Kinetics and Mechanisms of Antioxidant Activity using the DPPH.Free Radical Method

doi:10.1006/fstl.1997.0240

LWT - Food Science and Technology

Volume 30, Issue 6, September 1997, Pages 609-615

https://doi.org/10.1006/fstl.1997.0240 Get rights and content

Abstract

The reaction mechanisms of three antioxidants are proposed in order to explain experimental results obtained from a kinetic study using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH^.) method, previously adapted in our laboratory. In its radical form, DPPH^.shows an absorbance maximum at 515 nm which disappears upon reduction by an antiradical compound. BHT, a synthetic antioxidant, slowly reacts with DPPH^.reaching a steady state within 5 h. This 2.8-stoichiometric complete reaction follows a 1.5-order with respect to DPPH^.and 0.5 to BHT. The kinetic rate constant, k, is estimated to be 5.0 L/(mol·s) at 20 °C and the energy of activation,Ea, is equal to 35 kJ/mol in methanol. Eugenol reacts with DPPH^.reaching a steady state within 2 h. This 1.9-stoichiometric reaction follows a 2-order with respect to both DPPH^.and eugenol, k andEaare estimated to be 5.4 × 10¹⁰L³/(mol³·s) at 20 °C and 30 kJ/mol, respectively. The eugenol mechanism may involve a dimerization between two phenoxyl radicals. The reaction with isoeugenol is rapid and reversible, with a stoichiometry of 1.1. It is first order with respect to isoeugenol with k (direct reaction) equal to 8.9 × 10⁻²s⁻¹at 10 °C. This reaction is consistent with a pseudo-monomolecular mechanism.

References (17)

E.N. Frankel
In search of better methods to evaluate natural antioxidants and oxidative stability in food lipids
Trends in Food Science and Technology
(1993)
W. Brand-Williams et al.
Use of a free radical method to evaluate antioxidant activity
Food Science and Technology
(1995)
M. Namiki
Antioxidants/antimutagens in food
Critical Reviews in Food Science and Nutrition
(1990)
J.L. Lamaison et al.
Teneurs en acide rosmarinique, en dérivés hydroxycinnamiques totaux et activité antioxydante chez les Apiacées, les Borraginacées et les Lamiacées médicinales
Annales Pharmaceutiques Françaises
(1990)
T. Yoshida et al.
Studies on inhibition mechanism of autoxidation by tannins and flavonoids. V. Radical-scavenging effects of tannins and related polyphenols on 1,1-Diphenyl-2-picrylhydrazyl radical
Chemical Pharmaceutical Bulletin
(1989)
J.L. Lamaison et al.
Activités antiradicalairesin vitro
Plantes Médicinales et Phytothérapie
(1988)
J.H. Noggle
Chemical Kinetics
Physical Chemistry
(1985)
B. Fremaux
Eléments de Cinétique et de Catalyse
(1989)

There are more references available in the full text version of this article.

Cited by (1045)

Effects of pretreatment and drying temperatures on physicochemical and antioxidant properties of dried duku (Lansium domesticum)
2024, Measurement: Food
Duku (Lansium domesticum) is a native of Southeast Asia. Duku is a seasonal fruit and highly deteriorated due to high moisture content of more than 80 %, thus difficult to commercialise due to the short shelf life. The transformation of fresh into dried fruit will increase the commercial values as well as be a solution to reduce fruit loss. This study was conducted to evaluate the effects of pretreatments and drying temperatures on physicochemical and antioxidant properties in dried duku fruit. The duku fruits (whole, flesh, peels and seeds) were subjected to pretreatment process with ascorbic acid solution, sodium metabisulfite solution, sodium erythorbate solution and blanching. Then, the samples were dried at 50 °C, 60 °C, 70 °C and 80 °C, respectively. Determination of total phenolic content (TPC) was carried out based on the Folin-Ciocalteau method. The antioxidant activities were evaluated using ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl). The pH values of all parts of duku were decreased as the drying temperature increases. Seed (pretreated with sodium metabisulfite, dried at 80 °C) showed the highest total phenolic content value with 116.84 ± 0.31 mg gallic acid equivalents per g fruit extract (GAE/g), while lowest in flesh (pretreated with ascorbic acid, dried at 50 °C). Seed (pretreated with sodium metabisulfite, dried at 50 °C) has the highest antioxidant capacity with IC₅₀ value of 41.15 µg/ml (ABTS free radical scavenging) and 121.35 µg/ml (DPPH free radical scavenging) compared to other fruit parts, pretreatments and drying temperatures. The findings of this study indicate the potential of all parts of duku fruit as a valuable source of nutrients. Information on the nutritional and antioxidant properties of this Malaysia's seasonal fruit reveals its potential to be commercialized into different food and beverage products.
Assessing the impact of despination and wax application on long-term cold stored cactus pears
2024, Postharvest Biology and Technology
Glochids and spines on cactus pears represent the main constraint that limit cactus pear consumption, thus their elimination is of pivotal importance for commercialization. Their removal causes abrasions and a reduction of epicuticular wax, which increase mass loss and microbiological spoilage. To mitigate the negative impact of glochids removal, in this study, ‘Gialla’ cactus pears of the second bloom, after despination through rotating brushes, were sprayed with two coating materials: Citrashine or Protégé at 33, 50 or 100%. Fruit were then stored at 20 °C for 1 week or at 6 °C for 4 or 8 weeks followed by 3 or 7 d at 20 °C to simulate marketing conditions. Weight loss, overall appearance and decay incidence were significantly higher in despined fruit compared to control fruit and coated fruit. When applied at 33% Protégé coating showed an overall beneficial effect that contributed to reduce mass loss, decay incidence and to improve fruit appearance without affecting chemical or sensory quality. Protégé at 50% and 100% reduced weight loss but resulted phytotoxic and worsened fruit appearance and had a negative impact on the percentage of marketable fruit, besides increasing the degradation of juice chemical compounds and altering sensory attributes. Citrashine had a good impact on preventing decay slowing down mass loss and overall appearance but altered the chemical and the eating quality as Protégé coating when applied at 50% or 100%.However, in fruit directly placed in simulated marketing conditions at 20 °C, despination neither altered fruit quality nor reduced fruit marketability. Thus, replacement of epicuticular waxes lost by despination with coatings can be beneficial for long term storage of cactus pear, provided that the applied material is not phytotoxic and does not impair the fruit gas exchange.
Elucidating the effect of nixtamalization on the functional, nutritional, and microstructure properties of pearl millet flour
2024, Journal of Cereal Science
The study examined the impact of lime treatment (nixtamalization process) on the functional, proximate, and crystallinity properties of pearl millet flour by cooking them in a 2% calcium hydroxide (Ca (OH)₂) at 75 ± 5 °C for 30 min and then steeping for 4 h. The millets were then milled to produce two types of flour, dry milled nixtamalized flour (DMNF) and wet milled nixtamalized flour (WMNF) and compared with the untreated pearl millet flour (PMF). Nixtamalized samples yielded a flour that contained significantly (p < 0.05) higher content of ash, soluble and insoluble fiber, minerals such as calcium, iron, magnesium, and sodium. Solubility increased with temperature from 30 °C to 90 °C for DMNF (71.86%), WMNF (50%), and for PMF (66.25%) respectively. Shelf-life studies revealed that, the Free Fatty Acid (FFA) content increased from 2.49% to 6.48% for DMNF and from 5.22% to 14.89% for WMNF, with an overall increase of 61.57% for DMNF and 64.94% for WMNF. X-ray diffractogram, of the flour revealed peaks moved towards higher theta values, leading to a reduction in the distance between the planes, consequently reducing the size of crystals. Breakdown of these molecules leads to a disruption/reorientation of the crystalline double-helix pairs, thus reducing crystallinity in nixtamalized samples.
Plant-mediated synthesis of thermally stable metal-polystyrene nanocomposites for antioxidant and antibacterial food packaging
2024, Industrial Crops and Products
Annually, millions of individuals are hospitalized worldwide because of illnesses attributed to foodborne pathogens. With the surge in foodborne diseases, the importance of reliable and optimized food packaging has become more crucial than ever. Okra (Abelmoschus esculentus) seed extract was utilized as a mediator for synthesizing thermally stable nanoparticles (NPs) of Fe⁰, Zn⁰, Ag⁰, Fe₂O₃, ZnO, and Ag₂O. These NPs were subsequently incorporated into polystyrene (PS) sheets to fabricate NPs-PS composites. Nanoparticle synthesis with a uniform morphology and size range of 20–60 nm was confirmed through various characterization techniques, including surface plasmon resonance, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray (EDX) techniques. The antioxidant potential, as determined by the 2,2-diphenylpicrylhydrazyl (DPPH) free radical scavenging and Phosphomolybdenum assay, followed the order of Silver > Iron > Zinc. Conversely, the antimicrobial potential, evaluated through the agar well diffusion method, was in the order of Silver ≈ Zinc > Iron. Zero-valent metal NPs and NPs-PS Composites exhibited superior results compared to metal oxide NPs and NPs-PS Composites. Lemon and Apple slices wrapped in NPs-PS composite sheets exhibited significantly improved shelf life compared to pure PS, demonstrating the high effectiveness of metal NPs modified composites for food packaging by protecting it from oxidative decay and microorganisms.
Synthesis and biological evaluation of selenopyrimidine derivatives bearing thiazolyl moiety
2024, Journal of Saudi Chemical Society
The aim of this study is to explain how new thiazole and selenophene moieties were obtained from 2-amino-4-(4-methylthiazol-2-yl)selenophene-3-carbonitrile (3) and to assess the antioxidant and cytotoxic properties of these new compounds. Compound 3 is prepared and subjected to react with each of CS₂, malononitrile in EtOH/TEA, ECA, a mixture of HCl and AcOH, formamide, formic acid, malononitrile in the presence of EtONa to give their corresponding selenopyrimidine and selenopyridine derivatives 4–10. Moreover, compound 3 reacted with thiourea, hydrazine hydrate, CS₂ in NaOH/DMF, and phenyl isothiocyanate to afford selenolo[2,3-d]pyrimidines 11–17 and related compounds. The recently synthesized compounds were tested for their DPPH radical scavenging and cytotoxic properties against the HePG-2 and MCF-7 cell lines. Compounds 5 and 11 demonstrated potential radical scavenging activity, but compounds 5 and 6 exhibited the strongest cytotoxic action against the examined cell lines. According to molecular docking data, the compounds under research are intriguing candidates for the development of new anticancer therapeutic targets.
κ-Carrageenan/poly(vinyl alcohol) functionalized films with gallic acid and stabilized with metallic ions
2023, International Journal of Biological Macromolecules
Given the environmental issues caused by the extensive use of conventional petroleum-based packaging, this work proposes functional films based on commercial κ-carrageenan (κc), poly(vinyl alcohol) (PVA), and gallic acid (GA) prepared by the “casting” method. Metallic ions in the κc composition stabilized the films, supporting processability and suitable mechanical properties. However, the incorporated GA amount (6.25 and 10 wt%) in the films created from an aqueous κc solution at 3.0 % wt/v (κc3) prevented crystalline domains in the resulting materials. The κc3/GA6.25 and κc3/GA10 films had less tensile strength (8.50 ± 0.61 and 10.28 ± 0.65 MPa) and high elongation at break (2.36 ± 0.16 and 1.19 ± 0.17 %) compared to the other samples, respectively. Low κc contents (κc2.5/GA6.25 and κc2.5/GA10) promoted stiff films and less permeability to water vapor (5.36 ± 0.51 and 3.76 ± 0.02 [×10⁻¹² g(Pa × m × s)⁻¹], respectively. The κc/GA weight ratio also influenced the film wettability, indicating water contact angles (WCAs) between 55 and 74°. The surface wettability implies a low oil permeability and high water swelling capacity of up to 1600 %. The κc/GA also played an essential role in the film's antimicrobial action against Staphylococcus aureus and Escherichia coli. Thus, the κc3/GA10 film showed suitable physical, chemical, and biological properties, having the potential to be applied as food coatings.

View all citing articles on Scopus

^☆: Noggle, J. H.

^f1: To whom correspondence should be addressed.

View full text

Regular ArticleKinetics and Mechanisms of Antioxidant Activity using the DPPH.Free Radical Method☆

Abstract

Trends in Food Science and Technology

Food Science and Technology

Antioxidants/antimutagens in food

Critical Reviews in Food Science and Nutrition

Teneurs en acide rosmarinique, en dérivés hydroxycinnamiques totaux et activité antioxydante chez les Apiacées, les Borraginacées et les Lamiacées médicinales

Annales Pharmaceutiques Françaises

Studies on inhibition mechanism of autoxidation by tannins and flavonoids. V. Radical-scavenging effects of tannins and related polyphenols on 1,1-Diphenyl-2-picrylhydrazyl radical

Chemical Pharmaceutical Bulletin

Activités antiradicalairesin vitro

Plantes Médicinales et Phytothérapie

Chemical Kinetics

Physical Chemistry

Eléments de Cinétique et de Catalyse

Regular Article
Kinetics and Mechanisms of Antioxidant Activity using the DPPH^.Free Radical Method☆