scholarly journals Antioxidant activity of acerola extracts

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S155-S158 ◽  
Author(s):  
I. Nagamine ◽  
H. Sakurai ◽  
H. T T Nguyen ◽  
M. Miyahara ◽  
J. Parkányiová ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Linoleic Acid ◽  
Ferulic Acid ◽  
Phenolic Antioxidants ◽  
Zeroth Order ◽  
The Stability ◽  
In The Beginning ◽  
Β Carotene

West Indian cherries or acerola fruits (Malpighia glabra L.) are very rich in ascorbic acid, and also contain flavonoids and anthocyanins. Therefore, their antioxidant activity is interesting. Aqueous and methanolic acerola extracts increased the stability of β-carotene-linoleic acid emulsions against oxidation. Flavonoids and anthocyanins obviously enhanced the effect of ascorbic acid. The effect of natural acerola antioxidants was comparable to that of phenolic antioxidants, such as ferulic acid. During the determination of antioxidant activity in emulsions, carotene was destroyed following a complex kinetics in the beginning of oxidation, but the zeroth order kinetics in later stages of oxidation.

scholarly journals Complexes of Copper and Iron with Pyridoxamine, Ascorbic Acid, and a Model Amadori Compound: Exploring Pyridoxamine’s Secondary Antioxidant Activity

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 208
Author(s):  
Guillermo García-Díez ◽  
Roger Monreal-Corona ◽  
Nelaine Mora-Diez
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Rate Constant ◽  
Stable Complex ◽  
Aqueous Environment ◽  
Oh Radicals ◽  
Bidentate Ligands ◽  
Superoxide Radical Anion ◽  
Amadori Compound ◽  
The Stability

The thermodynamic stability of 11 complexes of Cu(II) and 26 complexes of Fe(III) is studied, comprising the ligands pyridoxamine (PM), ascorbic acid (ASC), and a model Amadori compound (AMD). In addition, the secondary antioxidant activity of PM is analyzed when chelating both Cu(II) and Fe(III), relative to the rate constant of the first step of the Haber-Weiss cycle, in the presence of the superoxide radical anion (O2•−) or ascorbate (ASC−). Calculations are performed at the M05(SMD)/6-311+G(d,p) level of theory. The aqueous environment is modeled by making use of the SMD solvation method in all calculations. This level of theory accurately reproduces the experimental data available. When put in perspective with the stability of various complexes of aminoguanidine (AG) (which we have previously studied), the following stability trends can be found for the Cu(II) and Fe(III) complexes, respectively: ASC < AG < AMD < PM and AG < ASC < AMD < PM. The most stable complex of Cu(II) with PM (with two bidentate ligands) presents a ΔGf0 value of −35.8 kcal/mol, whereas the Fe(III) complex with the highest stability (with three bidentate ligands) possesses a ΔGf0 of −58.9 kcal/mol. These complexes can significantly reduce the rate constant of the first step of the Haber-Weiss cycle with both O2•− and ASC−. In the case of the copper-containing reaction, the rates are reduced up to 9.70 × 103 and 4.09 × 1013 times, respectively. With iron, the rates become 1.78 × 103 and 4.45 × 1015 times smaller, respectively. Thus, PM presents significant secondary antioxidant activity since it is able to inhibit the production of ·OH radicals. This work concludes a series of studies on secondary antioxidant activity and allows potentially new glycation inhibitors to be investigated and compared relative to both PM and AG.

In Vitro Antioxidant Activity Metaplexis Japonica Makino Extract and Derivatives

2014 ◽  
Vol 955-959 ◽  
pp. 387-389 ◽  
Author(s):  
Bao Qing Wang
Keyword(s):  
Antioxidant Activity ◽  
Linoleic Acid ◽  
Ethyl Acetate ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Acid Test ◽  
Acetone Extracts ◽  
Β Carotene ◽  
Ethyl Acetate Extracts

Antioxidant activities of acetone and ethyl acetate extracts from Metaplexis japonica Makino, one of famous medicine plants in the eastnorth region of China, named luomo in Chinese, were examined by a DPPH (1,1-Diphenyl-2-picrylhydrazyl) radical-scavenging assay and a β-carotene-linoleic acid test. In DPPH, the antioxidant activity of the acetone extracts, ethyl acetate extracts and derivative were IC50 were 313.21, 266.92 and 118.78μg/mL, respectively. In the β-carotene-linoleic acid test, IC50 were 285.09, 351.57 and 123.89μg/mL. It was concluded that Metaplexis japonica Makino and its derivatives might be a potential natural source of antioxidants .

scholarly journals Implications for Degenerative Disorders: Antioxidative Activity, Total Phenols, Flavonoids, Ascorbic Acid, β-Carotene and β-Tocopherol inAloe vera

2009 ◽  
Vol 2 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Nurten Ozsoy ◽  
Eda Candoken ◽  
Nuriye Akev
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Biological Effects ◽  
Aloe Vera ◽  
Total Phenols ◽  
Beneficial Effects ◽  
Degenerative Disorders ◽  
Phosphatidylcholine Liposome ◽  
Aqueous Leaf Extract ◽  
Β Carotene

In order to demonstrate whether the known biological effects ofAloe vera(L.) Burm. fil. could correlate with the antioxidant activity of the plant, the antioxidant activity of the aqueous leaf extract was investigated. The present study demonstrated that the aqueous extract fromA. veraleaves contained naturally occuring antioxidant components, including total phenols, flavonoids, ascorbic acid, β-carotene and α-tocopherol. The extract exhibited inhibitory capacity against Fe3+/ascorbic acid induced phosphatidylcholine liposome oxidation, scavenged stable DPPH•, ABTS•+and superoxide anion radicals, and acted as reductant. In contrast, the leaf inner gel did not show any antioxidant activity. It was concluded that the known beneficial effects ofAloe veracould be attributed to its antioxidant activity and could be related to the presence of phenolic compounds and antioxidant vitamins.

scholarly journals Biflavonoids from the Unripe Fruits of Clusia Paralicola and their Antioxidant Activity

2012 ◽  
Vol 7 (12) ◽  
pp. 1934578X1200701 ◽  
Author(s):  
Rafaela Ferreira Oliveira ◽  
Celso Amorim Camara ◽  
Maria de Fátima Agra ◽  
Tania Maria Sarmento Silva
Keyword(s):  
Antioxidant Activity ◽  
Linoleic Acid ◽  
Spectral Data ◽  
2D Nmr ◽  
Cd Spectra ◽  
Total Extract ◽  
Isolation And Characterization ◽  
Β Carotene ◽  
Unripe Fruits

Investigation of the green fruits of Clusia paralicola (Clusiaceae) led to the isolation and characterization of two 3,8″-biflavonoids, 2R, 3S, 2″R, 3″R-GB1-7″- O-β-glucoside (1) and 2R, 3S, 2″R, 3,8″-binaringenin-7″-O-β-glucoside (2), together with four known compounds: β-sitosterol, stigmasterol, β-amyrin, and epicatechin. The structures were established from the IR, LC-ESI-MS and NMR spectral data, including 2D-NMR experiments. The absolute configurations of 1 and 2 were determined by CD spectra. The total extract and the biflavonoids demonstrated significant antioxidant activity in DPPH, ABTS, and β-carotene/linoleic acid tests.

scholarly journals ANTIOXIDANT ACTIVITY DURING STORAGE OF APPLES SUBJECTED TO IRRADIATION

2015 ◽  
Vol 39 (3) ◽  
pp. 269-275 ◽  
Author(s):  
Camila Argenta Fante ◽  
Heloísa Helena de Siqueira Elias ◽  
Paôla de Castro Henrique ◽  
Ana Carolina Vilas Boas ◽  
Luiz Carlos de Oliveira Lima
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Soluble Solids ◽  
Antioxidant Compounds ◽  
Post Harvest ◽  
Apple Cultivars ◽  
Solids Content ◽  
Physical And Chemical ◽  
Β Carotene ◽  
Low Irradiation

Nowadays, the number of studies about fruit conservation as well as the benefits of consumption of foods rich in antioxidant compounds was increased. This study aimed to quantify antioxidant compounds and their activity and to evaluate the physical and chemical changes during the post-harvest storage of Eva's apple cultivars that were subjected to gamma irradiation at doses of 0; 0.5; 1.0 and 1.5 kGy. The antioxidant activity was measured by the 2.2-diphenyl-1-picrylhydrazyl (DPPH) and the β-carotene/linolenic acid methods. Levels of total phenolics, ascorbic acid, color, and soluble solids were evaluated. The results showed that, regardless of the irradiation dose, there was an increase in % SRL during post-harvest storage of Eva's apples. Low irradiation doses were able to preserve the phenolic compounds, maintain the ascorbic acid levels and avoid an increase in the soluble solids content.

scholarly journals Selective Determination of Dopamine in Presence of Ascorbic Acid Using Nafion Coated Methylene Blue Functionalized Graphite Electrode

2019 ◽  
Vol 31 (10) ◽  
pp. 2185-2190
Author(s):  
G. Sivasankari ◽  
K. Sivasankari ◽  
T. Nalini ◽  
P. Padmapriya ◽  
M. Nadhiya
Keyword(s):  
Methylene Blue ◽  
Ascorbic Acid ◽  
Modified Electrode ◽  
Electrode Surface ◽  
Graphite Electrode ◽  
Low Cost ◽  
Differential Pulse ◽  
Selective Determination ◽  
The Stability

An electrochemical sensor has been developed using methylene blue (MB) unctionalized graphite for the selective determination of dopamine in the presence of ascorbic acid. The immobilization of methylene blue on graphite was done by carbodiimide coupling method. The methylene blue functionalized graphite was characterized by SEM, FTIR spectroscopy and UV-visible spectroscopy. The immobilization of methylene blue functionalized graphite (MB-G) on the electrode surface was made by drop casting a small volume of MB-G dispersed methanol solution on the electrode surface. About 5 L of 0.5 % Nafion solution was also dropcasted for the stability and selectivity. The MB-G modified electrode was characterized by cyclic voltammetry. The modified electrode promotes the electrocatalytic oxidation of dopamine at a lower potential of 160 mV. The selective determination of dopamine in the presence of 100 times higher concentration of ascorbic acid was achieved by differential pulse voltammetry. The modified electrode offered a simple, selective and sensitive determination of low levels of dopamine. Also the oxidation over potential was reduced to an extent of 360 mV comparing with the bare graphite electrode. The proposed sensor has the advantage of easy fabrication, low cost, good sensitivity, reproducibility and stability.

Quantitative Determination of α-Arbutin, β-Arbutin, Kojic Acid, Nicotinamide, Hydroquinone, Resorcinol, 4-Methoxyphenol, 4-Ethoxyphenol, and Ascorbic Acid from Skin Whitening Products by HPLC-UV

2015 ◽  
Vol 98 (1) ◽  
pp. 5-12 ◽  
Author(s):  
Yan-Hong Wang ◽  
Cristina Avonto ◽  
Bharathi Avula ◽  
Mei Wang ◽  
Diego Rua ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Kojic Acid ◽  
Single Injection ◽  
Solvent System ◽  
Reversed Phase ◽  
Skin Whitening ◽  
Ph Values ◽  
Different Types ◽  
The Stability

Abstract An HPLC-UV method was developed for the quantitative analysis of nine skin whitening agents in a single injection. These compounds are α-arbutin, β-arbutin, kojic acid, nicotinamide, resorcinol, ascorbic acid, hydroquinone, 4-methoxyphenol, and 4-ethoxyphenol. The separation was achieved on a reversed-phase C18 column within 30 min. The mobile phase was composed of water and methanol, both containing 0.1% acetic acid (v/v). The stability of the analytes was evaluated at different pH values between 2.3 and 7.6, and the extraction procedurewas validated for different types of skin whitening product matrixes, which included two creams, a soap bar, and a capsule. The best solvent system for sample preparation was 20 mM NaH2PO4 containing 10% methanol at pH 2.3. The analytica method was validated for accuracy, precision, LOD, and LOQ. The developed HPLC-UV method was applied forthe quantitation of the nine analytes in 59 skin whitening products including creams, lotions, sera, foams, gels, mask sheets, soap bars, tablets, and capsules.

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