scholarly journals The Substituent Effect on the Radical Scavenging Activity of Apigenin

Molecules ◽  
2018 ◽  
Vol 23 (8) ◽  
pp. 1989 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Da-Fu Chen ◽  
Geng Deng ◽  
Rui Guo
Keyword(s):  
Density Functional ◽  
Antioxidative Activity ◽  
Radical Scavenging Activity ◽  
Resonance Effect ◽  
Radical Scavenging ◽  
Free Radical Scavengers ◽  
Polar Phase ◽  
Natural Foods ◽  
Electron Donating Groups ◽  
The Relationship

Flavonoids widely found in natural foods are excellent free radical scavengers. The relationship between the substituent and antioxidative activity of flavonoids has not yet been completely elucidated. In this work, the antioxidative activity of apigenin derivatives with different substituents at the C3 position was determined by density functional theory (DFT) calculations. The bond dissociation enthalpy (BDE), ionization potential (IP), and proton affinity (PA) were calculated. Donator acceptor map (DAM) analysis illustrated that the studied compounds are worse electron acceptors than F and also are not better electron donors than Na. The strongest antioxidative group of apigenin derivatives was the same as apigenin. Excellent correlations were found between the BDE/IP/PA and Hammett sigma constants. Therefore, Hammett sigma constants can be used to predict the antioxidative activity of substituted apigenin and to design new antioxidants based on flavonoids. In non-polar phases, the antioxidative activity of apigenin was increased by the electron-withdrawing groups, while it was reduced by the electron-donating groups. Contrary results occurred in the polar phase. The electronic effect of the substituents on BDE(4′-OH), BDE(5-OH), PA(4′-OH), and IP is mainly controlled by the resonance effect, while that on BDE(7-OH), PA(5-OH), and PA(7-OH) is governed by the field/inductive effect.

scholarly journals DFT Studies on the Antioxidant Activity of Naringenin and Its Derivatives: Effects of the Substituents at C3

2019 ◽  
Vol 20 (6) ◽  
pp. 1450 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Geng Deng ◽  
Rui Guo ◽  
Da-Fu Chen ◽  
Zhong-Min Fu
Keyword(s):  
Antioxidant Activity ◽  
Density Functional ◽  
Radical Scavenging Activity ◽  
Resonance Effect ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Dft Method ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Selection Of

The radical scavenging activity of a flavonoid is largely influenced by its structure. The effects of the substituents at C3 position on the antioxidant activity of naringenin were carried out using the density functional theory (DFT) method. The reaction enthalpies related with the three well-established mechanisms were analyzed. Excellent correlations were found between the reaction enthalpies and Hammett sigma constants. Equations obtained from the linear regression can be helpful in the selection of suitable candidates for the synthesis of novel naringenin derivatives with enhanced antioxidant properties. In the gas and benzene phases, the antioxidant activity of naringenin was enhanced by the electron-donating substituents via weakening the bond dissociation enthalpy (BDE). In the water phase, it was strengthened by electron-withdrawing groups—via lowering the proton affinity (PA). The electronic effect of the substituent on the BDE of naringenin is mainly governed by the resonance effect, while that on the ionization potential (IP) and PA of naringenin is mainly controlled by the field/inductive effect.

scholarly journals Substituent Effects on the Radical Scavenging Activity of Isoflavonoid

2019 ◽  
Vol 20 (2) ◽  
pp. 397 ◽  
Author(s):  
Yan-Zhen Zheng ◽  
Geng Deng ◽  
Rui Guo ◽  
Da-Fu Chen ◽  
Zhong-Min Fu
Keyword(s):  
Electron Transfer ◽  
Density Functional ◽  
Antioxidative Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Substituent Effects ◽  
Hydrogen Atom Transfer ◽  
Electronic Effects ◽  
Antioxidative Properties ◽  
Electronic Effects Of Substituents

Understanding the role of substituents is of great importance for the preparation of novel phenolic compounds with enhanced antioxidative properties. In this work, the antioxidative activity of isoflavonoid derivatives with different substituents placed at the C2 position was determined by density functional theory (DFT) calculations. The bond dissociation enthalpy (BDE), ionization potential (IP), and proton affinity (PA) related to hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET) mechanisms were calculated. The strongest antioxidative group of isoflavonoid is not altered by the substituents. Excellent correlations were found between the BDE/IP/PA and Hammett sigma constants. Equations obtained from linear regression can be useful in the selection of suitable candidates for the synthesis of novel isoflavonoids derivatives with enhanced antioxidative properties. In the gas and benzene phases, the electron-donating substituents would enhance the antioxidative activity of isoflavonoids via weakening the BDE of 4′−OH. In water phase, they will reduce the antioxidative by strengthening the PA of 7−OH. Contrary results occur for the electron-withdrawing groups. In addition, the electronic effects of substituents on the BDE/IP/PA have also been analyzed.

scholarly journals Radical-Scavenging and UV-Radiation Absorption Activities of Aaptamine Derivatives: DFT and TD-DFT Studies

2021 ◽  
Author(s):  
Thi Hoai Nam Doan ◽  
Thi Le Anh Nguyen ◽  
Nguyen Thi Ai Nhung ◽  
Duong Tuan Quang ◽  
Duy Quang Dao
Keyword(s):  
Density Functional ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hydrogen Atom Transfer ◽  
Radiation Absorption ◽  
Functional Theory ◽  
Radical Adduct ◽  
Td Dft ◽  
Potential Applications

Antioxidant and UV absorption activities of three aaptamine derivatives including piperidine[3,2-b]demethyl(oxy)aaptamine (C1), 9-amino-2-ethoxy-8-methoxy-3H-benzo[de][1,6]naphthyridine-3-one (C2), and 2-(sec-butyl)-7,8-dimethoxybenzo[de]imidazo[4,5,1-ij][1,6]-naphthyridin-10(9H)-one (C3) were theoretically studied by density functional theory (DFT). Optimized geometries of C1C3 and theirs intrinsic thermochemical properties such as bond dissociation energy, proton affinity, and ionization potential were calculated at DFT/M05-2X/6-311++G(d,p) level of theory in vacuo and in water. The results show that C1C3 exhibited similar potent antioxidant activities, which are comparable to well-known antioxidants such as Trolox or cembrene. The radical scavenging activity of the antioxidants were then investigated by evaluation the Gibbs free energy (ΔrG0) of the reaction between C1C3 and the HOO●/HO● radicals via four mechanisms, including: hydrogen atom transfer (HAT), single electron transfer (SET), proton loss (PL) and radical adduct formation (RAF). Kinetic calculation reveals that HOO● scavenging in water is occurred via HAT mechanism with C1@C19 while RAF is more dominant with C2 and C3. Antioxidant activity of aaptamine derivatives can be classified as C1 > C3 > C2. In addition, all compounds are active in UV-Vis absorption; the excitations of which are determined as π-π* transition. Overall, the results suggest the potential applications of the aaptamines in pharmaceutics and cosmetics, i.e. as sunscreen and antioxidant ingredient<br>

scholarly journals Antioxidant Activity of Metabolites from Coleonema Album (Rutaceae)

2006 ◽  
Vol 1 (5) ◽  
pp. 1934578X0600100 ◽  
Author(s):  
Lindy L. Esterhuizen ◽  
Riaan Meyer ◽  
Ian A. Dubery
Keyword(s):  
Antioxidant Activity ◽  
South African ◽  
Structural Information ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Active Components ◽  
Bioassay Guided Fractionation ◽  
The Relationship

Coleonema album, a member of the South African ‘Fynbos’ biome, was evaluated for its antioxidant and free radical scavenging activity. Ethanol- and acetone-based extracts from plant material obtained from two different geographical areas were analysed. A bioassay-guided fractionation methodology was followed for screening of active compounds. The 1,1-diphenyl-2-picrylhydrazyl (DPPH)-TLC method revealed the presence of a number of antioxidants which were quantified by the DPPH-spectrophotometric assay and the oxygen radical absorbance capacity (ORAC) assay. The C. album extracts possessed significant in vitro antioxidant activity, a large portion of which appeared to be contributed by the phenolic compounds. In contrast, the reducing power of the extracts could not be correlated with the observed antioxidant activity. Identification and structural information of the active components were obtained by a combination of preparative TLC and LC-MS which revealed the presence of coumarin aglycones and glycosides. The results of this study indicate that C. album contains strong antioxidants that warrant further investigation into the relationship between the structure and activity of the active coumarin metabolites.

scholarly journals New 1,3,5-Triazine Derivatives Incorporating Aminobenzenesulfonamide, Aminoalcohol, Piperazine, Chalcone or Stilbene Structural Motifs and Evaluation of Their Antioxidative Activity

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 17
Author(s):  
Eva Havránková ◽  
Nikola Čalkovská ◽  
Tereza Padrtová ◽  
Jozef Csöllei ◽  
Radka Opatřilová ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Ascorbic Acid ◽  
Antioxidative Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Scavenging Activity ◽  
Inhibition Activity ◽  
Structural Motifs ◽  
Triazine Derivatives ◽  
Acidic Resin

A series of 1,3,5-triazine derivatives, incorporating aminobenzenesulfonamide, aminoalcohol/phenol, piperazine, chalcone, or stilbene structural motifs, were evaluated as potential antioxidants. The compounds were prepared by using step by step nucleophilic substitution of chlorine atoms in starting 2,4,6-trichloro-1,3,5-triazine. Reactions were catalyzed by Cu(I)-supported on a weakly acidic resin. The radical scavenging activity was determined in terms of %inhibition activity and IC50, using the ABTS method. Trolox and ascorbic acid (ASA) were used as standards. In the lowest used concentration 1 × 10−4 M, the %inhibition activity at time 0 min was comparable with both standards at least for 10 compounds. After 60 min compounds 1, 2, 9 and 25 showed nearly twice %inhibition (73.44–87.09%) in comparison with standards (Trolox = 41.49%; ASA = 31.07%). Values of IC50 correlated with %inhibition activity. For compounds 1, 2, 9 and 25 values of IC50 in time 60 min (17.16–27.78 μM) were 5 times lower than IC50 of both standards (Trolox = 178.33 μM; ASA = 147.47 μM). Based on these results, the presented 1,3,5-triazine derivatives and their analogs have a high potential in the treatment of illnesses caused or related to oxidative stress.

scholarly journals Antioxidant Activity and Acteoside Analysis of Abeliophyllum distichum

Antioxidants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1148 ◽  
Author(s):  
Hak-Dong Lee ◽  
Ji Hyun Kim ◽  
Qi Qi Pang ◽  
Pil-Mun Jung ◽  
Eun Ju Cho ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidative Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Nutritional Supplements ◽  
Scavenging Activity ◽  
Antioxidant Agent ◽  
Abeliophyllum Distichum ◽  
Potential Use

This study determined acteoside and its content in Abeliophyllum distichum via HPLC/UV and LC/ESI-MS to obtain insights into the potential use of this plant as an antioxidant agent. Moreover, 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl (•OH), and O2− radical scavenging activity assays were performed to assess in vitro antioxidative activity. The DPPH, •OH, and O2− radical scavenging activities of A. distichum leaf EtOH extracts at a 250 μg/mL concentration were 88.32%, 94.48%, and 14.36%, respectively, whereas those of stem extracts at the same concentration were 88.15%, 88.99%, and 15.36%, respectively. The contents of acteoside in A. distichum leaves and stems were 162.11 and 29.68 mg/g, respectively. Acteoside was identified as the main antioxidant compound in A. distichum leaves, which resulted in DPPH, •OH, and O2− radical scavenging activities of 82.84%, 89.46%, and 30.31%, respectively, at a 25 μg/mL concentration. These results indicate that A. distichum leaves and stems containing the antioxidant acteoside can be used as natural ingredients for functional and nutritional supplements.

Density Functional Theory Calculations of the Radical Scavenging Activity of Alkannin Derivatives

2012 ◽  
Vol 189 ◽  
pp. 225-231
Author(s):  
Xiang Peng Guo ◽  
Rui Fa Jin
Keyword(s):  
Density Functional ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Density Functional Theory Calculations ◽  
Hydrogen Atom Transfer ◽  
Scavenging Activity ◽  
Functional Theory ◽  
Hydrogen Bond Formation ◽  
Structural And Electronic Properties ◽  
The One

The structural and electronic properties of alkannin and its derivatives and their radicals were investigated at density functional level. It turned out that the presence of the dihydroxy functionality increases the radical stability through hydrogen bond formation. The hydrogen atom transfer for alkannin derivatives is difficult to occur compared with zero compound phenol. However, alkannin derivatives appear to be good candidates for the one-electron-transfer, particularly for alkannin derivatives with –OCOCH=CH(CH3)2 and –OCOCH2CH(CH3)2 groups. It suggests that 1–7 are expected to be the promising candidates for radical scavenging activity compounds because The ionization potential (IP) values of 1–7 are lower than that of the zero compound phenol.

Effect of Metal Ions (Cu2+/Fe2+) on the Antioxidant Activity of L-Ascorbic Acid-Glycine Model System

2011 ◽  
Vol 396-398 ◽  
pp. 28-31
Author(s):  
Cheng Yi Lei ◽  
Da Zhai Zhou ◽  
Rong Zhao ◽  
Qi Hui Deng ◽  
Ai Nong Yu ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Maillard Reaction ◽  
Antioxidative Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Model System ◽  
Model Systems ◽  
Scavenging Activity ◽  
Metal Concentrations

The influence of Cu2+, Fe2+ on the Maillard reaction were studied by heating L-ascorbic(ASA) and glycine (Gly) solutions adjusted to pH 5 at 120±2°C for 140 min in an oil bath. The presence of metals affected the intensity of browning and intermediate products, as monitored by absorbance at 420 nm and absorbance at 294 nm, sharply increased with the increase of metal concentrations applied (0.000M, 0.005M, 0.010M, 0.015M, 0.020M). Thereafter, slight increases were observed up to 0.020M. Antioxidative activity of all MRPs derived from ASA-Gly model systems sharply increased at 0.015M (P < 0.05) and slightly changes in activity were found with increasing metal concentrations up to 0.020M. Moreover, radical-scavenging activity correlated well with browning intensity and absorbance at 294 nm.

Antioxidative Activity and Functional Properties of Hydrolysates of Camellia Seed Meal Treated with Trypsin

2012 ◽  
Vol 554-556 ◽  
pp. 1174-1177 ◽  
Author(s):  
Ying Sun ◽  
Guo Qin Liu ◽  
Xin Qi Liu
Keyword(s):  
Functional Properties ◽  
Antioxidative Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Seed Meal ◽  
Degree Of Hydrolysis ◽  
Foaming Capacity ◽  
Ph Range ◽  
Water Holding ◽  
As Solubility

Antioxidative activity and functional properties of hydrolysates prepared from defatted camellia seed meal(DCSM), using trypsin, with a degree of hydrolysis(DH) of 21.69% were determined. At this DH, the hydrolysates show the highest hydroxyl and superoxide anion radical scavenging activity (over 69.15 % and 78.22%, respectively). The functionalities of hydrolysates such as solubility, water-holding capacity,emulsifying activity, foaming capacity and foaming stability are remarkably improved at all test pH range. These results indicate that the DCSM hydrolysised by trypsin to produce hydrolysates with desirable antioxidative activity and functional properties.

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