Screening for Antioxidant Activity: Diphenylpicrylhydrazine (DPPH) Assay

Author(s):  
Momna Rubab ◽  
Ramachandran Chelliah ◽  
Deog-Hwan Oh
2019 ◽  
Vol 15 (4) ◽  
pp. 341-351 ◽  
Author(s):  
Ana P. Bettencourt ◽  
Marián Castro ◽  
João P. Silva ◽  
Francisco Fernandes ◽  
Olga P. Coutinho ◽  
...  

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.


Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1019
Author(s):  
Lucrezia Angeli ◽  
Sebastian Imperiale ◽  
Yubin Ding ◽  
Matteo Scampicchio ◽  
Ksenia Morozova

The 2,2-diphenyl-1-picrylhydrazyl (DPPH•) assay is widely used to determine the antioxidant activity of food products and extracts. However, the common DPPH• protocol uses a two-point measurement and does not give information about the kinetics of the reaction. A novel stoichio-kinetic model applied in this study monitors the consumption of DPPH• by common antioxidants following the second order reaction. The fitting of such decay yields the rate constant k1, which describes the main reaction between antioxidants and DPPH•, and the rate constant k2, which is attributed to a slower side reaction considering the products generated between the transient radicals (AO•) and another molecule of DPPH•. The model was first applied to antioxidant standards. Sinapic acid, Trolox and ascorbic and chlorogenic acids did not show any side reaction. Instead gallic, ferulic and caffeic acids achieved the best fitting with k2. The products of the side reaction for these compounds were confirmed and identified with high-resolution mass spectrometry. Finally, the kinetic model was applied to evaluate the antioxidant activity of eight herbal extracts. This study suggests a new kinetic approach to standardize the common DPPH• assay for the determination of antioxidant activity.


Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4518
Author(s):  
Raquel Sousa ◽  
Artur Figueirinha ◽  
Maria Teresa Batista ◽  
Maria Eugénia Pina

Cymbopogon citratus DC (Stapf.) is a perennial grass and it is distributed around the world. It is used as a condiment for food and beverage flavouring in the form of infusions and decoctions of its dried leaves. Our previous studies have shown antioxidant, anti-inflammatory and gastroprotective activities for the infusion and its phenolic fractions. The aim of the present work was to develop oral dosage forms from a Cymbopogon citratus extract to be used as a functional food with antioxidant properties. Initially, an essential oil-free infusion was prepared, lyophilized and characterized by HPLC-PDA. Total phenols were quantified with the Folin–Ciocalteu method and the antioxidant activity was assessed by DPPH assay. Gelatine capsules containing the extract with different excipients, selected after DSC and IR trials, were prepared. A formulation exhibiting better antioxidant behaviour in a gastric environment was attained. These results suggest that the proposed formulation for this extract could be a valuable antioxidant product and, consequently, make an important contribution to “preventing” and minimizing diseases related to oxidative stress conditions.


Author(s):  
Shaista Amin ◽  
Amrita Parle

Objective: To synthesize benzothiazole derivatives, characterize them by 1HNMR and ATIR techniques and evaluate for their antioxidant activity.Methods: In the present study 12 benzothiazole derivatives were synthesized by reacting 2-chloronitro benzene as the primary reactant with different aromatic aldehydes and benzoic acids. Reactions were monitored using thin layer chromatography technique, and the newly synthesized derivatives were characterized by ATIR and 1HNMR techniques. The antioxidant assay was performed using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) or ABTS method and 2,2-diphenyl-1-picrylhydrazyl or DPPH method.Results: The antioxidant activity was found to be better in ABTS assay than DPPH assay. The compounds showed comparable activity to ascorbic acid at 100µg/ml.Conclusion: It was found that the synthesized benzothiazole derivatives showed significant radical scavenging potential.


2021 ◽  
Vol 21 (1) ◽  
pp. 33
Author(s):  
M. R. Suchitra ◽  
S. Parthasarathy

<em>Saligrama</em> otherwise called <em>Shaligram</em> or <em>Salagrama</em> is a fossilized shell stone usually recovered from the banks of the Gandaki river in Nepal. It is supposed to be a sacred symbol of Hindus. Soaking the stone in water for twenty to thirty minutes and partaking the water was considered to give good health. Hence, we mobilized two stones which were authorized as original by experts. The first one was worshipped for more than 5 years and the other one for two years. The water soaked was around 25 ml which was analysed for antioxidant activity by DPPH assay with plain water without soakage as control. The antioxidant property was significantly found in both the stones with more activity in the stone worshipped for more than 5 years. We did not standardize the volume and the duration of soakage to exact values while it was approximated to around 20 – 30 minutes. We suggest more refined studies with estimation of rare elements needs to be performed to establish the beneficial effects of this sacred <em>saligrama</em> stone.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Fouad A. Ahmed ◽  
Rehab F. M. Ali

Brassicaspecies are very rich in health-promoting phytochemicals, including phenolic compounds, vitamin C, and minerals. The objective of this study was to investigate the effect of different blanching (i.e., water and steam) and cooking (i.e., water boiling, steam boiling, microwaving, and stir-frying) methods on the nutrient components, phytochemical contents (i.e., polyphenols, carotenoids, flavonoid, and ascorbic acid), antioxidant activity measured by DPPH assay, and phenolic profiles of white cauliflower. Results showed that water boiling and water blanching processes had a great effect on the nutrient components and caused significant losses of dry matter, protein, and mineral and phytochemical contents. However, steam treatments (blanching and cooking), stir-frying, and microwaving presented the lowest reductions. Methanolic extract of fresh cauliflower had significantly the highest antioxidant activity (68.91%) followed by the extracts of steam-blanched, steam-boiled, stir-fried, and microwaved cauliflower 61.83%, 59.15%, 58.93%, and 58.24%, respectively. HPLC analysis revealed that the predominant phenolics of raw cauliflower were protocatechuic acid (192.45), quercetin (202.4), pyrogallol (18.9), vanillic acid (11.90), coumaric acid (6.94), and kaempferol (25.91) mg/100 g DW, respectively.


protocols.io ◽  
2021 ◽  
Author(s):  
Adrieli Sachett ◽  
Matheus Gallas-Lopes ◽  
Greicy M ◽  
Ana P ◽  
Angelo Piato

Author(s):  
YUNITRIANTI ◽  
BERNA ELYA ◽  
ARIKADIA NOVIANI

Objective: Prasman (Ayapana triplinervis [Vahl]) is a plant that can eliminate free radicals through its antioxidant effects. However, little research hasbeen conducted to explore the antioxidant activity of the plant.Methods: A. triplinervis (Vahl) leaves, which were determined by the Indonesian Institute of Sciences (LIPI) Bogor, were used in this study. Meanwhile,extraction was performed using n-hexane, ethyl acetate, and methanol as the solvents. Based on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay usinga UV–visible spectrophotometer and based on ferric reducing antioxidant power (FRAP) assay using a microplate reader.Results: Based on the DPPH assay using a UV–visible spectrophotometer, n-hexane, ethyl acetate, and methanol extracts with a final concentrationof 25 μg/mL inhibited DPPH radical production by 38.91, 51.03, and 54.06%, respectively. Using the percent inhibition, the IC50 for the ethyl acetateand methanol extracts were 28.71 and 23.472 μg/mL, respectively. Based on FRAP assay using a microplate reader, the n-hexane, ethyl acetate, andmethanol extracts had ferrous equivalent antioxidant capacity values of 460, 828.99, and 940.22 μmol/g, respectively. The methanol extract had thegreatest antioxidant activity. The ethyl acetate and methanol extracts at the initial concentrations contained total phenol levels of 12.06 and 42.11 mgGAE/g extract, respectively, as well as total flavonoid levels of 3.24 and 3.41 mg QE/g extract, respectively.Conclusion: Based on the determination of phenol and flavonoid levels, the methanol extract had the greatest antioxidant effects.


2014 ◽  
Vol 9 (2) ◽  
pp. 1934578X1400900
Author(s):  
Sabrin R. M. Ibrahim

Re-investigation of the MeOH extract of the seeds of Cucumis melo L. var. reticulatus (Cucurbitaceae) led to the isolation of a new chromone derivative (5,7-dihydroxy-2-[2-(3-methoxy-4-hydroxyphenyl)ethyl]chromone (5) and a triglyceride (1,3-di-(6 Z,9 Z)-docosa-6,9-dienoyl-2-(6 Z) hexacos-6-enoylglycerol (1), together with three known compounds; α-spinasterol (2), stigmasta-7,22,25-trien-3-ol (3), and D:B-friedoolean-5-ene-3-β-ol (4), are reported from this species for the first time. Their structures were determined by extensive 1D (1H, 13C, and DEPT) and 2D (1H-1H COSY, HMQC, and HMBC) NMR and mass spectral measurements. Compound 5 displayed significant cytotoxic activity against L5178Y cells, with an ED50 of 5 μM. The MeOH extract and 5 showed antioxidant activity using the DPPH assay.


2015 ◽  
Vol 177 ◽  
pp. 405 ◽  
Author(s):  
Yolanda Carmona-Jiménez ◽  
M. Valme García-Moreno ◽  
Jose M. Igartuburu ◽  
Carmelo Garcia Barroso

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