysis (DH) of protein hydrolysates increased with increasing hydrolysis time (P < 0.05). The reducing power, radicals scavenging activities and Cu2+-chelation ability of deer blood hydrolysate (DBH) significantly enhanced with increasing hydrolysis time (P < 0.05). The antioxidant activity of DBH, indicated by thiobarbituric acid-reactive substance (TBARS) values in a liposome-oxidizing system, increased with increasing DH (P < 0.05). The results indicated that antioxidant activity of DBH depended on hydrolysis time, and the hydrolyzed deer blood could be a potent food antioxidant.

Evaluation of Antioxidant Activity of Some Common Mosses

2008 ◽  
Vol 63 (7-8) ◽  
pp. 476-482 ◽  
Author(s):  
Vladimír Chobot ◽  
Lenka Kubicová ◽  
Samar Nabbout ◽  
Ludek Jahodář ◽  
Franz Hadacek
Keyword(s):  
Antioxidant Activity ◽  
Cyclic Voltammetry ◽  
Iron Chelation ◽  
Reducing Power ◽  
Total Content ◽  
Positive Control ◽  
Type Reaction ◽  
Ethanol Extracts ◽  
Ribose Degradation ◽  
Antioxidant Effects

The antioxidant activity of ethanol extracts of Atrichum undulatum, Polytrichum formosum (Polytrichaceae), Pleurozium schreberi (Entodontaceae) and Thuidium tamariscinum (Thuidiaceae) was evaluated by an electrochemical method (cyclic voltammetry) and standard photometric methods: Fe(III) to Fe(II) reducing power, nitric oxide scavenging (NO) assay and simulation of Fenton-type reaction by nonsite-specific (NSSOH) and site-specific (SSOH) hydroxyl radical-mediated 2-deoxy-d-ribose degradation inhibition. The total content of phenols was determined by the Folin-Ciocalteau reagent. All tested species showed antioxidant effects lower than the positive control, caffeic acid. The extracts of A. undulatum and P. formosum contained the highest content of phenols and were the most effective in Fe(III) to Fe(II) reducing power, cyclic voltammetry and SSOH assay. By contrast, only the extract of Pl. schreberi showed activity in the NSSOH assay. A. undulatum and T. tamariscinum extracts were the most active in the NO assay. The results suggest that the extracts of A. undulatum and P. formosum possess stronger antioxidant activity than those of Pl. scheberi and T. tamariscinum, but they affect the Fenton-type reaction mainly by iron chelation.

Antioxidant Activity, Phenolic Content and Hematoprotective Effects of Cleome arabica Polyphenolic Leaf Extract

2019 ◽  
Author(s):  
C. Tigrine ◽  
A. Kameli
Keyword(s):  
Antioxidant Activity ◽  
Biological Effects ◽  
Reducing Power ◽  
Hematological Toxicity ◽  
Protective Effects ◽  
Ferrous Ions ◽  
Polyphenolic Extract ◽  
Cleome Arabica

In this study a polyphenolic extract from Cleome arabica leaves (CALE) was investigated for its antioxidant activity in vitro using DPPH•, metal chelating and reducing power methods and for its protective effects against AraC-induced hematological toxicity in vivo using Balb C mice. Results indicated that CALE exhibited a strong and dose-dependent scavenging activity against the DPPH• free radical (IC50 = 4.88 μg/ml) and a high reducing power activity (EC50 = 4.85 μg/ml). Furthermore, it showed a good chelating effects against ferrous ions (IC50 = 377.75 μg/ml). The analysis of blood showed that subcutaneous injection of AraC (50 mg/kg) to mice during three consecutive days caused a significant myelosupression (P < 0.05). The combination of CALE and AraC protected blood cells from a veritable toxicity. Where, the number of the red cells, the amount of hemoglobin and the percentage of the hematocrite were significantly high. On the other hand, AraC cause an elevation of body temperature (39 °C) in mice. However, the temperature of the group treated with CALE and AraC remained normal and did not exceed 37.5 °C. The observed biological effects of CALE, in vitro as well as in vivo, could be due to the high polyphenol and flavonoid contents. In addition, the antioxidant activity of CALE suggested to be responsible for its hematoprotective effect.

Phenolic Imidazole Derivatives with Dual Antioxidant/Antifungal Activity: Synthesis and Structure-Activity Relationship

2019 ◽  
Vol 15 (4) ◽  
pp. 341-351 ◽  
Author(s):  
Ana P. Bettencourt ◽  
Marián Castro ◽  
João P. Silva ◽  
Francisco Fernandes ◽  
Olga P. Coutinho ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antifungal Activity ◽  
Organic Molecules ◽  
Inhibitory Concentration ◽  
Yeast Species ◽  
Dpph Radical ◽  
Dpph Assay ◽  
Gram Negative ◽  
Structure Activity ◽  
Deoxyribose Degradation

Background: Previous publications show that the addition of a phenolic antioxidant to an antifungal agent, considerably enhances the antifungal activity. Objective: Synthesis of novel compounds combining phenolic units with linear or cyclic nitrogencontaining organic molecules with antioxidant/antifungal activity using methodologies previously developed in the group. Methods: Several N- [1,2-dicyano-2- (arylidenamino) vinyl]-O-alkylformamidoximes 3 were synthesized and cyclized to 4,5-dicyano-N- (N´-alcoxyformimidoyl)-2-arylimidazoles 4 upon reflux in DMF, in the presence of manganese dioxide or to 6-cyano-8-arylpurines 5 when the reagent was refluxed in acetonitrile with an excess of triethylamine. These compounds were tested for their antioxidant activity by cyclic voltammetry, DPPH radical (DPPH•) assay and deoxyribose degradation assay. The minimum inhibitory concentration (MIC) of all compounds was evaluated against two yeast species, Saccharomyces cerevisiae and Candida albicans, and against bacteria Bacillus subtilis (Gram-positive) and Escherichia coli (Gram negative). Their cytotoxicity was evaluated in fibroblasts. Results: Among the synthetised compounds, five presented higher antioxidant activity than reference antioxidant Trolox and from these compounds, four presented antifungal activity without toxic effects in fibroblasts and bacteria. Conclusion: Four novel compounds presented dual antioxidant/antifungal activity at concentrations that are not toxic to bacteria and fibroblasts. The active molecules can be used as an inspiration for further studies in this area.

Investigation of Oral Subacute Toxicity and In-Vitro Antioxidant Activity of Standardized Methanolic Extract of Quercus serrata Leaves

2020 ◽  
Vol 16 ◽  
Author(s):  
Maibam Beebina Chanu ◽  
Biseshwori Thongam ◽  
Khumukcham Nongalleima ◽  
Hans Raj Bhat ◽  
Surajit Kumar Ghosh ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Antioxidant Activity ◽  
Biochemical Parameters ◽  
Methanolic Extract ◽  
Reducing Power ◽  
Quercus Serrata ◽  
Control Group ◽  
Blood Cell Count ◽  
Toxicological Profile

Background: Quercus serrata Murray leaves have been used traditionally in the treatment of diabetes, dysmenorrhoea, inflammation and urinary tract infection. So, far no study had been reported on the toxicological profile and antioxidant properties of the plant. Objective: The present study was aimed to investigate the in-vivo toxicological profile and in-vitro antioxidant activities of the methanolic extract of standardized Quercus serrata leaves. Methods: Per-oral sub-acute toxicity study was performed in rats using three dose levels (200, 400 and 800 mg/kg b.w.) of the extract for 28-days. Control group received gum acacia suspended in water. Bodyweight was measured weekly. Biochemical parameters were analysed using the serum, the blood-cell count was done using whole blood. Pathological changes were also checked in highly perfused tissues. Further, in-vitro reducing power assay, nitric oxide scavenging assay, DPPH free-radical scavenging assay were performed to check the antioxidant activity of the extract. Results: There were no significant alterations in the blood-cell count and biochemical parameters analysed in the treatment group when compared with the normal control. Histopathology study of liver, kidney, pancreas, heart and brain revealed normal cellular architecture in the treatment groups alike the control group animals. Quercus serrata also showed a significant reduction of DPPH with IC50 4.48±0.254 µg/mL, in-vitro reducing power activity with IC50121.65±0.320 µg/mL and nitric oxide scavenging activity IC50 106.43±0.338 µg/mL. Conclusion: The above study showed that standardized methanolic extract of Quercus serrata leaves was safe after subacute oral administration in rats and has good antioxidant potential.

Design and Synthesis of Novel Anti-inflammatory/Anti-ulcer Hybrid Molecules with Antioxidant Activity

2020 ◽  
Vol 16 ◽  
Author(s):  
Bhim Bahadur Chaudhari ◽  
Alka Bali ◽  
Ajitesh Balaini
Keyword(s):  
Antioxidant Activity ◽  
Oral Absorption ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Antioxidant Potential ◽  
Inflammatory Activity ◽  
In Vivo Models ◽  
Standard Drug ◽  
Hybrid Molecules ◽  
Anti Inflammatory

Background: NSAIDs are the most widely prescribed medications worldwide for their anti-inflammatory, antipyretic, and analgesic effects However, their chronic use can lead to several adverse drug events including GI toxicity. The selective COX-2 inhibitors developed as gastro-sparing NSAIDs also suffer from serious adverse effects which limit their efficacy. Objective: Local generation of reactive oxygen species is implicated in NSAID-mediated gastric ulceration and their combination with H2 antagonists like famotidine reduces the risk of ulcers. The objective of this work was to design and synthesize novel methanesulphonamido isoxazole derivatives by hybridizing the structural features of NSAIDs with those of antiulcer drugs (ranitidine, famotidine, etc.) to utilize a dual combination of anti-inflammatory activity and reducing (antioxidant) potential. Method: The designing process utilized three dimensional similarity studies and utilized an isoxazole core having a potential for anti-inflammatory as well as radical scavenging antioxidant activity. The compounds were assayed for their antiinflammatory activity in established in vivo models. The in vitro antioxidant activity was assessed in potassium ferricyanide reducing power (PFRAP) assay employing ascorbic acid as the standard drug. Results: Compounds (5, 6, 9 and 10) showed anti-inflammatory activity comparable to the standard drugs and were also found to be non-ulcerogenic at the test doses. Compounds 6-10 exhibited good antioxidant effect in the concentration range of 1.0-50.0 µmol/ml. The test compounds were also found to comply with the Lipinski rule suggesting good oral absorption. Conclusion: A new series of isoxazole based compounds is being reported with good anti-inflammatory activity coupled with antioxidant potential as gastro-sparing anti-inflammatory agents.

Curcumin-based antioxidant and glycohydrolase inhibitor compounds: Synthesis and in vitro appraisal of the dual activity against diabetes

2020 ◽  
Vol 16 ◽  
Author(s):  
Sajjad Esmaeili ◽  
Nazanin Ghobadi ◽  
Donya Nazari ◽  
Alireza Pourhossein ◽  
Hassan Rasouli ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Enzyme Inhibitor ◽  
Radical Scavenging Activity ◽  
Curcuma Longa ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Inhibitory Effect ◽  
Curcumin Derivatives ◽  
Reducing Power Assay

Background: Curcumin, as the substantial constituent of the turmeric plant (Curcuma longa), plays a significant role in the prevention of various diseases, including diabetes. It possesses ideal structure features as enzyme inhibitor, including a flexible backbone, hydrophobic nature, and several available hydrogen bond (H-bond) donors and acceptors. Objective: The present study aimed at synthesizing several novel curcumin derivatives and further evaluation of these compounds for possible antioxidant and anti-diabetic properties along with inhibitory effect against two carbohydrate-hydrolyzing enzymes, α-amylase and α-glucosidase, as these enzymes are therapeutic targets for attenuation of postprandial hyperglycemia. Methods: Therefore, curcumin-based pyrido[2,3-d]pyrimidine derivatives were synthesized and identified using an instrumental technique like NMR spectroscopy and then screened for antioxidant and enzyme inhibitory potential. Total antioxidant activity, reducing power assay and 1,1-diphenyl-2-picrylhydrazyl (DPPH• ) radical scavenging activity were done to appraisal the antioxidant potential of these compounds in vitro. Results: Compounds L6-L9 showed higher antioxidant activity while L4, L9, L12 and especially L8 exhibited the best selectivity index (lowest α-amylase/α-glucosidase inhibition ratio). Conclusion: These antioxidant inhibitors may be potential anti-diabetic drugs, not only to reduce glycemic index but also to limit the activity of the major reactive oxygen species (ROS) producing pathways.

Contribution of Major Polyphenols to the Antioxidant Profile and Cytotoxic Activity of Olive Leaves

2019 ◽  
Vol 19 (13) ◽  
pp. 1651-1657
Author(s):  
Zouhaier Bouallagui ◽  
Asma Mahmoudi ◽  
Amina Maalej ◽  
Fatma Hadrich ◽  
Hiroko Isoda ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Hepg2 Cells ◽  
Cytotoxic Activities ◽  
Phenolic Composition ◽  
Olive Leaves ◽  
Total Polyphenols ◽  
Cytotoxic Effects ◽  
Antioxidant Profile ◽  
Phytochemical Profile ◽  
Mcf 7

Aim: This study was designed to investigate the phytochemical profile and the cytotoxic activities of the eco-friendly extracts of olive leaves from Chemlali cultivar. Materials and Methods: The Phenolic composition of olive leaves extracts, the antioxidant activity and the cytotoxic effects against MCF-7 and HepG2 cells were determined. Results: Olive leaves extracts showed relevant total polyphenols contents. Oleuropein was the major detected phenolic compound reaching a concentration of 16.9 mg/ml. The antioxidant potential of the studied extracts varied from 23.7 to 46.5mM Trolox equivalents as revealed by DPPH and ABTS assays. Cytotoxicity experiments showed similar trends for both HepG2 and MCF-7 cells with the infusion extract being the most active. Conclusion: This study denotes that olive leaves may have great potential as endless bioresource of valuable bioactive compounds which may have a wide application.

scholarly journals New insights of phenolic compounds from optimized fruit extract of Ficus auriculata

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Shahinuzzaman ◽  
Parul Akhtar ◽  
N. Amin ◽  
Yunus Ahmed ◽  
Farah Hannan Anuar ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Bioactive Compounds ◽  
Total Phenolic Content ◽  
Phenolic Content ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Total Phenolic ◽  
Fruit Extract ◽  
Optimum Extraction

AbstractIn this study, the extraction conditions extracted maximize amounts of phenolic and bioactive compounds from the fruit extract of Ficus auriculata by using optimized response surface methodology. The antioxidant capacity was evaluated through the assay of radical scavenging ability on DPPH and ABTS as well as reducing power assays on total phenolic content (TPC). For the extraction purpose, the ultrasonic assisted extraction technique was employed. A second-order polynomial model satisfactorily fitted to the experimental findings concerning antioxidant activity (R2 = 0.968, P < 0.0001) and total phenolic content (R2 = 0.961, P < 0.0001), indicating a significant correlation between the experimental and expected value. The highest DPPH radical scavenging activity was achieved 85.20 ± 0.96% at the optimum extraction parameters of 52.5% ethanol (v/v), 40.0 °C temperature, and 22 min extraction time. Alternatively, the highest yield of total phenolic content was found 31.65 ± 0.94 mg GAE/g DF at the optimum extraction conditions. From the LC–ESI–MS profiling of the optimized extract, 18 bioactive compounds were tentatively identified, which may regulate the antioxidant activity of fruits of F. auriculata.

scholarly journals Physicochemical Properties and Biological Activity of Active Films Based on Corn Peptide Incorporated Carboxymethyl Chitosan

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 604
Author(s):  
Liyan Wang ◽  
Liang Lei ◽  
Kang Wan ◽  
Yuan Fu ◽  
Hewen Hu
Keyword(s):  
Antioxidant Activity ◽  
Physicochemical Properties ◽  
Food Packaging ◽  
Biological Activities ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Carboxymethyl Chitosan ◽  
Vapor Permeability ◽  
Zone Method ◽  
Oil Resistance

Active films based on carboxymethyl chitosan incorporated corn peptide were developed, and the effect of the concentration of corn peptide on films was evaluated. Physicochemical properties of the films, including thickness, opacity, moisture content, color, mechanical properties, water vapor permeability, and oil resistance, were measured. Biological activities of the films, including the antioxidant and antibacterial activities, were characterized in terms of 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging activity, reducing power, the total antioxidant activity, and the filter disc inhibition zone method. The results indicated that the incorporation of corn peptide caused interactions between carboxymethyl chitosan and corn peptide in Maillard reaction and gave rise to the films light yellow appearance. Compared with the Control, the degree of glycosylation, browning intensity, thickness, opacity, tensile strength, antioxidant activity, and antibacterial activity of films were increased, but the elongation, vapor permeability, and oil resistance of films were decreased. The films based on corn peptide and carboxymethyl chitosan can potentially be applied to food packaging.

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