Quercetin dual interaction at the membrane level

2019 ◽  
Vol 55 (12) ◽  
pp. 1750-1753 ◽  
Author(s):  
António de Granada-Flor ◽  
Carla Sousa ◽  
Hugo A. L. Filipe ◽  
M. Soledade C. S. Santos ◽  
Rodrigo F. M. de Almeida
Keyword(s):  
Antioxidant Activity ◽  
Mode Of Action ◽  
Membrane Domains ◽  
Regulatory Effect ◽  
Membrane Level

The (de)regulatory effect of quercetin in cholesterol-enriched membrane domains, beyond its antioxidant activity, emerges as an important mode of action.

scholarly journals Antioxidant Compounds from Microalgae: A Review

Marine Drugs ◽  
2021 ◽  
Vol 19 (10) ◽  
pp. 549
Author(s):  
Noémie Coulombier ◽  
Thierry Jauffrais ◽  
Nicolas Lebouvier
Keyword(s):  
Antioxidant Activity ◽  
Natural Products ◽  
Mode Of Action ◽  
Natural Antioxidants ◽  
Culture Conditions ◽  
Antioxidant Compounds ◽  
Oxygen Species ◽  
Synthetic Antioxidants ◽  
Metabolic Plasticity ◽  
The Right

The demand for natural products isolated from microalgae has increased over the last decade and has drawn the attention from the food, cosmetic and nutraceutical industries. Among these natural products, the demand for natural antioxidants as an alternative to synthetic antioxidants has increased. In addition, microalgae combine several advantages for the development of biotechnological applications: high biodiversity, photosynthetic yield, growth, productivity and a metabolic plasticity that can be orientated using culture conditions. Regarding the wide diversity of antioxidant compounds and mode of action combined with the diversity of reactive oxygen species (ROS), this review covers a brief presentation of antioxidant molecules with their role and mode of action, to summarize and evaluate common and recent assays used to assess antioxidant activity of microalgae. The aim is to improve our ability to choose the right assay to assess microalgae antioxidant activity regarding the antioxidant molecules studied.

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.

In vitro and in vivo determination of antioxidant activity and mode of action of isoquercitrin and Hyptis fasciculata

Phytomedicine ◽  
2009 ◽  
Vol 16 (8) ◽  
pp. 761-767 ◽  
Author(s):  
C.G. Silva ◽  
R.J. Raulino ◽  
D.M. Cerqueira ◽  
S.C. Mannarino ◽  
M.D. Pereira ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Mode Of Action

scholarly journals Mode of action and determination of antioxidant activity in the dietary sources: An overview

2020 ◽  
Author(s):  
Azhari Siddeeg ◽  
Nora M. AlKehayez ◽  
Hind A. Abu-Hiamed ◽  
Ekram A. Al-Sanea ◽  
Ammar M. AL-Farga
Keyword(s):  
Antioxidant Activity ◽  
Mode Of Action

scholarly journals ASSESSMENT OF ANTIMICROBIAL AND ANTIOXIDANT ACTIVITIES OF A SPECIES OF ASPERGILLUS: AN ENDOPHYTIC FUNGUS OF SCHIMA WALLICHII (DC.) KORTH. LEAVES

2017 ◽  
Vol 10 (9) ◽  
pp. 361
Author(s):  
Sunrit Basu Sarbadhikary ◽  
Narayan Chandra Mandal
Keyword(s):  
Antioxidant Activity ◽  
Ethyl Acetate ◽  
Mode Of Action ◽  
Pathogenic Bacteria ◽  
Ethyl Acetate Extract ◽  
Antioxidant Activities ◽  
Pathogenic Fungi ◽  
Structural Features ◽  
Fungal Endophyte ◽  
Schima Wallichii

  Objective: The main goals of this study were to check the antimicrobial and antioxidant potentials of an endophytic fungal strain isolated from the leaves of Schima wallichii (DC.) Korth.Methods: The antibacterial and antifungal activities of the isolated fungal endophyte Visva-Bharati endophyte fungal (VBEF2) were checked by disc diffusion and agar well diffusion methods, respectively, against six pathogenic bacteria and four pathogenic fungi. The minimum inhibitory concentration (MIC) values and the mode of action of VBEF2 against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli were determined following colony-forming units (CFU) counting method. Antioxidant activity of the isolate was studied following 2, 2-diphenyl-2- picrilhydrazyl (DPPH) reduction assay.Results: The cell-free supernatants (CFS) of VBEF2 exhibited excellent antibacterial activity against all the bacteria used. The ethyl acetate extract of the endophyte was found to have the MIC of 50 μg/ml and 150 μg/ml against S. aureus and E. coli, respectively. It showed bactericidal mode of action against both of them. The CFS of the strain VBEF2 also showed excellent activities against two animal and two plant pathogenic fungi by producing zones of inhibition in the range of 10-20 mm. In the DPPH scavenging antioxidant assay, the ethyl acetate extract of VBEF2 was found with a low IC50 value of 19.01 μg/ml. The strain VBEF2 was identified as a species of Aspergillus based on its colony morphology and structural features observed under a compound light microscope.Conclusion: The strain VBEF2 can be implemented in various fields of pharmaceutical industry as it showed multidimensional beneficial attributes such as excellent antimicrobial and antioxidant activity.

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