scholarly journals Antioxidant Activity of 1’-Hydroxyethylnaphthazarins and their Derivatives

2017 ◽  
Vol 12 (12) ◽  
pp. 1934578X1701201
Author(s):  
Natalia K. Utkina ◽  
Natalia D. Pokhilo
Keyword(s):  
Antioxidant Activity ◽  
Radical Cation ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Hydroxyl Group ◽  
Side Chains ◽  
Scavenging Activity ◽  
Structure Activity

The ABTS•+ radical cation scavenging activity of known (2-5, 9, 10) and new (6-8) 1’-hydroxyethylnaphthazarins and their products of esterification and etherification was evaluated and a structure-activity relationship was studied. It was shown, that the structure of side chains does not affect the radical scavenging activity of 1’-hydroxyethylnaphthazarins and their derivatives. The presence of methoxyl groups on the naphthazarin core slightly enhanced the antioxidant activity of compounds compared with compounds without methoxyl groups. The presence of the additional hydroxyl group on the naphthazarin moiety of isonorlomazarin (5) and its derivative (6) is essential for the activity.

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.

Synthesis, radical scavenging activity and structure–activity relationship of uric acid analogs

MedChemComm ◽  
2013 ◽  
Vol 4 (3) ◽  
pp. 527 ◽  
Author(s):  
Daisuke Yasuda ◽  
Kyoko Takahashi ◽  
Tomohiro Kakinoki ◽  
Yoko Tanaka ◽  
Tomoyuki Ohe ◽  
...  
Keyword(s):  
Uric Acid ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Scavenging Activity ◽  
Structure Activity ◽  
Relationship Of

scholarly journals Hepatotoxicity and antioxidant activity of some new N,N′-disubstituted benzimidazole-2-thiones, radical scavenging mechanism and structure-activity relationship

2018 ◽  
Vol 11 (3) ◽  
pp. 353-369 ◽  
Author(s):  
Neda O. Anastassova ◽  
Anelia Ts. Mavrova ◽  
Denitsa Y. Yancheva ◽  
Magdalena S. Kondeva-Burdina ◽  
Virginia I. Tzankova ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Structure Activity

scholarly journals Identification of Six Flavonoids as Novel Cellular Antioxidants and Their Structure-Activity Relationship

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Qiang Zhang ◽  
Wenbo Yang ◽  
Jiechao Liu ◽  
Hui Liu ◽  
Zhenzhen Lv ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Absorption Capacity ◽  
Activity Relationship ◽  
Antioxidant Enzyme Activities ◽  
Structure Activity ◽  
Low Cytotoxicity ◽  
Cellular Antioxidants

This study is aimed at determining the relationship of flavonoid structures to their chemical and intracellular antioxidant activities. The antioxidant activities of 60 flavonoids were investigated by three different antioxidant assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, oxygen radical absorption capacity (ORAC), and cellular antioxidant activity (CAA) assays. The result showed 6 flavonoids as good cellular antioxidants evaluated for the first time. The cellular antioxidant activities of compounds 7-methoxy-quercetin, 3-O-methylquercetin, 8-hydroxy-kaempferol, quercetin-3-O-α-arabinofuranose, kaempferol-7-O-glucopyranoside, and luteolin6-C-glucoside were linked with the upregulation of antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase). A structure-activity relationship suggested that 2,3-double bond, 4-keto groups, 3′,4′-catechol structure, and 3-hydroxyl in the flavonoid skeleton played important roles in the antioxidant behavior. Furthermore, the cell proliferative assay revealed a low cytotoxicity for 3-O-methylquercetin. The present results provide valuable information for the dietary application of flavonoids with different structures for high antioxidant.

scholarly journals Structure Activity Relationship, Drug Likeness and Evaluation of Antioxidant Activity of Some Mannich Bases of Dihydropyrimidinones

2019 ◽  
Vol 31 (8) ◽  
pp. 1767-1773
Author(s):  
Ravinder Mamidala ◽  
Solomon Raj S. Bhimathati ◽  
Aparna Vema
Keyword(s):  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Mannich Bases ◽  
Free Radical Scavenging ◽  
Activity Relationship ◽  
Chemical Parameters ◽  
Structure Activity ◽  
Physico Chemical

A series of 21 O- and N-Mannich bases of 3,4-dihydropyrimidinones (2a-j and 3a-k) were synthesized by using microwave irradiation technique by multi-component reaction in two steps. All the compounds were evaluated for their free radical scavenging activity by four methods. Structure activity relationship studies revealed that the compounds 2h, 2g, 3h and 3g exhibited profound antioxidant properties compared to standard ascorbic acid. Among O- and N-Mannich bases, N-Mannich bases were found to be more potent in scavenging free radicals. The correlation between structure and activities of these compounds with concern to drug likeliness profile and other physico-chemical parameters are portrayed and verified experimentally.

scholarly journals Structure-activity relationship and MM2 energy minimized conformational analysis of quercetin and its derivatives in the DPPH• radical scavenging capacity

BIBECHANA ◽  
2020 ◽  
Vol 17 ◽  
pp. 20-27
Author(s):  
Gan B Bajracharya ◽  
Mohan Paudel ◽  
Rajendra K. C. ◽  
Sajan L. Shyaula
Keyword(s):  
Antioxidant Activity ◽  
Methyl Ether ◽  
Radical Scavenging ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Dihedral Angles ◽  
Structure Activity ◽  
Scavenging Capacity ◽  
Ic50 Values ◽  
High Antioxidant Activity

Antioxidant activity of quercetin (1) and its derivatives (2-15) was evaluated by using DPPH assay and IC50 values were calculated. Dihedral angles α of C3-C2-C1’-C6’ chain and β of O1-C2-C-1’-C2’ chain between AC and B rings of these flavones were determined by using MM2 energy minimized structures. Structure-activity relationship study revealed that quercetin (1), quercetin-5-methyl ether (2), quercetin-3’-methyl ether (3) and quercetin-3’,5-dimethyl ether (4) displaying a high antioxidant activity (IC50 = 47.20-119.27 μM) possess similar dihedral angles (α 11.1-11.5º and β 6.3-6.6º). Mono- and/or di-methoxy substituent(s) at 3’ and 5 positions of the flavone are most suitable for the preservation of the antioxidant capacity while retaining conformational geometry. BIBECHANA 17 (2020) 19-26

scholarly journals Antioxidant Activity in Rheum emodi Wall (Himalayan Rhubarb)

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2555
Author(s):  
Sang Koo Park ◽  
Yoon Kyung Lee
Keyword(s):  
Antioxidant Activity ◽  
Ethyl Acetate ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Ethyl Acetate Fraction ◽  
Total Phenolic ◽  
Scavenging Activity ◽  
Polyphenol Content ◽  
Abts Assay ◽  
Ic50 Values

Using natural products as antioxidant agents has been beneficial to replace synthetic products. Efforts have been made to profile the antioxidant capacities of natural resources, such as medicinal plants. The polyphenol content of Himalayan rhubarb, Rheum emodi wall, was measured and the antioxidant activity was determined using DPPH and ABTS+ assay, and the oxidative stress was assessed using SOD enzymatic assay. Five different solvent fractions, n-hexane, n-butanol, ethyl acetate, dichloromethane, and water, were used for screening the antioxidant capacity in effort to determine the optimum extraction solvent. The total phenolic contents for R. emodi fractions ranged from 27.76 to 209.21 mg of gallic acid equivalents (GAE)/g of dry weight. DPPH and ABTS+ assay results are presented into IC50 values, ranged from 21.52 to 2448.79 μg/mL and 90.25 to 1718.05 μg/mL, respectively. The ethyl acetate fraction had the highest antioxidant activity among other fractions. Also, n-butanol and water fractions showed significantly lower IC50 values than the positive control in DPPH radical scavenging activity. The IC50 values of SOD assay of fractions ranged from 2.31 to 64.78 μg/mL. A similar result was observed with ethyl acetate fraction showing the highest SOD radical scavenging activity. The study suggests that the ethyl acetate fraction of R. emodi possess the strongest antioxidant activity, thus the most efficient in extracting antioxidant contents. Moreover, a highly significant correlation was shown between total polyphenol content and antioxidant activity screening assays. The compounds related to the antioxidant activity of R. emodi were identified to myricitrin, myricetin 3-galloyl rhamnoside, and myricetin, which have not been reported in studies about R. emodi before.

scholarly journals The Inhibitory Effects of Plant Derivate Polyphenols on the Main Protease of SARS Coronavirus 2 and Their Structure–Activity Relationship

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1924
Author(s):  
Thi Thanh Hanh Nguyen ◽  
Jong-Hyun Jung ◽  
Min-Kyu Kim ◽  
Sangyong Lim ◽  
Jae-Myoung Choi ◽  
...  
Keyword(s):  
Structure Activity Relationship ◽  
Garlic Extract ◽  
Activity Relationship ◽  
Hydroxyl Group ◽  
Inhibitory Effects ◽  
Structure Activity ◽  
Main Protease ◽  
Ic50 Values ◽  
Km Value ◽  
Novel Coronavirus

The main protease (Mpro) is a major protease having an important role in viral replication of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the novel coronavirus that caused the pandemic of 2020. Here, active Mpro was obtained as a 34.5 kDa protein by overexpression in E. coli BL21 (DE3). The optimal pH and temperature of Mpro were 7.5 and 37 °C, respectively. Mpro displayed a Km value of 16 μM with Dabcyl-KTSAVLQ↓SGFRKME-Edans. Black garlic extract and 49 polyphenols were studied for their inhibitory effects on purified Mpro. The IC50 values were 137 μg/mL for black garlic extract and 9–197 μM for 15 polyphenols. The mixtures of tannic acid with puerarin, daidzein, and/or myricetin enhanced the inhibitory effects on Mpro. The structure–activity relationship of these polyphenols revealed that the hydroxyl group in C3′, C4′, C5′ in the B-ring, C3 in the C-ring, C7 in A-ring, the double bond between C2 and C3 in the C-ring, and glycosylation at C8 in the A-ring contributed to inhibitory effects of flavonoids on Mpro.

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