scholarly journals Exopolysaccharides from the Energy Microalga Strain Botryococcus braunii: Purification, Characterization, and Antioxidant Activity

Foods ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 110
Author(s):  
Wei-Nan Wang ◽  
Tao Li ◽  
Yi Li ◽  
Ying Zhang ◽  
Hua-Lian Wu ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Hydroxyl Radicals ◽  
Inhibitory Concentration ◽  
Deae Cellulose ◽  
Botryococcus Braunii ◽  
Pyranose Ring ◽  
Structure Activity ◽  
Potential Applications ◽  
Relationship Of ◽  
Cellulose Column

Botryococcus braunii, a prestigious energy microalga, has recently received widespread attention because it can secrete large amounts of exopolysaccharides (EPS) with potential applications in food, cosmetics, and nutraceuticals. Unfortunately, the insufficiency of research on the bioactivity and structure–activity relationship of B. braunii EPS has impeded the downstream applications. In the present study, alcohol precipitation, deproteinization, and DEAE-cellulose column chromatography were used to extract and purify B. braunii SCS-1905 EPS. It was found that B. braunii SCS-1905 EPS were high-molecular-weight heteropolysaccharides containing uronic acid (7.43–8.83%), protein (2.30–4.04%), and sulfate groups (1.52–1.95%). Additionally, the EPS primarily comprised galactose (52.34–54.12%), glucose (34.60–35.53%), arabinose (9.41–10.32%), and minor amounts of fucose (1.80–1.99%), with the presence of a pyranose ring linked by a β-configurational glycosidic bond. Notably, the antioxidant activity of crude exopolysaccharides (CEPS) was stronger, and the half maximal inhibitory concentration (IC50) for ABTS and hydroxyl radicals was significantly lower than that of deproteinized exopolysaccharides (DEPS). Overall, this study indicated a potential application of B. braunii SCS-1905 EPS as a natural antioxidant. In summary, B. braunii EPS could be used as a potential feedstock for the production of antioxidant health foods.

Phenolic Imidazole Derivatives with Dual Antioxidant/Antifungal Activity: Synthesis and Structure-Activity Relationship

2019 ◽  
Vol 15 (4) ◽  
pp. 341-351 ◽  
Author(s):  
Ana P. Bettencourt ◽  
Marián Castro ◽  
João P. Silva ◽  
Francisco Fernandes ◽  
Olga P. Coutinho ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Antifungal Activity ◽  
Organic Molecules ◽  
Inhibitory Concentration ◽  
Yeast Species ◽  
Dpph Radical ◽  
Dpph Assay ◽  
Gram Negative ◽  
Structure Activity ◽  
Deoxyribose Degradation

Background: Previous publications show that the addition of a phenolic antioxidant to an antifungal agent, considerably enhances the antifungal activity. Objective: Synthesis of novel compounds combining phenolic units with linear or cyclic nitrogencontaining organic molecules with antioxidant/antifungal activity using methodologies previously developed in the group. Methods: Several N- [1,2-dicyano-2- (arylidenamino) vinyl]-O-alkylformamidoximes 3 were synthesized and cyclized to 4,5-dicyano-N- (N´-alcoxyformimidoyl)-2-arylimidazoles 4 upon reflux in DMF, in the presence of manganese dioxide or to 6-cyano-8-arylpurines 5 when the reagent was refluxed in acetonitrile with an excess of triethylamine. These compounds were tested for their antioxidant activity by cyclic voltammetry, DPPH radical (DPPH•) assay and deoxyribose degradation assay. The minimum inhibitory concentration (MIC) of all compounds was evaluated against two yeast species, Saccharomyces cerevisiae and Candida albicans, and against bacteria Bacillus subtilis (Gram-positive) and Escherichia coli (Gram negative). Their cytotoxicity was evaluated in fibroblasts. Results: Among the synthetised compounds, five presented higher antioxidant activity than reference antioxidant Trolox and from these compounds, four presented antifungal activity without toxic effects in fibroblasts and bacteria. Conclusion: Four novel compounds presented dual antioxidant/antifungal activity at concentrations that are not toxic to bacteria and fibroblasts. The active molecules can be used as an inspiration for further studies in this area.

Structure–activity relationship of nanostructured ceria for the catalytic generation of hydroxyl radicals

Nanoscale ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 4552-4561 ◽  
Author(s):  
Tamra J. Fisher ◽  
Yunyun Zhou ◽  
Tai-Sing Wu ◽  
Meiyu Wang ◽  
Yun-Liang Soo ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Hydroxyl Radicals ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Intrinsic Activity ◽  
Atomic Structures ◽  
Structure Activity ◽  
Nanostructured Ceria ◽  
Ceria Catalysts ◽  
Relationship Of

The morphologies and associated atomic structures of ceria catalysts influence their intrinsic activity towards the catalytic production of hydroxyl radicals from hydrogen peroxide.

scholarly journals Probing the Structure-Activity Relationship of an Antioxidant Tuna-Backbone Derived Peptide

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 398-398
Author(s):  
Varun Gopinatth ◽  
Elaine Ballinger ◽  
Jung Kwon
Keyword(s):  
Antioxidant Activity ◽  
Reactive Oxygen ◽  
Structure Activity Relationship ◽  
Peptide Sequence ◽  
Cellular Damage ◽  
Activity Relationship ◽  
Antioxidant Peptides ◽  
Antioxidant Peptide ◽  
Structure Activity ◽  
Relationship Of

Abstract Objectives DNA is easily degraded by reactive oxygen and nitrogen species, and once damaged can cause significant biological problems. Endogenous mechanisms exist to neutralize reactive oxygen species, but nutritional antioxidants provide extra protection against cellular damage. There is interest in identifying antioxidant peptide nutraceuticals that can provide health benefits when included in diets. Current research identifies antioxidant peptides from natural sources but often stops short of examining mechanisms for activity. An antioxidant peptide (APTBP) was previously characterized from tuna backbone protein. This study investigates the structure-activity relationship of APTBP to identify how the specific peptide sequence contributes to the antioxidant activity. Better understanding of the mechanism of antioxidant peptides can provide insight into future screens and combine with predictive software to identify potential antioxidative sequences from protein sources of interest. Methods Peptide array was synthesized by Thermo Fisher. Modifications were chosen in broad categories with possible mechanistic impact including altering the peptide PI, disrupting the secondary structure, increasing or decreasing hydrophobicity, and increasing aromaticity. The array was tested for activity based on the ability to scavenge ABTS free radical. Results APTBP analogs without hydrophilic, and aromatic residues showed significant loss of activity, up to 76.8%. Notably, substitution of a single tryptophan on either terminal end of the peptide resulted in up to 63.1% increased activity, while substitution of tryptophan on both ends decreased activity by 10.3%. Conclusions The antioxidant activity of APTBP is likely the result of a delicate interplay between amino acids in the peptide, but tryptophan residues had an important impact on activity. Tryptophan has an indole side chain, and is a non-polar, aromatic amino acid. The antioxidant activity of ABTBP is significantly linked to the presence of tryptophan, indicating that aromaticity and electron sharing contributes majorly to the ability of ABTBP to scavenge free radicals. The results from this study can help in future research that aims to identify other potential antioxidant peptides as well as ways to increase antioxidant activity of existing peptides. Funding Sources OSU Honors College.

scholarly journals An Overview of Bioactive Alkaloid, Semi-Synthetic Analogs, Mechanism of Action and Structure-Activity Relationship of Piperine as Antioxidant

2021 ◽  
Vol 33 (9) ◽  
pp. 2244-2250
Author(s):  
Sagar Joshi ◽  
Salahuddin ◽  
Rajnish Kumar ◽  
Divya Sharma
Keyword(s):  
Antioxidant Activity ◽  
Mechanism Of Action ◽  
Structure Activity Relationship ◽  
Black Pepper ◽  
Activity Relationship ◽  
Pharmacological Activities ◽  
Structure Activity ◽  
Natural Alkaloid ◽  
Relationship Of ◽  
Derivatives Of

Piperine, a natural alkaloid obtained from black pepper exhibit a variety of pharmacological activities like antioxidant activity and in this article, the mechanism of the antioxidant, structure-activity relationship of piperine as an antioxidant and various schemes of derivatives of piperine as antioxidants were discussed.

scholarly journals Synthesis, Antioxidant activity and Structure-Activity Relationship of gallic hydrazones Analogues

2021 ◽  
Author(s):  
Zhengrong Wu ◽  
Peng Chen ◽  
Ying-Qian Liu
Keyword(s):  
Antioxidant Activity ◽  
Food Industry ◽  
Hek293 Cell ◽  
Antioxidant Properties ◽  
Positive Control ◽  
Structure Activity ◽  
Anti Oxidant ◽  
Sar Study ◽  
Relationship Of ◽  
Oxidative Agents

Abstract A series of gallic acid hydrazones were designed and synthesized as new potential anti-oxidant agents. Most of these compounds are potent antioxidants. The strongest compounds are 11 and 15 (EC50: 6.42 μg·mL−1, 6.86 μg·mL−1, DPPH) and (EC50: 12.85μg·mL−1, 12.49μg·mL−1ABTS), more potent than the positive control Trolox. Furthermore, the promising compounds 11 and 15 exhibited very low cytotoxic activity against HEK293 cell (IC50 >56.4 µM). The SAR study revealed that the pattern of hydroxyl, methoxy and methyl substituents on the gallic hydrazones framework can increase the antioxidant properties of the prototype compounds. Moreover, the results also showed that the activity increased with the number of the groups and increased following hydroxyl > methoxy > methyl. Overall, the present study suggests that the designed compounds may serve as lead molecules for developing novel anti-oxidative agents in food industry.

Inhibition of Human Cytomegalovirus Proteinase by Salcomine Derivatives

1998 ◽  
Vol 9 (3) ◽  
pp. 269-274 ◽  
Author(s):  
S Watanabe ◽  
K Konno ◽  
S Shigeta ◽  
T Yokota
Keyword(s):  
Human Cytomegalovirus ◽  
Hcmv Infection ◽  
Inhibitory Concentration ◽  
Laboratory Strain ◽  
Serine Proteinases ◽  
Structure Activity ◽  
Hcmv Replication ◽  
Relationship Of ◽  
Related Compounds ◽  
Strain Ad169

Salcomine, N,N'-bis(salicylidene)ethylene diaminocobalt (II), and its derivatives were evaluated for their ability to inhibit selectively human cytomegalovirus (HCMV) proteinase activity. The 50% inhibitory concentration (IC50) of salcomine was 1.4 μM for HCMV proteinase, but >200 μM for three other serine proteinases (trypsin, >250 μM; chymotrypsin, 206 μM; and elastase, >250 μM). Two salcomine derivatives also inhibited HCMV proteinase with IC50 values under 2 μM. Studies of the structure–activity relationship of salcomine-related compounds showed that the phenyl moiety and the spacer moiety (distance betweenthe two amines) were instrumental in the inhibition of HCMV proteinase. Moreover, salcomine inhibited the growth of laboratory strain AD169 and three clinical isolates at a 50% effective concentration (EC50) range of 1.92–2.89 μM. These results show that salcomine derivatives are potent and selective inhibitors of HCMV proteinase and HCMV replication in cell culture. Salcomine derivatives appear to be worth pursuing as candidate drugs for the chemotherapy of HCMV infection.

Synthesis, Antioxidant Activity, and Structure–Activity Relationship of SCAP1 Analogues

2020 ◽  
Author(s):  
Rani Maharani ◽  
Ace Tatang Hidayat ◽  
Irana Rahmawati Sabana ◽  
Anastasya Firdausi ◽  
Alifah Aqmarina ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Structure Activity Relationship ◽  
Activity Relationship ◽  
Structure Activity ◽  
Relationship Of

scholarly journals Synthesis of Steryl Hydroxycinnamates to Enhance Antioxidant Activity of Rapeseed Oil and Emulsions

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4536
Author(s):  
Dobrochna Rabiej-Kozioł ◽  
Marek P. Krzemiński ◽  
Aleksandra Szydłowska-Czerniak
Keyword(s):  
Antioxidant Activity ◽  
Radical Cation ◽  
Rapeseed Oil ◽  
Inhibitory Concentration ◽  
Dpph Radical ◽  
Oxidation Processes ◽  
Steryl Esters ◽  
Chemical Structures ◽  
Potential Applications ◽  
Control Samples

In recent years, steryl esters have found potential applications in food, pharmaceutical and cosmetic industries. Therefore, three hydroxycinnamate steryl esters (HSEs): β-sitosteryl sinapate (β-SSA), β-sitosteryl caffeate (β-SCA), and β-sitosteryl ferulate (β-SFA) were synthesized by chemical approach and their antioxidant activity (AA) were analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. The values of inhibitory concentration (IC50) of each ester needed to inhibit 50% of the DPPH radical (IC50(DPPH) = 238.9, 78.3, 290.0 µmol/L for β-SSA, β-SCA, and β-SFA, respectively) and ABTS radical cation (IC50(ABTS) = 174.6, 106.7, 206.0 µmol/L for β-SSA, β-SCA, and β-SFA, respectively) were estimated and compared with antioxidant potential of phenolic acids. Moreover, the effect of HSEs addition in the concentrations range between 0.01% and 0.5% on the AA of refined rapeseed oil, mayonnaise and margarine was evaluated. Chemical structures of the synthesized HSEs and their concentrations strongly affect the AA of fat products. Oil and emulsions supplemented with higher concentrations of HSEs had significantly higher AA than control samples. Unfortunately, lower concentrations of HSEs (0.01% and 0.02%) did not increase the AA of fat products. However, steryl phenolates added in higher amounts can be considered as potential antioxidants delaying the oxidation processes of studied fats.

scholarly journals Comparison of Antioxidant Properties of a Conjugate of Taxifolin with Glyoxylic Acid and Selected Flavonoids

Antioxidants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1262
Author(s):  
Victoria S. Shubina ◽  
Victoria I. Kozina ◽  
Yuri V. Shatalin
Keyword(s):  
Antioxidant Activity ◽  
Carbonyl Compounds ◽  
Antioxidant Properties ◽  
Glyoxylic Acid ◽  
Binding Ability ◽  
Antioxidant Profile ◽  
Structure Activity ◽  
High Antioxidant Activity ◽  
Lipid Peroxidation Inhibitory Activity ◽  
Relationship Of

It is known that flavonoids can react with toxic carbonyl compounds in the process of the storage, aging, and digestion of flavonoid-rich foods and beverages. However, the effect of these reactions on the antioxidant properties of the polyphenolic fraction and the properties of the resulting products remain poorly studied. The aim of the present work was to study the antioxidant activity of quercetin, taxifolin, catechin, eriodictyol, hesperetin, naringenin and a product of the condensation of taxifolin with glyoxylic acid, as well as to reveal the structure–activity relationship of these polyphenols. It was found that flavonoids containing the catechol moiety exhibited higher antioxidant activity than hesperetin and naringenin. The product showed the highest hydrogen peroxide scavenging activity, a lower metal-reducing and a higher iron-binding ability than catechol-containing flavonoids, and a lipid peroxidation inhibitory activity comparable with that of taxifolin. Thus, the condensation of flavonoids with toxic carbonyl compounds might lead to the formation of products exhibiting high antioxidant activity. Meanwhile, the conditions under which parent flavonoids and their products exhibit the maximal antioxidant activity may differ. The data suggest that the antioxidant profile of the polyphenolic fraction and bioavailability of polyphenols, carbonyl compounds, and metal ions may change when these reactions occur.

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