scholarly journals Computational Study of Ortho-Substituent Effects on Antioxidant Activities of Phenolic Dendritic Antioxidants

Antioxidants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 189 ◽  
Author(s):  
Choon Young Lee ◽  
Ajit Sharma ◽  
Julius Semenya ◽  
Charles Anamoah ◽  
Kelli N. Chapman ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Electron Transfer ◽  
Antioxidant Activities ◽  
Computational Study ◽  
Radical Scavenging ◽  
Substituent Effects ◽  
Phenolic Antioxidants ◽  
Electronic Effects ◽  
Total Enthalpy ◽  
Structure Activity

Antioxidants are an important component of our ability to combat free radicals, an excess of which leads to oxidative stress that is related to aging and numerous human diseases. Oxidative damage also shortens the shelf-life of foods and other commodities. Understanding the structure–activity relationship of antioxidants and their mechanisms of action is important for designing more potent antioxidants for potential use as therapeutic agents as well as preservatives. We report the first computational study on the electronic effects of ortho-substituents in dendritic tri-phenolic antioxidants, comprising a common phenol moiety and two other phenol units with electron-donating or electron-withdrawing substituents. Among the three proposed antioxidant mechanisms, sequential proton loss electron transfer (SPLET) was found to be the preferred mechanism in methanol for the dendritic antioxidants based on calculations using Gaussian 16. We then computed the total enthalpy values by cumulatively running SPLET for all three rings to estimate electronic effects of substituents on overall antioxidant activity of each dendritic antioxidant and establish their structure–activity relationships. Our results show that the electron-donating o-OCH3 group has a beneficial effect while the electron-withdrawing o-NO2 group has a negative effect on the antioxidant activity of the dendritic antioxidant. The o-Br and o-Cl groups did not show any appreciable effects. These results indicate that electron-donating groups such as o-methoxy are useful for designing potent dendritic antioxidants while the nitro and halogens do not add value to the radical scavenging antioxidant activity. We also found that the half-maximal inhibitory concentration (IC50) values of 2,2-diphenyl-1-picrylhydrazyl (DPPH) better correlate with the second step (electron transfer enthalpy, ETE) than the first step (proton affinity, PA) of the SPLET mechanism, implying that ETE is the better measure for estimating overall radical scavenging antioxidant activities.

scholarly journals Antioxidant and Chemosensitizing Effects of Flavonoids with Hydroxy and/or Methoxy Groups and Structure-Activity Relationship

2007 ◽  
Vol 10 (4) ◽  
pp. 537 ◽  
Author(s):  
Ju-Mi Jeong ◽  
Cheol-Hee Choi ◽  
Su-Kyeong Kang ◽  
In-Hwa Lee ◽  
Ji-Yoon Lee ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Oh Groups ◽  
Structure Activity ◽  
P Glycoprotein ◽  
Ic50 Values

Purpose. Flavonoids have been used as antioxidant, chemopreventive and chemosensitizing agents. In this study, eleven flavonoids containing a variety of hydroxy (OH) and/or methoxy (OMe) groups were evaluated for their antioxidant, cytotoxic and chemosensitizing effects to create a structure-activity relationship (SAR). Methods. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical solution-based chemical assay and and 2',7'-dichlorofluorescin diacetate (DCFH-DA) cellular-based assay were used to compare the free radical scavenging activity on the same molar concentration basis using the AML-2/DX100 cells which are characterized by the down-regulated expression of catalase and resulting supersensitiviy to hydrogen peroxide. The chemosensitization and cytotoxicity were determined by the MTT assay in the presence or absence of an anticancer drug using the P-glycoprotein-overexpressing AML-2 subline AML-2/D100 cells. Results. The antioxidant activity of the flavonoid (3,5,7,3’,4’-OH) was higher than that of the flavonoid (5,7,3’,4’-OH). Flavonoids substituted with the various number of OMe decreased antioxidant activity. Flavonoids with 7-OH or 5,7-OH groups have the highest cytotoxicity, and flavonoids with 5,7-OMe group intermediate cytotoxicity. The IC50 values of flavonoid (5,7-OMe, 3’,4’,5’-OMe) and flavonoid (5,7-OMe, 4’-OMe), 0.4 M and 1.4 M. The IC50 values of flavonoid (5,6,7-OMe, 3’,4’-OMe) and flavonoid (5,6,7-OMe, 3’,4’,5’-OMe), 3.2 uM and 0.9 M, respectively, and those of flavonoid (5,6,7-OMe, 3’,4’,5’-OMe) and flavonoid (5,7-OMe,3’,4’,5’-OMe) were 0.9 M and 0.4 M, respectively. Conclusions. These results suggest that flavonoids with 3-OH group play a positive role in antioxidant activities, flavonoids with 5-OH and/or 7-OH groups show the higher cytotoxicity, and flavonoids with 3’-OMe and/or 5’-OMe groups plays positive but 6-OMe groups negative roles in the P-glycoprotein (Pgp) inhibition. It is believed that these SAR results can be taken into account for the development of flavonoids with high therapeutic index.

Antioxidant Activities and Phenolic Composition of Apple Peel, Core and Flesh Extracts on Selected Apple Cultivars

2012 ◽  
Vol 554-556 ◽  
pp. 1103-1109 ◽  
Author(s):  
Gui Zhi Zhang ◽  
Bao Ping Ji ◽  
Gang Chen
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Total Phenolic ◽  
Phenolic Antioxidants ◽  
Antioxidant Power ◽  
Phenolic Contents ◽  
Apple Cultivars ◽  
Apple Peels

Phenolic antioxidants have multiple benefits to human health. Polyphenols are responsible for the antioxidant activity in apples. Antioxidant activities were assessed using the ferric reducing/antioxidant power (FRAP) and 2,2-dipheny l-1-picrylhydrazyl (DPPH) radical scavenging assays in different cultivars and different parts of apples grown in China. The phenolic compounds and antioxidant activities differed significantly among the four apple cultivars. Guoguang had the highest phenolic concentration and antioxidant activity and Golden Delicious had the lowest. The peels had the highest total phenolic and flavonoid contents followed by the cores and flesh. Anthocyanins were detected only in red apple peels. Peel and core had greater antioxidant activities than apple flesh. FRAP values were inversely correlated with phenolic contents, whereas no clear relationship could be observed between DPPH values and phenolic contents. The higher levels of phenolic compounds and antioxidant activities of apple peels and cores than flesh may be of technological interest as a valuable source of antioxidants.

scholarly journals Antioxidant Activities of Vaccinium vitis-idaea L. Leaves within Cultivars and Their Phenolic Compounds

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 844 ◽  
Author(s):  
Lina Raudone ◽  
Gabriele Vilkickyte ◽  
Lina Pitkauskaite ◽  
Raimondas Raudonis ◽  
Rimanta Vainoriene ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Positive Influence ◽  
Phenolic Profile ◽  
Structure Activity ◽  
The Subject ◽  
Potential Use

Lingonberry leaves are the subject of numerous studies because of antioxidant properties, positive influence on the health and potential use in the prevention and treatment of chronic diseases. In this work, the radical scavenging, reducing, chelating activities, and phenolic composition of ten lingonberry leaves cultivars, one subspecies, and one variety were investigated. Furthermore, the antioxidant activity of individual phenolic compounds, that can be found in lingonberry leaves, were analyzed, and structure-activity relationship was determined. Wide diversity for phenolic profile and antioxidant properties of lingonberry leaves has been observed in the present material. Cultivars ‘Kostromskaja rozovaja’, ‘Rubin’, and Vaccinium vitis-idaea var. leucocarpum surpassed all others tested cultivars and lower taxa by contents of phenolic compounds and antioxidant activity. Leaves of lingonberry cultivars and lower taxa are rich in arbutin, flavonol glycosides, proanthocyanidins, and the latter were considered to be the major contributor to antioxidant properties of lingonberry leaves.

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.

Synthesis, Antioxidant Activity and Theoretical Investigation of Isoxazolines Derivatives of Monoterpenoids

2019 ◽  
Vol 16 (6) ◽  
pp. 501-510
Author(s):  
Melek Gul ◽  
Serpil Eryılmaz
Keyword(s):  
Antioxidant Activity ◽  
Biological Activity ◽  
Antioxidant Activities ◽  
Computational Study ◽  
Chemical Reactivity ◽  
Radical Scavenging ◽  
Basis Set ◽  
Electrophilicity Index ◽  
Theoretical Approaches ◽  
Derivatives Of

The 3+2 cycloaddition reactions are important to generate five-membered heterocyclic compounds as well as altering biological activity effects based on structure. In the study, we synthesized new isoxazoline derivatives of different monoterpenoids and examined the structure analysis using spectroscopical analysis methods, reveal changes in the theoretical analysis related to the biological activity. These new compounds exhibit antioxidant activities; DPPH radical scavenging, ferric reducing, metal chelating activities which are significantly higher than the related commercial monoterpenoids. Theoretical approaches on the compounds containing isoxazole moiety have been performed by the DFT/B3LYP/method, 6-31G(d,p) basis set in the ground state. The global and local chemical reactivity properties of the compounds were investigated by considering the values of electronegativity, global hardness-softness, electronic chemical potential, electrophilicity index and condensed Fukui functions, local softness and local electrophilicity index. Furthermore, total energy, FMOs energy values and the dipole moment (µ), mean polarizability (α), and first order hyperpolarizability (β) values were analysed at the theoretical level to examine the polarizability characteristics of the compounds. The antioxidant activity values of the newly synthesized compounds were compared with a finding of the computational study. The results obtained exhibited good correlation on some parameters.

Antioxidant activity of cookiessupplemented with sugarbeet dietary fiber

2011 ◽  
pp. 151-157 ◽  
Author(s):  
Marijana B. Saka ◽  
Julianna F. Gyura ◽  
Aleksandra Mišan ◽  
Zita I. Šereš ◽  
Biljana S. Pajin ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Shelf Life ◽  
Dietary Fiber ◽  
Wheat Flour ◽  
Room Temperature ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Functional Characteristics

The antioxidant activity of cookies prepared by the addition of sugarbeet dietary fibers was investigated in order to estimate their influence on functional characteristics and shelf-life of cookies. Treated fiber (TF) was obtained from sugarbeet by extraction with sulfurous acid (75 °C at pH = 5.7during 60 min) and treatment with hydrogen peroxide (20 g/LH2O2 at pH = 11 during 24 h). The fiber obtained was dried (80 °C), ground and sieved. TF was investigated in comparison with commercially available Fibrex®. The cookies were prepared by the addition of 0, 7, 9 and 11% of sugarbeet dietary fiber as a substitute for wheat flour in the formulation of cookies. The antioxidant properties of cookies were tested every 7 days using a DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity test during 6 weeks of storage at room temperature (23 ± 1 ºC). The obtained results indicated that substitution of wheat flour with Fibrex® in the formulation of cookies upgraded the antioxidant activity, i.e. the functional characteristics of Fibrex®-enriched cookies and could prolong their shelf-life. In contrast, TF did not increase the antioxidant activity of TF-enriched cookies. The better antioxidant activities of Fibrex®-enriched cookies could be attributed to the presence of ferulic acid.

scholarly journals Characterization of Phytoconstituents from Alcoholic Extracts of Four Woody Species and Their Potential Uses for Management of Six Fusarium oxysporum Isolates Identified from Some Plant Hosts

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1325
Author(s):  
Mohamed Z. M. Salem ◽  
Abeer A. Mohamed ◽  
Hayssam M. Ali ◽  
Dunia A. Al Al Farraj
Keyword(s):  
Antioxidant Activity ◽  
Free Radical ◽  
Benzoic Acid ◽  
Fusarium Oxysporum ◽  
Leaf Extract ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Bark Extract ◽  
Leaf Extracts ◽  
Conium Maculatum

Background: Trees are good sources of bioactive compounds as antifungal and antioxidant activities. Methods: Management of six molecularly identified Fusarium oxysporum isolates (F. oxy 1, F. oxy 2, F. oxy 3, F. oxy 4, F. oxy 5 and F. oxy 6, under the accession numbers MW854648, MW854649, MW854650, MW854651, and MW854652, respectively) was assayed using four extracts from Conium maculatum leaves, Acacia saligna bark, Schinus terebinthifolius wood and Ficus eriobotryoides leaves. All the extracts were analyzed using HPLC-VWD for phenolic and flavonoid compounds and the antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and β-carotene-linoleic acid (BCB) bleaching assays. Results: In mg/kg extract, the highest amounts of polyphenolic compounds p-hydroxy benzoic, benzoic, gallic, and rosmarinic acids, with 444.37, 342.16, 311.32 and 117.87, respectively, were observed in C. maculatum leaf extract; gallic and benzoic acids with 2551.02, 1580.32, respectively, in A. saligna bark extract; quinol, naringenin, rutin, catechol, and benzoic acid with 2530.22, 1224.904, 798.29, 732.28, and 697.73, respectively, in S. terebinthifolius wood extract; and rutin, o-coumaric acid, p-hydroxy benzoic acid, resveratrol, and rosmarinic acid with 9168.03, 2016.93, 1009.20, 1156.99, and 574.907, respectively, in F. eriobotryoides leaf extract. At the extract concentration of 1250 mg/L, the antifungal activity against the growth of F. oxysporum strains showed that A. saligna bark followed by C. maculatum leaf extracts had the highest inhibition percentage of fungal growth (IPFG%) against F. oxy 1 with 80% and 79.5%, F. oxy 2 with 86.44% and 78.9%, F. oxy 3 with 86.4% and 84.2%, F. oxy 4 with 84.2, and 82.1%, F. oxy 5 with 88.4% and 86.9%, and F. oxy 6 with 88.9, and 87.1%, respectively. For the antioxidant activity, ethanolic extract from C. maculatum leaves showed the lowest concentration that inhibited 50% of DPPH free radical (3.4 μg/mL). Additionally, the same extract observed the lowest concentration (4.5 μg/mL) that inhibited BCB bleaching. Conclusions: Extracts from A. saligna bark and C. maculatum leaves are considered potential candidates against the growth of F. oxysporum isolates—a wilt pathogen—and C. maculatum leaf as a potent antioxidant agent.

In Vitro Antioxidant Activity Metaplexis Japonica Makino Extract and Derivatives

2014 ◽  
Vol 955-959 ◽  
pp. 387-389 ◽  
Author(s):  
Bao Qing Wang
Keyword(s):  
Antioxidant Activity ◽  
Linoleic Acid ◽  
Ethyl Acetate ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Acid Test ◽  
Acetone Extracts ◽  
Β Carotene ◽  
Ethyl Acetate Extracts

Antioxidant activities of acetone and ethyl acetate extracts from Metaplexis japonica Makino, one of famous medicine plants in the eastnorth region of China, named luomo in Chinese, were examined by a DPPH (1,1-Diphenyl-2-picrylhydrazyl) radical-scavenging assay and a β-carotene-linoleic acid test. In DPPH, the antioxidant activity of the acetone extracts, ethyl acetate extracts and derivative were IC50 were 313.21, 266.92 and 118.78μg/mL, respectively. In the β-carotene-linoleic acid test, IC50 were 285.09, 351.57 and 123.89μg/mL. It was concluded that Metaplexis japonica Makino and its derivatives might be a potential natural source of antioxidants .

scholarly journals Antioxidant and Anticancer Activities of Wampee (Clausena lansium(Lour.) Skeels) Peel

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
K. Nagendra Prasad ◽  
Jing Hao ◽  
Chun Yi ◽  
Dandan Zhang ◽  
Shengxiang Qiu ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Ethyl Acetate ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Total Phenolic ◽  
Liver Carcinoma ◽  
Scavenging Activity ◽  
Anticancer Activities

Antioxidant activities of wampee peel extracts using five different solvents (ethanol, hexane, ethyl acetate, butanol and water) were determined by using in-vitro antioxidant models including total antioxidant capability, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, reducing power, and superoxide scavenging activity. Ethyl acetate fraction (EAF) exhibited the highest antioxidant activity compared to other fractions, even higher than synthetic antioxidant butylated hydroxyl toluene (BHT). In addition, the EAF exhibited strong anticancer activities against human gastric carcinoma (SGC-7901), human hepatocellular liver carcinoma (HepG-2) and human lung adenocarcinoma (A-549) cancer cell lines, higher than cisplatin, a conventional anticancer drug. The total phenolic content of wampee fraction was positively correlated with the antioxidant activity. This is the first report on the antioxidant and anticancer activities of the wampee peel extract. Thus, wampee peel can be used potentially as a readily accessible source of natural antioxidants and a possible pharmaceutical supplement.

ASSESSMENT OF PHYTOCHEMICALS, TOTAL PHENOL, FLAVONOID CONTENT AND IN VITRO ANTIOXIDANT PROPERTY OF LARGE CARDAMOM EXTRACTS

INDIAN DRUGS ◽  
2021 ◽  
Vol 58 (10) ◽  
pp. 34-41
Author(s):  
Kanthlal S. K. ◽  
Jipnomon Joseph ◽  
Bindhu P. Paul ◽  
Vijayakumar M ◽  
Rema Shree A. B. ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Antioxidant Property ◽  
Bioactive Constituents ◽  
Preliminary Assessment ◽  
Reducing Power Assay ◽  
Large Cardamom

Amomum subulatum, commonly known as large or black cardamom, is a commonly used spice in Indian kitchens and is traditionally used to treat various ailments. To add more knowledge about the medicinal values of the fruit, this study was conducted to evaluate the in vitro antioxidant activities of aqueous, methanol, ethanol, hydro alcohol, ethyl acetate, acetone and chloroform extracts of the fruit. Preliminary assessment was done to detect the presence of phytoconstituents using identification tests. The antioxidant activity was measured by employing methods such as diphenylpicrylhydrazyl (DPPH) radical scavenging assay, total antioxidant activity equivalent to ascorbic acid, reducing power assay and superoxide anion scavenging assay. The antioxidant activities were compared with their respective phenol and flavonoid contents. Preliminary assessment revealed that large cardamom fruit is a good source of all the bioactive constituents as well as phenol and flavonoid essential for medicinal values. The extract obtained by polar solvents showed the highest antioxidant efficacy in relation to its phenol content. Also, all the solvent-soluble fractions showed a concentration-dependent antioxidant effect. Results from our study prove that large cardamom can alleviate oxidative stress, suggesting the potential of large cardamom as a functional food

Sign in / Sign up

Export Citation Format

Share Document