Usnic Acid as a Potential Free Radical Scavenger and its Inhibitory Activity Toward SARS-CoV-2 Proteins

2021 ◽  
Vol 20 (06) ◽  
pp. 655-666
Author(s):  
Jelena Đorović Jovanović ◽  
Nedeljko Manojlović ◽  
Zoran Marković
Keyword(s):  
Free Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Usnic Acid ◽  
Hydrogen Atom Transfer ◽  
Free Radical Scavenging ◽  
Radical Scavenger ◽  
Radical Species ◽  
Free Radical Species ◽  
Antioxidative Action

The antioxidative activity and free radical scavenging potency of usnic acid towards eight selected free radical species are examined. The thermodynamic parameters in the absence of harmful free radicals are used to predict the most favorable mechanism of antioxidative action. The reaction enthalpies are used to define the most probable mechanism of free radical scavenging in the presence of free radical species. The obtained results indicate that the favorable mechanism of antiradical action is dependent both on the polarity of solvents and the nature of free radical species. From the achieved results, it is clear that Sequential Proton Loss Electron Transfer (SPLET) is the most probable for antioxidative action in water and methanol, while competition between SPLET and Hydrogen Atom Transfer (HAT) is presented in benzene. The free radical scavenging of eight free radical species under investigation is possible, and the most believable mechanism of action is SPLET, in all three investigated solvents. Since usnic acid exhibits significant radical scavenging activity that affects the maintenance of redox hemostasis, its inhibitory potency toward COVID-19 targeted proteins molecular docking study is performed. The obtained results indicate that usnic acid has the potential to inhibit the functional proteins of SARS-CoV-2.

scholarly journals Bergenin Content and Free Radical Scavenging Activity of Bergenia Extracts

2015 ◽  
Vol 10 (7) ◽  
pp. 1934578X1501000
Author(s):  
Helena Hendrychová ◽  
Jan Martin ◽  
Lenka Tůmová ◽  
Nina Kočevar-Glavač
Keyword(s):  
Free Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hplc Method ◽  
Free Radical Scavenging ◽  
Free Radical Scavenging Activity ◽  
Free Radical Scavengers ◽  
Radical Scavenger ◽  
Scavenging Activity ◽  
Different Seasons

Our research was focused on the evaluation of bergenin content and free radical scavenging activity of extracts prepared from three different species of Bergenia - B. crassifolia (L.) Fritsch., B. ciliata (Haw.) Sternb. and B. x ornata Stein. collected during different seasons. Using an HPLC method, the highest total amount of bergenin was revealed in the leaves of B. x ornata and B. crassifolia (4.9 - 5.1 mg.g−1). Free radical scavenging power was determined by two methods - FRAP and NADH. The best free radical scavengers were B. crassifolia (FRAP: 6.7 - 15.9 mg GAE.100g−1; NADH: 20.3 - 50.9%) and B. ornata (FRAP: 13.7 - 15.2 mg GAE.100g−1; NADH: 29.3 - 31.1%). The lowest content of bergenin and the weakest radical scavenger was B. ciliata (bergenin: 3.1 mg.g−1; FRAP: 5.5 - 11.0 mg GAE.100g−1; NADH: 23.2 - 25.6%). The presence of a large percentage of bergenin is responsible for the radical scavenging activity, as shown by the results from the FRAP and NADH assays. Significant, positive correlation was found between bergenin content and radical scavenging activity in both methods.

DPPH Free Radical Scavenger Components from the Fruits of Alpinia rafflesiana Wall. ex. Bak. (Zingiberaceae)

2004 ◽  
Vol 59 (11-12) ◽  
pp. 811-815 ◽  
Author(s):  
Habsah Mohamad ◽  
Faridah Abas ◽  
Dharma Permana ◽  
Nordin H. Lajis ◽  
Abdul Manaf Ali ◽  
...  
Keyword(s):  
Free Radical ◽  
Methanol Extract ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Scavenging Activity ◽  
Colorimetric Analysis ◽  
Natural Sources

The methanol extract of the dried ripe fruits of Alpinia rafflesiana was investigated for its DPPH free radical scavenger constituents. 2′,3′,4′,6′-Tetrahydroxychalcone (7), which has never been isolated from natural sources was found to be most active as a DPPH free radical scavenger with the IC50 value of 55 μᴍ. Other known compounds isolated from this species include 5,6-dehydrokawain (1), flavokawin B (2), 1,7-diphenyl-5-hydroxy-6-hepten-3-one (3), (-)-pinocembrin (4), cardamonin (5) and (-)-pinostrobin (6). The DPPH free radical scavenger compounds were detected using TLC autographic analysis. The percentage inhibition of DPPH free radical scavenging activity was measured on isolates (5-7) using colorimetric analysis.

Synthesis, antibacterial and free radical scavenging activity of some newer N-((10-nitro-1H-indolo [1, 2-c]quinazolin-12-yl)methylene)benzenamines

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
A. Dixit ◽  
D. Pathak ◽  
G.K. Sharma
Keyword(s):  
Free Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Free Radical Scavenging Activity ◽  
Diffusion Method ◽  
Radical Scavenger ◽  
Scavenging Activity ◽  
Dpph Method ◽  
Antibacterial Potential

AbstractPresent research is oriented on the synthesis of some novel 12-(N-arylmethaniminyl)indolo[1,2-c]quinazoline analogs (4b1-4b11) and their characterization by 1H NMR, 13C NMR, FTIR and mass spectrophotometry. Their free radical scavenging activity and antibacterial potential were also evaluated. Many derivatives have shown a marked free radical scavenging capacity in all the concentrations but specifically compounds 4b7, 4b8 and 4b11 have shown good antioxidant potential with an IC50 value of 25.18 μmol/L, 28.09 μmol/L ---amp--- 44.22 μmol/L, respectively (DPPH method) and 39.46 μmol/L, 44.47 μmol/L ---amp--- 35.61 μmol/L, respectively (H2O2 method). The antibacterial evaluation was carried out against B. subtilis and E. coli by agar well diffusion method and it revealed that all the compounds in the series were having marked antibacterial activity but compounds 4b9 and 4b11 have shown best antibacterial potential. Then, it was concluded that the derivatives which were containing substituted anilines (4-Nitro, 4-Fluoro, 4-Bromo ---amp--- 4-Chloro-2-nitro) on the carbon attached on the 12th position of indoloquinazoline moiety were having marked potential as an antibacterial and free radical scavenger.

Anti-inflammatory and Radical Scavenge Effects of Arctium lappa

1996 ◽  
Vol 24 (02) ◽  
pp. 127-137 ◽  
Author(s):  
Chun-Ching Lin ◽  
Jer-Min Lin ◽  
Jeng-Jer Yang ◽  
Shu-Chuan Chuang ◽  
Takashi Ujiie
Keyword(s):  
Free Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Free Radical Scavenging ◽  
Radical Scavenger ◽  
Scavenging Activity ◽  
Paw Edema ◽  
Arctium Lappa ◽  
Radical Scavenger Activity ◽  
Scavenger Activity

The effects of Arctium lappa L. (root) on anti-inflammatory and free radical scavenger activity were investigated. Subcutaneous administration of A. lappa crude extract significantly decreased carrageenan-induced rat paw edema. When simultaneously treated with CCl4, it produced pronounced activities against CCl4-induced acute liver damage. The free radical scavenging activity of its crude extract was also examined by means of an electron spin resonance (ESR) spectrometer. The IC50 of A. lappa extract on superoxide and hydroxyl radical scavenger activity was 2.06 mg/m 11.8 mg/m1, respectively. These findings suggest that Arctium lappa possess free radical scavenging activity. The inhibitory effects on carrageenan-induced paw edema and CCl4-induced hepatotoxicity could be due to the scavenging effect of A. lappa.

scholarly journals Free Radical Scavenging Potency of Dihydroxybenzoic Acids

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Dejan Milenković ◽  
Jelena Đorović ◽  
Svetlana Jeremić ◽  
Jasmina M. Dimitrić Marković ◽  
Edina H. Avdović ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Free Radical ◽  
Density Functional ◽  
Reaction Pathway ◽  
Radical Scavenging ◽  
Theoretical Models ◽  
Hydrogen Atom Transfer ◽  
Free Radical Scavenging ◽  
Thermodynamic Quantities ◽  
Antioxidative Action

In order to evaluate the free radical scavenging potency of dihydroxybenzoic acids (DHBAs) the Density Functional Theory (DFT) was used. The M05-2X/6-311++G(d,p) and B3LYP-D2/6-311++G(d,p) theoretical models were applied. Three possible antioxidant mechanisms were examined: hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms. All of these mechanisms have been studied in nonpolar (benzene and pentylethanoate) and polar solvents (water) using an implicit solvation model (SMD). The following thermodynamic quantities related to these mechanisms were calculated: bond dissociation enthalpy (BDE), ionization potential (IP), and proton affinity (PA). The obtained results indicated the HAT mechanism as the most favourable reaction pathway for antioxidative action of DHBAs in benzene. On the other hand, SPLET is indicated as predominant reaction mechanism in polar solvent. The SET-PT mechanism was not favourable reaction path for antioxidative action in any of the solvents under investigation.

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