scholarly journals Antioxidant and Antidiabetic Effects of Flavonoids: A Structure-Activity Relationship Based Study

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Murni Nazira Sarian ◽  
Qamar Uddin Ahmed ◽  
Siti Zaiton Mat So’ad ◽  
Alhassan Muhammad Alhassan ◽  
Suganya Murugesu ◽  
...  

The best described pharmacological property of flavonoids is their capacity to act as potent antioxidant that has been reported to play an important role in the alleviation of diabetes mellitus. Flavonoids biochemical properties are structure dependent; however, they are yet to be thoroughly understood. Hence, the main aim of this work was to investigate the antioxidant and antidiabetic properties of some structurally related flavonoids to identify key positions responsible, their correlation, and the effect of methylation and acetylation on the same properties. Antioxidant potential was evaluated through dot blot, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ABTS+radical scavenging, ferric reducing antioxidant power (FRAP), and xanthine oxidase inhibitory (XOI) assays. Antidiabetic effect was investigated throughα-glucosidase and dipeptidyl peptidase-4 (DPP-4) assays. Results showed that the total number and the configuration of hydroxyl groups played an important role in regulating antioxidant and antidiabetic properties in scavenging DPPH radical, ABTS+radical, and FRAP assays and improved bothα-glucosidase and DPP-4 activities. Presence of C-2-C-3 double bond and C-4 ketonic group are two essential structural features in the bioactivity of flavonoids especially for antidiabetic property. Methylation and acetylation of hydroxyl groups were found to diminish thein vitroantioxidant and antidiabetic properties of the flavonoids.

Botanica ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 76-87
Author(s):  
Aziza Lfitat ◽  
Hind Zejli ◽  
Abdelkamel Bousselham ◽  
Yassine El Atki ◽  
Badiaa Lyoussi ◽  
...  

AbstractWe conducted this study to determine and compare the content of phenolic compounds and flavonoids in the argan and olive leaves as well as their antioxidant capacity in aqueous, methanolic, and ethyl acetate extracted fractions. In vitro antioxidant activity was evaluated in comparison with synthetic antioxidants by assessing DPPH• radical scavenging capacity, ferric reducing antioxidant power, scavenging ability by inhibiting the β-carotene/linoleic acid emulsion oxidation, and by the ABTS radical scavenging activity assay. Total phenolic content in argan samples ranged from 221.69 ± 2.07 to 1.32 ± 0.01 mg GAE/g DW and in olive samples from 144.61 ± 0.82 to 1.21 ± 0.02 mg GAE/g DW. Total flavonoids content in argan samples varied from 267.37 ± 1.12 to 25.48 ± 0.02 mg QE/g DW, while in olives from 96.06 ± 0.78 to 10.63 ± 0.05 mg QE/g DW. In vitro antioxidant studies strongly confirmed the antioxidant potency of argan and olive leaves and their richness in secondary metabolites that are effective in free radicals scavenging and metal chelating capacities, indicating their antioxidant power.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Herath Pathiranage Thathmi Wathsara ◽  
Hasitha Dhananjaya Weeratunge ◽  
Mohamed Naeem Ahammadu Mubarak ◽  
Pahan Indika Godakumbura ◽  
Pathmasiri Ranasinghe

Syzygium caryophyllatum L. Alston (Family: Myrtaceae, Sinhala: Heendan) is a red-listed plant that has been used in traditional medicine in Sri Lanka for the treatment of diabetes, but it is yet to be exploited for its potential uses as a functional food or a source of supplements. The present study focused on the evaluation of antidiabetic property of S. caryophyllatum fruits and leaves assessing antioxidant, antiglycation, and antiamylase activities and functional mineral element composition. The crude extracts (CR) of leaves and fruits were fractionated into hexane (Hex) ethyl acetate (EA) and aqueous (AQ) and evaluated for bioactivities along with the crude extracts. The isolated fraction (C3) of Hex fraction of fruit showed significantly high (p<0.05) antiamylase activity with IC50 value 2.27 ± 1.81 μg/mL where the Hex fraction of fruits exhibited the IC50 value as 47.20 ± 0.3 μg/mL which was higher than acarbose (IC50: 87.96 ± 1.43 μg/mL). The EA fraction of leaves showed highest values for DPPH radical scavenging activity, ferric reducing antioxidant power, and oxygen radical absorbance capacity. Significantly high (p<0.05) ABTS radical scavenging activity and iron chelating activity were observed in Hex fraction of fruit. The composition of volatiles in leaf oil was studied with GC-MS, and 58 compounds were identified. Inductively coupled plasma-mass spectrometry data revealed the presence of biologically significant trace elements such as Fe, Zn, Mg, Cu, Se, and Sr in leaves and fruits. It is concluded that the Hex fraction of S. caryophyllatum fruits will be a good source for the formulation of supplements for diabetic management with further evaluation of potency and efficacy.


Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5295
Author(s):  
Xinyu Zhao ◽  
Ruyi Chen ◽  
Yueyue Shi ◽  
Xiaoxi Zhang ◽  
Chongmei Tian ◽  
...  

This study aimed to isolate, prepare and identify the main flavonoids from a standardized Smilax glabra flavonoids extract (SGF) using preparative HPLC, MS, 1H NMR and 13C NMR, determine the contents of these flavonoids using UPLC, then compare their pharmacological activities in vitro. We obtained six flavonoids from SGF: astilbin (18.10%), neoastilbin (11.04%), isoastilbin (5.03%), neoisoastilbin (4.09%), engeletin (2.58%) and (−)-epicatechin (1.77%). The antioxidant activity of six flavonoids were evaluated by determining the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2′-Azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS+) radical scavenging activity and ferric reducing antioxidant power (FRAP). In addition, the anti-inflammatory activity of six flavonoids were evaluated by determining the production of cytokines (IL-1β, IL-6), nitric oxide (NO) using enzyme linked immunosorbent assay and the NF-κB p65 expression using Western blotting in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The results showed that (−)-epicatechin, astilbin, neoastilbin, isoastilbin and neoisoastilbin had strong antioxidant activities, not only in DPPH and ABTS+ radicals scavenging capacities, but in FRAP system. Furthermore, all the six flavonoids could significantly inhibit the secretion of IL-1β, IL-6, NO (p < 0.01) and the protein expression of NF-κB p-p65 (p < 0.01) in LPS-stimulated RAW264.7 cells. This study preliminarily verified the antioxidant and anti-inflammatory activities of six flavonoids in S. glabra.


2015 ◽  
Vol 10 (1) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Farukh S. Sharopov ◽  
Michael Wink ◽  
William N. Setzer

The antioxidant activities of eighteen different essential oil components have been determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay, the 2,2 ’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation assay, and the ferric reducing antioxidant power (FRAP) assay. The phenolic compounds, carvacrol, thymol, and eugenol, showed the best antioxidant activities, while camphor, menthol, and menthone were the least active. The structural and electronic properties of the essential oil components were assessed using density functional theory (DFT) at the B3LYP/6-311++G** level. Correlations between calculated electronic properties and antioxidant activities were generally poor, but bond-dissociation energies (BDEs) seem to correlate with DPPH radical-scavenging activities, and the ferric reducing antioxidant power (FRAP) assay correlated with vertical ionization potentials calculated at the Hartree-Fock/6-311++G** level.


Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3088
Author(s):  
Maciej Spiegel ◽  
Karina Kapusta ◽  
Wojciech Kołodziejczyk ◽  
Julia Saloni ◽  
Beata Żbikowska ◽  
...  

Phenolic acids are naturally occurring compounds that are known for their antioxidant and antiradical activity. We present experimental and theoretical studies on the antioxidant potential of the set of 22 phenolic acids with different models of hydroxylation and methoxylation of aromatic rings. Ferric reducing antioxidant power assay was used to evaluate this property. 2,3-dihydroxybenzoic acid was found to be the strongest antioxidant, while mono hydroxylated and methoxylated structures had the lowest activities. A comprehensive structure–activity investigation with density functional theory methods elucidated the influence of compounds topology, resonance stabilization, and intramolecular hydrogen bonding on the exhibited activity. The key factor was found to be a presence of two or more hydroxyl groups being located in ortho or para position to each other. Finally, the quantitative structure–activity relationship approach was used to build a multiple linear regression model describing the dependence of antioxidant activity on structure of compounds, using features exclusively related to their topology. Coefficients of determination for training set and for the test set equaled 0.9918 and 0.9993 respectively, and Q2 value for leave-one-out was 0.9716. In addition, the presented model was used to predict activities of phenolic acids that haven’t been tested here experimentally.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Mayron Alves Vasconcelos ◽  
Francisco Vassiliepe Sousa Arruda ◽  
Daniel Barroso de Alencar ◽  
Silvana Saker-Sampaio ◽  
Maria Rose Jane Ribeiro Albuquerque ◽  
...  

This study evaluated the effect of derriobtusone A, a flavonoid isolated fromLonchocarpus obtusus, on two important pathogenic bacteria,Staphylococcus aureusandEscherichia coli, as well as its antioxidant activity and toxicity. Planktonic growth assays were performed, and the inhibition of biofilm formation was evaluated. In addition, antioxidant activity was assessed by DPPH radical scavenging assay, ferrous ion chelating assay, ferric-reducing antioxidant power assay, andβ-carotene bleaching assay. Toxicity was evaluated by the brine shrimp lethality test. Results showed that derriobtusone A completely inhibited the planktonic growth ofS. aureusat 250 and 500 μg/mL; however, it did not have the same activity onE. coli. Derriobtusone A reduced the biomass and colony-forming unit (cfu) ofS. aureusbiofilm at concentrations of 250 and 500 μg/mL. In various concentrations, it reduced the biofilm biomass ofE. coli, and, in all concentrations, it weakly reduced the cfu. Derriobtusone A showed highly efficient antioxidant ability in scavenging DPPH radical and inhibitingβ-carotene oxidation. The compound showed no lethality toArtemiasp. nauplii. In conclusion, derriobtusone A may be an effective molecule againstS. aureusand its biofilm, as well as a potential antioxidant compound with no toxicity.


Author(s):  
SURACHAI TECHAOEI ◽  
KHEMJIRA JARMKOM ◽  
THISAKORN DUMRONGPHUTTIDACHA ◽  
WARACHATE KHOBJAI

Objective: This research is to study the production of natural red pigment by Monascus purpureus TISTR3615 in the submerged and solid-statefermentation system using Pathumthani-1 rice as a carbon source.Methods: The antioxidant activity of the red pigment was evaluated in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH), ABTS radical scavenging assay,and ferric-reducing antioxidant power (FRAP) assay, including total phenolic compound.Results and Discussion: The maximum of red pigment production was 0.55±0.02/ml (OD 680 nm) after incubation at 30°C for 24 days. Theantioxidant activity based on inhibition DPPH (%), ABTS radical scavenging activity (%), and FRAP activity (mM Fe2+/g) was 97.80±1.51,68.64±0.46, and 0.32±0.021, respectively. The total phenolic content was 164.78±2.82 μg GAE/mg.Conclusion: It was estimated that Monascus pigments, leading to nutraceutical and pharmaceutical applications, cosmetic industry, and foodindustry.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Beatrice Muthoni Guchu ◽  
Alex King’ori Machocho ◽  
Stephen Kiruthi Mwihia ◽  
Mathew Piero Ngugi

Oxidative stress is the result of the disparity between pro-oxidants and antioxidants in an organism, and it is important in the pathogenesis of several degenerative disorders, such as arthritis, Alzheimer’s, cancer, and cardiovascular diseases. Free radicals can damage biomolecules, such as nucleic acids, lipids, proteins, polyunsaturated fatty acids, and carbohydrates, and the DNA leading to mutations. The use of antioxidants is effective in delaying the oxidation of biomolecules. Antioxidants are complexes found in the food that can retard or deter oxidation by preventing the initiation and propagation of oxidizing chain reactions. Medicinal plants have been used for centuries by man to manage diseases and have a host of antioxidant complexes. Traditionally, Caesalpinia volkensii, Vernonia lasiopus, and Acacia hockii have folkloric remedies against associated oxidative stress-mediated complications. However, the upsurge in its use has not been accompanied by scientific validations to support these claims. In this study, in vitro antioxidant activity of Caesalpinia volkensii, Vernonia lasiopus, and Acacia hockii collected from Embu County (Kenya) were determined by radical scavenging activities of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical in addition to ferric reducing antioxidant power analyzed against that of L-ascorbic acid as the standard. The obtained results revealed remarkable antioxidant activities of the studied plant extracts as evidenced by the low IC50 and EC50 values. These antioxidant activities could be due to the presence of antioxidants phytochemicals such as flavonoids, phenols, terpenoids, and saponins among others. Therefore, the therapeutic potential of this plant could be due to their antioxidant properties. This study recommends bioassay of the extracts against oxidative stress-related disorders for development of phytomedicine with antioxidant properties.


Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5747
Author(s):  
Ricardo Guzmán-Ávila ◽  
Mayra Avelar ◽  
Edgar A. Márquez ◽  
Julio C. Rivera-Leyva ◽  
José R. Mora ◽  
...  

Dapsone (DDS) is an antibacterial drug with well-known antioxidant properties. However, the antioxidant behavior of its derivatives has not been well explored. In the present work, the antioxidant activity of 10 dapsone derivatives 4-substituted was determined by an evaluation in two in vitro models (DPPH radical scavenging assay and ferric reducing antioxidant power). These imine derivatives 1–10 were obtained through condensation between DDS and the corresponding aromatic aldehydes 4-substuited. Three derivatives presented better results than DDS in the determination of DPPH (2, 9, and 10). Likewise, we have three compounds with better reducing activity than dapsone (4, 9, and 10). In order to be more insight, the redox process, a conceptual DFT analysis was carried out. Molecular descriptors such as electronic distribution, the total charge accepting/donating capacity (I/A), and the partial charge accepting/donating capacity (ω+/ω−) were calculated to analyze the relative donor-acceptor capacity through employing a donor acceptor map (DAM). The DFT calculation allowed us to establish a relationship between GAPHOMO-LUMO and DAM with the observed antioxidant effects. According to the results, we concluded that compounds 2 and 3 have the lowest Ra values, representing a good antioxidant behavior observed experimentally in DPPH radical capturing. On the other hand, derivatives 4, 9, and 10 display the best reducing capacity activity with the highest ω− and Rd values. Consequently, we propose these compounds as the best antireductants in our DDS imine derivative series.


2019 ◽  
Vol 15 (7) ◽  
pp. 700-706
Author(s):  
Mehdi Zarei ◽  
Ali Fazlara ◽  
Maedeh S. Hamedani

Background: All over the world, the quality of commercial honeys varies greatly depending on many factors. Hence, this study was conducted to evaluate the physicochemical and antioxidant properties of Iranian commercial honeys to confirm their nutritional and economical quality. Methods: Fifty three honey samples from six different types, including alfalfa, milkvetch, lotus, thyme, coriander and multifloral honeys, were analyzed for pH, free acidity, electrical conductivity, Ash, moisture, hydroxymethylfurfural, reducing sugars, glucose, fructose, proline, color, total phenolic content, ferric reducing antioxidant power and DPPH radical-scavenging activity. Results: : In total, physicochemical properties of different honey types were in the range of 4.3 ± 0.49 to 5.2 ± 0.49 for pH, 13.81 ± 2.5 to 26.22 ± 2.8 for free acidity (meq/kg), 15.95 ± 0.45 to 17.98 ± 0.97 for moisture (%), 282.2 ± 50.3 to 578 ± 47 for electrical conductivity (µS/cm), 0.14 ± 0.04 to 0.38 ± 0.03 for ash (g/100 g), 68.66 ± 4.3 to 72.09 ± 6.4 for reducing sugars (g/100 g), 34.67 ± 2.6 to 36.7 ± 2.2 for glucose (g/100 g), 31.9 ± 4.75 to 37.04 ± 4.0 for fructose (g/100 g), 6.1 ± 5.8 to 22.85 ± 10.9 for hydroxymethylfurfural (mg/kg), 426.7 ± 53.91 to 593.9 ± 108.6 for proline (mg/kg), 46.27 ± 4.3 to 96.04 ± 14.4 for color (mm) and 245.4 ± 48.45 to 573.9 ± 69.3 for total phenolic (mg/kg) content. In terms of antioxidant capacity, lotus and thyme honeys were preferable, while the highest level of DPPH radical scavenging activity and ferric reducing antioxidant power were observed in lotus and thyme honeys. Conclusion: These results confirmed that the Iranian commercial honeys meet the quality standards established by national and international regulatory agencies.


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