scholarly journals Functionalization of Betulinic Acid with Polyphenolic Fragments for the Development of New Amphiphilic Antioxidants

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 148
Author(s):  
Joana L. C. Sousa ◽  
Cristiana Gonçalves ◽  
Ricardo M. Ferreira ◽  
Susana M. Cardoso ◽  
Carmen S. R. Freire ◽  
...  
Keyword(s):  
Betulinic Acid ◽  
Aldol Condensation ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Added Value ◽  
Scavenging Effect ◽  
Synthetic Strategy ◽  
Antioxidant Agents ◽  
Radical Scavenging Ability ◽  
Aldol Condensation Reactions

The present work aimed at the valorization of biomass derived compounds by their transformation into new added-value compounds with enhanced antioxidant properties. In this context, betulinic acid (BA) was decorated with polyphenolic fragments, and polyhydroxylated (E)-2-benzylidene-19,28-epoxyoleanane-3,28-diones 4a–d were obtained. For that, the synthetic strategy relied on base-promoted aldol condensation reactions of methyl betulonate, which was previously prepared from natural BA, with appropriate benzaldehydes, followed by cleavage of the methyl protecting groups with BBr3. It is noteworthy that the HBr release during the work-up of the cleavage reactions led to the rearrangement of the lupane-type skeleton of the expected betulonic acid derivatives into oleanane-type compounds 4a–d. The synthesized compounds 4a–d were designed to have specific substitution patterns at C-2 of the triterpene scaffold, allowing the establishment of a structure-activity relationship. The radical scavenging ability of 4a–d was evaluated using the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS•+) scavenging assays. In particular, derivative 4c, bearing a catechol unit, revealed to be the most efficient scavenger against both free radicals DPPH• and ABTS•+. Subsequently, we designed two analogues of the hit derivative 4c in order to achieve more potent antioxidant agents: (i) the first analogue carries an additional unsaturation in its lateral chain at C-2 (analogue 5) and (ii) in the second analogue, E-ring was kept in its open form (analogue 6). It was observed that the presence of an extended π-conjugated system at C-2 contributed to an increased scavenging effect, since analogue 5 was more active than 6, α-tocopherol, and 4c in the ABTS•+ assay.

scholarly journals Synthesis and Antioxidant Properties of Novel 2-(2,4-Dioxothiazolidin-5-ylidene)-Acetamides Containing 1,3,4-Thia/Oxadiazole Moieties

2021 ◽  
Vol 12 (5) ◽  
pp. 6710-6722
Keyword(s):  
Ascorbic Acid ◽  
Acetyl Chloride ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Scavenging Effect ◽  
Highly Active ◽  
Ethanol Medium ◽  
Ic50 Value ◽  
Radical Scavenging Ability

A series of novel 1,3,4-thia(oxa)diazole substituted 2-(2,4-dioxothiazolidine-5-ylidene)-acetamides 3a-c, 4 and 5a-k have been synthesized following the acylation reaction of 2-amino-5-aryl-1,3,4-oxadiazoles, 5-amino-1,3,4-thiadiazole-2-thiol and it’s S-alkylated derivatives with 2-(2,4-dioxothiazolidine-5-ylidene)acetyl chloride in dioxane medium. The functionalization of compounds 3b, 3c, 5d and 5e was carried out on their N3 position under N-alkylation conditions with N-aryl-2-chloroacetamides in DMF/ethanol medium yielded the corresponding 2,4-dioxothiazolidine-3,5-diacetic acid diamides 6a-e and 7a-b. The structures of target compounds were confirmed by using 1H NMR spectroscopy and elemental analysis. The antioxidant activity evaluation in vitro of the synthesized compounds was performed by the method of scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. As a result, the highly active compound 4, namely 2-(2,4-dioxothiazolidin-5-ylidene)-N-(5-mercapto-[1,3,4]thiadiazol-2-yl)acetamide was found to be the most efficient candidate among all compounds with a radical scavenging ability of 88.9%, which was comparable that for ascorbic acid (92.7%). The experimentally calculated IC50 value of 43.1 µM for compound 4 was lower than for ascorbic acid (50.5 µM).

scholarly journals Synthesis of Novel Nitric Oxide Releasing Furoxan Hybrids from Biologically Active Bicyclic Amine and their Antioxidant Activity

2019 ◽  
Vol 31 (8) ◽  
pp. 1724-1728
Author(s):  
P.M. Swami ◽  
P.K. Zubaidha ◽  
G.B. Tiwari
Keyword(s):  
Nitric Oxide ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Biologically Active ◽  
Scavenging Effect ◽  
Antioxidant Agents ◽  
Radical Scavenging Effect ◽  
Nitric Oxide Releasing

The present paper describes the synthesis of novel nitric oxide hybrids obtained by linking bioactive bicyclic amine to substituted furoxans. The antioxidant activities were studied in vitro based on the radical scavenging effect of stable DPPH free radical using ascorbic acid as a standard. The nitric oxide hybrids showed remarkable antioxidant properties and hence, can be employed as potential antioxidant agents.

scholarly journals ANTIDIABETIC AND ANTIOXIDANT ACTIVITIES OF ETHANOLIC EXTRACT OF PIPER BETLE L. LEAVES IN CATFISH, CLARIAS GARIEPINUS

2018 ◽  
Vol 11 (3) ◽  
pp. 194 ◽  
Author(s):  
Kavitha S ◽  
Parthasarathi Perumal
Keyword(s):  
Antioxidant Activities ◽  
Clarias Gariepinus ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Metformin Hydrochloride ◽  
Piper Betle ◽  
Phytochemical Analysis ◽  
Standard Drug ◽  
Antioxidant Agents ◽  
Ic50 Values

 Objective: The present study was undertaken to assess the α-amylase inhibitory activity and antidiabetic experimental catfish model and antioxidant properties of Piper betle L. ethanolic (PBE) extract.Methods: The phytochemical analysis of PBE extract was performed. The PBE extract was tested for their inhibitory effect on the α-amylase assay, which compared to the control, acarbose. The absorbance was read at 540 nm using a spectrophotometer, and IC50 values were calculated. In this present investigation, diabetes mellitus was induced in catfish, Clarias gariepinus by epaxial musculature injection to glucose and standard drug, Metformin hydrochloride. After 24-h incubation, the treated fishes were dissected, and the blood, liver, tissue samples, and epaxial musculature regions were collected. In addition, the antioxidant properties of PBE were determined by 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical scavenging and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging (ABTS) assays.Results: The phytochemical screening of PBE revealed the presence of alkaloid, flavonoids, tannins, phenol, glycosides, sterols, saponins, and quinines. Furthermore, the values of (μg/ml) 3.038 and 7.672 α-amylase enzyme inhibition were excellent activity when compared to the acarbose. Moreover, elevated the glucose level (mg/dl) was estimated in blood 1.9±0.35, liver 0.5±0.25, tissue 0.2±0.25, and epaxial musculature 0.8±0.2 after 24-h incubation. The antioxidant effect of maximum activity was found in PBE; IC50 values (μg/ml) of DPPH and ABTS were 9.362 and 6.606, respectively.Conclusions: These studies might be responsible for the P. betle L. that was used as the new source of antidiabetic and antioxidant agents. 

Peripherally substituted soluble nickel phthalocyanines: Synthesis, characterization, aggregation behavior and antioxidant properties

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1478-1485
Author(s):  
Senem Çolak Yazıcı ◽  
Sibel Kahraman ◽  
Salih Z. Yıldız ◽  
Mahmut D. Yılmaz
Keyword(s):  
Sulfonic Acid ◽  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Scavenging Activity ◽  
The Novel ◽  
Diammonium Salt ◽  
Ft Ir ◽  
Radical Scavenging Ability

Tetra-zwitterionic-substituted nickel(II) phthalocyanine derivatives were newly synthesized starting from nonionic 2(3),9(10),16(17),23(24)-tetrakis-[2-([Formula: see text]-((3-dimethylamino)propyl)carbamate)oxyethyl)phthalocyaninato nickel (II). The novel compounds have been characterized by a combination of UV-vis, FT-IR and mass spectroscopies and elemental analysis. The critical micelle concentrations of the prepared compounds were measured, and the antioxidant activities were analyzed with radical scavenging ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS). The zwitterionic molecules showed aggregated spectra in the UV-vis region, and they might be good surfactant candidates for the detergent industry with their appropriate critical micelle concentration (CMC) properties in water. The compounds exhibited ABTS radical scavenging activity and thus they have antioxidant activity.

scholarly journals Purification and Identification of Antioxidant Alcalase-Derived Peptides from Sheep Plasma Proteins

Antioxidants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 592 ◽  
Author(s):  
Chengli Hou ◽  
Liguo Wu ◽  
Zhenyu Wang ◽  
Elena Saguer ◽  
Dequan Zhang
Keyword(s):  
Liquid Chromatography ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Amino Acid Sequences ◽  
Dpph Radical ◽  
Antioxidant Peptides ◽  
Animal Blood ◽  
Antioxidant Power ◽  
Radical Scavenging Ability ◽  
Dpph Radical Scavenging

In this study, sheep plasma was submitted to Alcalase-hydrolysis and peptides with better antioxidant properties measured through both the ferric-reducing antioxidant power (FRAP) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability assays were isolated and identified. After hydrolysate ultrafiltration and semi-preparative reverse-phase high-performance liquid chromatography, nine fractions (F1–F9) were obtained, with the two first (F1 and F2) showing the greatest antioxidant potential. These two fractions were further separated by the AKTA purifier system to generate four (F1-1–F1-4) and five (F2-1–F2-5) fractions, respectively, with two of them (F1-2 and F2-1) exhibiting appreciable FRAP activity and DPPH radical scavenging ability. Using liquid chromatography-tandem mass spectrometry, three antioxidant peptides were identified. From their amino acid sequences (QTALVELLK, SLHTLFGDELCK, and MPCTEDYLSLILNR), which include amino acids that have been previously reported as key contributors to the peptide antioxidant properties, it can be maintained that they come mainly from serum albumin. These results suggested that the sheep plasma protein can be considered as a good source of antioxidant peptides and bring forth new possibilities for the utilization of animal blood by-products.

scholarly journals Recent Developments in the Functionalization of Betulinic Acid and Its Natural Analogues: A Route to New Bioactive Compounds

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 355 ◽  
Author(s):  
Joana L. C. Sousa ◽  
Carmen S. R. Freire ◽  
Armando J. D. Silvestre ◽  
Artur M. S. Silva
Keyword(s):  
Betulinic Acid ◽  
Antitumor Agents ◽  
Aldol Condensation ◽  
Antimalarial Activity ◽  
Biological Activities ◽  
Chemical Transformations ◽  
Pentacyclic Triterpenoids ◽  
Natural Analogues ◽  
Palladium Catalyzed ◽  
Aldol Condensation Reactions

Betulinic acid (BA) and its natural analogues betulin (BN), betulonic (BoA), and 23-hydroxybetulinic (HBA) acids are lupane-type pentacyclic triterpenoids. They are present in many plants and display important biological activities. This review focuses on the chemical transformations used to functionalize BA/BN/BoA/HBA in order to obtain new derivatives with improved biological activity, covering the period since 2013 to 2018. It is divided by the main chemical transformations reported in the literature, including amination, esterification, alkylation, sulfonation, copper(I)-catalyzed alkyne-azide cycloaddition, palladium-catalyzed cross-coupling, hydroxylation, and aldol condensation reactions. In addition, the synthesis of heterocycle-fused BA/HBA derivatives and polymer‒BA conjugates are also addressed. The new derivatives are mainly used as antitumor agents, but there are other biological applications such as antimalarial activity, drug delivery, bioimaging, among others.

scholarly journals Antioxidant Properties of a Yogurt Beverage Enriched with Salal (Gaultheria shallon) Berries and Blackcurrant (Ribes nigrum) Pomace during Cold Storage

Beverages ◽  
2018 ◽  
Vol 5 (1) ◽  
pp. 2 ◽  
Author(s):  
Vassilios Raikos ◽  
He Ni ◽  
Helen Hayes ◽  
Viren Ranawana
Keyword(s):  
Phenolic Compounds ◽  
Antioxidant Capacity ◽  
Cold Storage ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Total Phenol ◽  
Total Phenol Content ◽  
Anthocyanin Content ◽  
Total Period ◽  
Scavenging Effect

Aqueous extracts (20% w/w) of dried berry fruits and skins were used as sources of phenolic compounds to fortify yogurt beverages. The total phenol and anthocyanin content of the reformulated yogurts were determined, and the antioxidant properties were compared to plain yogurt (C) during storage at 4 °C for a total period of four weeks. Yogurt beverages fortified with salal berry (SB) extracts contained higher amounts of phenolic compounds (>69.9 μg GAE/mL) and anthocyanins (>19.12 mg C3G/L) compared to drinks supplemented with blackcurrant pomace (BC) extract (>50.13 μg GAE/mL and >10.80 mg C3G/L respectively). Storage affected the stability of anthocyanins, whereas total phenol content remained unaffected. Yogurts with SB displayed the highest antioxidant capacity followed by samples with BC, which is attributed to the radical scavenging effect of the bioactive compounds present with antioxidant properties. The antioxidant capacity of the yogurt beverages fortified with fruit extracts was maintained during cold storage. Findings of this study indicate that SB and BC pomace can be used as functional ingredients to increase the antioxidant potential of yogurt beverages.

scholarly journals The study on the antioxidant activity of polysaccharides isolated from Polygonatum odoratum (Mill.) Druce

2020 ◽  
Vol 21 (47) ◽  
pp. 12-18
Author(s):  
Wu Lan Gerile ◽  
Naranchimeg Dorjpalam ◽  
Wanyuan Gui ◽  
Liang Xu ◽  
Jinglin Liu
Keyword(s):  
Lipid Peroxidation ◽  
Superoxide Anion ◽  
Functional Food ◽  
Anion Radical ◽  
Oxygen Free Radicals ◽  
Colorimetric Method ◽  
Radical Scavenging ◽  
Antioxidant Agents ◽  
Radical Scavenging Ability ◽  
Superoxide Anion Radicals

The polysaccharides isolated from Polygonatum odoratum (Mill.) Druce (POPs) by water extraction, after precipitation with ethanol were purified through deproteinization, decolorization, dialysis, and column chromatography leading to a purified polysaccharide (POPs-I) content of 90.7 %. The scavenging of oxygen free radicals and inhibition of lipid peroxidation (LPO) by POPs-I were analyzed using a colorimetric method. The results showed that the hydroxyl radical scavenging ability of the polysaccharides was weaker than that of benzoic acid, but stronger than those of ascorbic acid and mannitol, and that the superoxide anion radical scavenging ability was inferior to those of all three. When the concentration was higher than 1.0 mg/mL, the POPs-I could inhibit LPO by superoxide anion radicals to a certain degree. Therefore, this work suggests that POPs-I are potential antioxidant agents in medicine and functional food.

scholarly journals Free Radical Scavenging and Anti-Inflammatory Activity of Chlorogenic Acid Mediated Silver Nanoparticle

2020 ◽  
pp. 106-112
Author(s):  
Anu Iswarya Jaisankar ◽  
Lakshminarayanan Arivarasu
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Chlorogenic Acid ◽  
Silver Nanoparticle ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Hazardous Substances ◽  
Oxidation Activity ◽  
Antioxidant Agents ◽  
Anti Inflammatory

Introduction: Nanotechnology is a field of research and innovation concerned with building 'things' - generally, materials and devices on the scale of atoms and molecules. It is a booming field of this 21st century. The role of nano technology is becoming very crucial in nearly every aspect of life ranging from cosmetics to advanced bio technological approaches. In recent years, silver nanoparticles have gained considerable attention in the field of medicine. The green synthesis of nanoparticles eliminates the generation and use of hazardous substances and thus sustains non toxicity. Chlorogenic acids are phenolic compounds formed by the esterification of cinnamic acids. They exhibit various pharmacological Properties. Our study deals with the green synthesis of Chlorogenic acid mediated silver nanoparticles and assessment of their anti inflammatory and antioxidant properties.   Aim: The present study aims at assessing the antioxidant and anti inflammatory property of chlorogenic acid mediated silver nanoparticle and investigating the efficacy of Chlorogenic acid mediated Silver nanoparticle. Materials and Methods: The methodology includes Green synthesis of Chlorogenic acid mediated Silver nano particle synthesis followed by tests for Anti inflammation and Anti oxidation. Results: Both the Anti inflammatory and Anti oxidation activity of the chlorogenic acid mediated silver nanoparticle had shown a proportionate increase in activity with increasing concentration of the compound. Conclusion: Chlorogenic acid mediated silver nanoparticles have shown significant anti inflammatory and anti oxidation activity and they are considered as potent anti inflammatory and antioxidant agents.

scholarly journals Chemical Profiles and Anti-termite Activity of Hydrodistillation Residues From Three Aromatic Plants Acclimated in Burkina Faso

2020 ◽  
Vol 12 (8) ◽  
pp. 245
Author(s):  
Assétou Sankara ◽  
Jean Claude W. Ouédraogo ◽  
Luc Pignolet ◽  
Marie-France Thévenon ◽  
Yvonne L. Bonzi-Coulibaly
Keyword(s):  
Bioactive Compounds ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Reticulitermes Flavipes ◽  
Added Value ◽  
Choice Test ◽  
Mentha Piperita ◽  
Aromatic Plants ◽  
Flavonoid Content ◽  
Dried Extract

Distillation process of aromatic plants produces a considerable amount of solid residues, which are rich in secondary metabolites known as bioactive compounds. In this context, residues from hydrodistillation of selected aromatic plants such as Mentha piperita L., Cymbopogon citratus Stapf and Eucalyptus camaldulensis Dehnh, have been studied for their total polyphenol content using Folin-Ciocalteu Reagent (FCR) method, total flavonoid content using aluminium chlorid (AlCl3) and antioxidant properties were determined as DPPH radical-scavenging ability (IC50). The anti-termite activity was evaluated by a direct non-choice test. The higher antioxidant activity (IC50 = 0.20 mg/ml) and polyphenols content (224.32 mg GAE/g of dried extract) were showed with E. camaldulensis aqueous extract. However, M. piperita and C. citratus ethanolic extracts showed higher flavonoid content (190.99 and 185.19 mg QE/g of dried extract). The most active extract against termite Reticulitermes flavipes was E. camaldulensis ethanolic extract presenting toxicity at 5% and 10% w/w as concentrations. All these data showed that strategic extraction of residues from hydrodistillation can provide interesting bioactive compounds as novel anti-termite agents in plants protection and allow to give an added-value to aromatic plants.

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