Structure-activity relationships of anti-tyrosinase and antioxidant activities of cinnamic acid and its derivatives

2021 ◽  
Author(s):  
Jianmin Chen ◽  
Mengnan Ran ◽  
Meixia Wang ◽  
Xinying Liu ◽  
Siwan Liu ◽  
...  
Keyword(s):  
Cinnamic Acid ◽  
Phenyl Ring ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Ic50 Value

Abstract The related structure-activity relationships (SARs) of cinnamic acid and its derivates have not been studied in details yet. Herein, anti-tyrosinase and antioxidant activities of 18 compounds were evaluated. The results demonstrated that the substituents on the phenyl ring of cinnamic acid led to the enhancement of the inhibition on monophenolase and the weakening of the inhibition on diphenolase. Among these tested compounds, 9 was firstly discovered as a tyrosinase inhibitor in a reversible competitive manner with IC50 value of 68.6 ± 4.2 μM. Docking results demonstrated 9 located into the catalytic center of tyrosinase. Antioxidant assay indicated that only one hydroxyl group on the phenyl ring was not enough to possess the radical scavenging activity, and the number of hydroxyl groups may be more important. This study will be helpful for development of new cinnamic acid derivates as tyrosinase inhibitors and antioxidants with higher efficacy.

scholarly journals DPPH-Scavenging Activities and Structure-Activity Relationships of Phenolic Compounds

2010 ◽  
Vol 5 (11) ◽  
pp. 1934578X1000501 ◽  
Author(s):  
Cheng-Dong Zheng ◽  
Gang Li ◽  
Hu-Qiang Li ◽  
Xiao-Jing Xu ◽  
Jin-Ming Gao ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Antiradical Activity ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Basic Structure ◽  
Hydroxyl Group ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Dpph Scavenging ◽  
Dpph Radical Scavenging

Thirty-eight phenolic compounds (including 31 flavonoids) were examined for their DPPH radical-scavenging activities, and structure-activity relationships were evaluated. Specifically, the presence of an Ortho-dihydroxyl structure in phenolics is largely responsible for their excellent antiradical activity. 3-Hydroxyl was also essential to generate a high radical-scavenging activity. An increasing number of hydroxyls on flavones with a 3′,4′-dihydroxyl basic structure, the presence of a third hydroxyl group at C-5′, a phloroglucinol structure, glycosylation and methylation of the hydroxyls, and some other hydroxyls, for example 5-, and 7-hydroxyl in ring A, decreased the radical-scavenging activities of flavonoids and other phenolics.

scholarly journals Enhancement of Antioxidant and Hydrophobic Properties of Alginate via Aromatic Derivatization: Preparation, Characterization, and Evaluation

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2575
Author(s):  
Smaher M. Elbayomi ◽  
Haili Wang ◽  
Tamer M. Tamer ◽  
Yezi You
Keyword(s):  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Benzoyl Group ◽  
Antioxidant Evaluation ◽  
Thermo Stability

The preparation of bioactive polymeric molecules requires the attention of scientists as it has a potential function in biomedical applications. In the current study, functional substitution of alginate with a benzoyl group was prepared via coupling its hydroxyl group with benzoyl chloride. Fourier transform infrared spectroscopy indicated the characteristic peaks of aromatic C=C in alginate derivative at 1431 cm−1. HNMR analysis demonstrated the aromatic protons at 7.5 ppm assigned to benzoyl groups attached to alginate hydroxyl groups. Wetting analysis showed a decrease in hydrophilicity in the new alginate derivative. Differential scanning calorimetry and thermal gravimetric analysis showed that the designed aromatic alginate derivative demonstrated higher thermo-stability than alginates. The aromatic alginate derivative displayed high anti-inflammatory properties compared to alginate. Finally, the in vitro antioxidant evaluation of the aromatic alginate derivative showed a significant increase in free radical scavenging activity compared to neat alginate against DPPH (2,2-diphenyll-picrylhydrazyl) and ABTS free radicals. The obtained results proposed that the new alginate derivative could be employed for gene and drug delivery applications.

Synthesis and Biological Activities of Hydroxytyrosol Ester Derivatives

2020 ◽  
Vol 42 (1) ◽  
pp. 109-109
Author(s):  
Hao Zang Hao Zang ◽  
Qian Xu Qian Xu ◽  
Luyun Zhang Luyun Zhang ◽  
Guangqing Xia Guangqing Xia ◽  
Jiaming Sun and Junyi Zhu Jiaming Sun and Junyi Zhu
Keyword(s):  
Ascorbic Acid ◽  
Antioxidant Activities ◽  
Biological Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Acetylcholinesterase Inhibition ◽  
Hydroxyl Group ◽  
Scavenging Activity ◽  
Antioxidant Power ◽  
Better Than

A series of hydroxytyrosol (HT) derivatives were synthesized by modification of alcohol hydroxyl group of HT, twenty-five target compounds were obtained and characterized by NMR and HRMS. The antioxidant activities of those compounds were evaluated in three different assays. Except 3e and 3y, all other compounds demonstrated significant 2,2and#39;-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical cation scavenging activity ranging from IC50 3.4 to 24.4 μM, which were more potent than L-ascorbic acid (IC50=24.8 μM). Compounds 3b-3d, 3f-3k, 3m-3x were better than Trolox (18.3 M). Moreover, the ferric reducing antioxidant power (FRAP) of all compounds were discovered to be more potent than L-ascorbic acid (40.7 mmol/g), except 3e, all other compounds (141.5-202.1 mmol/g) were better than Trolox (94.7 mmol/g). Compounds 3a-3d, 3f-3j, 3l-3m, 3o, 3q, 3t, 3v-3y exhibited more potent hydroxyl radical scavenging activity (IC50=245.1-475.1 M) than L-ascorbic acid (554.4 M) and Trolox (500.4 M). Compounds 3q, 3t and 3y exhibited more potent -Glucosidase inhibition activity (39.1-52.4 M) than Acarbose (60.9 M). Compounds 3a, 3d, 3f-3m, 3s-3t, 3v-3y showed some acetylcholinesterase inhibition activities, compounds 3a, 3d, 3f-3j, 3l-3m, 3o-3p, 3s-3t, 3w showed some butyrylcholinesterase inhibition activities.

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 Free Radical Scavenging Activities of Naturally Occurring and Synthetic Analogues of Sea Urchin Naphthazarin Pigments

2012 ◽  
Vol 7 (7) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Natalia K. Utkina ◽  
Natalia D. Pokhilo
Keyword(s):  
Antioxidant Activities ◽  
Sea Urchins ◽  
Radical Scavenging ◽  
Natural Antioxidants ◽  
Hydroxyl Groups ◽  
Echinochrome A ◽  
Naturally Occurring ◽  
Structure Activity ◽  
Potential Use ◽  
Free Radical Scavenging Activities

Antioxidant activities of minor pigments of sea urchins (1–5) and synthetic naphthazarins (7–13) were evaluated and compared with echinochrome A (6) using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) scavenging assays. Structure-activity relationships showed that the antioxidant activities of the tested compounds depended on the number and positions of hydroxyl groups. Compounds bearing 3 or 2 hydroxyl groups on a naphthazarin core (5,8-dihydroxy-1,4-naphthoquinone) were the most active in both assays. Echinochrome A (6) (IC50 7.0 μM) and its monomethyl ethers 7 (IC50 15.0 μM) and 8 (IC50 15.0 μM) displayed stronger activities than Trolox (IC50 16.0 μM) in the DPPH and ABTS assays (TE = 3.41, 2.35, and 2.35 mM, respectively). Compounds with either one or without hydroxyl groups on a naphthazarin core displayed activities significantly lower than Trolox in both assays. These results suggest that hydroxylated naphthazarin pigments of sea urchins have a potential use as natural antioxidants.

Effect of reserpine on the structure–activity relationships for the inhibition of noradrenaline uptake in adrenergic nerves in rat and rabbit ventricle by phenethylamines

1977 ◽  
Vol 55 (2) ◽  
pp. 196-205 ◽  
Author(s):  
D. M. Paton ◽  
D. S. Golko
Keyword(s):  
Phenolic Hydroxyl ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Noradrenaline Uptake ◽  
Inhibitory Potency ◽  
Sympathomimetic Amines ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Phenolic Hydroxyl Groups ◽  
Inhibitory Agents

Ventricular tissue from the hearts of normal and reserpine-pretreated rats and rabbits were exposed to pargyline, tropolone, and hydrocortisone to inhibit monoamine oxidase (EC 1.4.3.4), catechol-O-methyltransferase (EC 2.1.1.6), and extraneuronal uptake, respectively. To examine the structure–activity relationships for inhibition of noradrenaline uptake, the inhibition of the 10-min uptake of (−)-[3H]noradrenaline by sympathomimetic amines was determined and ID50 values calculated. In reserpine-pretreated tissues, the most potent inhibitory agents studied were amines lacking phenolic hydroxyl groups (i.e., β-phenethylamine, (+)- and (−)-amphetamine). Addition of one or two phenolic hydroxyl groups, a β-hydroxyl group, or an N-methyl group generally decreased inhibitory potency, while α-methylation had little effect. Amines with large N-substitution and phenolic O-methyl groups were the least potent inhibitory agents. The stereoisomers of amphetamine, noradrenaline, and metaraminol did not differ in potency. However, the stereoisomers of ephedrine did, the order of potency being (−)-ephedrine > (±)-ephedrine > (+)-ψ-ephedrine > (−)-ψ-ephedrine. These structure–activity relationships are the same as those previously found for the acceleration of efflux of extragranular noradrenaline. Amines also released (−)-[3H]noradrenaline from reserpine-pretreated tissues. Results obtained using ventricles from nonreserpinized rats and rabbits showed two important differences. Firstly, sympathomimetic amines were much less potent releasers of (−)-[3H]noradrenaline from such tissues. Secondly, amines lacking phenolic hydroxyl groups were, on the average, five- to seven-fold less potent as inhibitors of (−)-[3H]-noradrenaline uptake. However, the inhibitory potencies of phenolethylamines and catecholamines were generally similar to those found in reserpine-pretreated tissues. These studies have demonstrated that reserpine pretreatment potentiates the inhibitory potency of phenethylamines and phenylethanolamines.

scholarly journals Evaluation of the radical scavenging activity of a series of synthetic hydroxychalcones towards the DPPH radical

2011 ◽  
Vol 76 (4) ◽  
pp. 491-497 ◽  
Author(s):  
Iva Todorova ◽  
Daniela Batovska ◽  
Bistra Stamboliyska ◽  
Stoyan Parushev
Keyword(s):  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Experimental Results ◽  
Scavenging Activity ◽  
Dpph Radical ◽  
Structure Activity Relationships ◽  
Aryl Aldehydes ◽  
Structure Activity ◽  
Dpph Radical Scavenging ◽  
Important Structure

Sixteen hydroxychalcones were synthesized in sufficient purity by the Claisen-Schmidt condensation between appropriate acetophenones and aryl aldehydes. All the compounds were evaluated for their ability to scavenge the stable free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. Important structure-activity relationships were observed that strongly contribute to the knowledge for the design of DPPH radical scavenging chalcones. Relevant theoretical parameters were computed in an attempt to understand and explain the obtained experimental results.

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.

scholarly journals Antioxidant and Antidiabetic Activities of Fresh Aqueous Pink Petals of Indian Lotus-Nelumbo nucifera Gaertn.

2019 ◽  
Vol 9 (5) ◽  
pp. 82-88
Author(s):  
K Saraswathi ◽  
C Sivaraj ◽  
B Fransila ◽  
P Arumugam
Keyword(s):  
Radical Cation ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Nelumbo Nucifera ◽  
Alpha Amylase ◽  
Scavenging Activity ◽  
Dpph Radical ◽  
Zone Of Inhibition ◽  
Ic50 Value

The genus Nelumbo is endowed with a number of medicinally important activities antidiabetic, antipyretic, anti-inflammatory, anti-cancerous, antimicrobial, antiviral and anti-obesity properties. Furthermore, Nelumbo nucifera flowers are served as healthy beverages to treat hypertension, cancer, diarrhea, fever, weakness, infection and body heat imbalance. It has been widely used in folk medicine for the treatment of various inflammatory and infectious diseases. Current research studies were carried out for evaluating the antioxidant, antidiabetic and antibacterial activities of fresh aqueous pink petals of Nelumbo nucifera. Antioxidant activities such as DPPH˙ radical, Superoxide (O2.-) radical, ABTS●+ radical cation, phosphomolybdenum reduction and Fe3+ reduction were carried out for fresh aqueous pink petals of Nelumbo nucifera. The maximum DPPH˙ radical scavenging activity was 88.33±0.47% at 300 µg/mL concentration and the IC50 value was 131.68 µg/mL concentration. The maximum superoxide (O2.-) radical scavenging activity was 86.76±0.31% at 120 µg/mL concentration and the IC50 value was 21.31 µg/mL concentration. The maximum ABTS●+ radical cation scavenging activity was 69.55±0.26% at 30 µg/mL concentration and the IC50 value was 10.82 µg/mL concentration respectively. The maximum Mo6+ reduction was 84.54±0.21% at 45 µg/mL concentration and the RC50 value of Mo6+ reduction was 25.79 µg/mL concentration. The maximum Fe3+ reduction was 56.00±0.38% at 300 µg/mL concentration and the RC50 value of Fe3+ reduction was 177.30 µg/mL concentration respectively. The maximum alpha amylase enzyme inhibition was 66.37±0.10% at 300 µg/mL concentration and the IC50 value was 63.84 µg/mL concentration respectively. The antibacterial activity of fresh aqueous pink petals of Nelumbo nucifera showed maximum zone of inhibition of 14 mm for B. subtilis and minimum zone of inhibition of 10 mm for E. coli at 375 µg/mL concentration.  Keywords: Antioxidant, Superoxide (O2.-) radical, ABTS●+ radical cation, Fe3+ reduction and alpha-amylase.

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