Degradation Kinetics of Chlorogenic Acid at Various pH Values and Effects of Ascorbic Acid and Epigallocatechin Gallate on Its Stability under Alkaline Conditions

2013 ◽  
Vol 61 (4) ◽  
pp. 966-972 ◽  
Author(s):  
Yusaku Narita ◽  
Kuniyo Inouye
Keyword(s):  
Ascorbic Acid ◽  
Chlorogenic Acid ◽  
Degradation Kinetics ◽  
Epigallocatechin Gallate ◽  
Ph Values ◽  
Alkaline Conditions ◽  
Kinetics Of

scholarly journals Relevance and Standardization of In Vitro Antioxidant Assays: ABTS, DPPH, and Folin–Ciocalteu

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Helena Abramovič ◽  
Blaž Grobin ◽  
Nataša Poklar Ulrih ◽  
Blaž Cigić
Keyword(s):  
Ascorbic Acid ◽  
Chlorogenic Acid ◽  
Gallic Acid ◽  
Caffeic Acid ◽  
Sulfonic Acid ◽  
Epigallocatechin Gallate ◽  
The Other ◽  
Oh Groups ◽  
Standard Compound

Trolox, gallic acid, chlorogenic acid, caffeic acid, catechin, epigallocatechin gallate, and ascorbic acid are antioxidants used as standards for reaction with chromogenic radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH⋅) and 2,2′-azino-bis-3-ethylbenzotiazolin-6-sulfonic acid (ABTS⋅+), and Folin–Ciocalteu (FC) reagent. The number of exchanged electrons has been analyzed as function of method and solvent. A majority of compounds exchange more electrons in FC assay than in ABTS and DPPH assays. In reaction with chromogenic radicals, the largest number of electrons was exchanged in buffer (pH 7.4) and the lowest reactivity was in methanol (DPPH) and water (ABTS). At physiological pH, the number of exchanged electrons of polyphenols exceeded the number of OH groups, pointing to the important contribution of partially oxidized antioxidants, formed in the course of reaction, to the antioxidant potential. For Trolox, small impact on the number of exchanged electrons was observed, confirming that it is more suitable as a standard compound than the other antioxidants.

scholarly journals Degradation Kinetics of Catechin in Aqueous Solution in the Presence of Ascorbic Acid or Octanoyl Ascorbate

2009 ◽  
Vol 10 (2) ◽  
pp. 117-124 ◽  
Author(s):  
Yoshiyuki WATANABE ◽  
Tatsunori OKAYASU ◽  
Kana IDENOUE ◽  
Shuji ADACHI
Keyword(s):  
Aqueous Solution ◽  
Ascorbic Acid ◽  
Degradation Kinetics ◽  
Kinetics Of
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