Chemical Determination of Ascorbic, Dehydroascorbic, and Diketogulonic Acids

Roe, Joseph H.

doi:10.1002/9780470110171.ch5

Cited by 218 publications

(50 citation statements)

References 24 publications

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“…Ascorbic acid was estimated according to the method of Roe (1964) which is based on the reduction of 2, 6-dichlorophenol indophenol by ascorbic acid. Method of Smith (1985) was employed for determining the level of oxidized, reduced and total glutathione.…”

Section: Methodsmentioning

confidence: 99%

Oxidative stress and antioxidant systems in Guava (Psidium guajava L.) fruits during ripening

Mondal

Malhotra

Jain

et al. 2009

Physiol Mol Biol Plants

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Two varieties of guava viz., L-49 and Hisar Safeda differing in their shelf lives were analyzed for various components of oxidative stress and of enzymatic and non-enzymatic antioxidative system at different stages of fruit ripening. Indices of oxidative stress viz., lipoxygenase activity, malondialdehyde value and H 2 O 2 content increased throughout during ripening in both the varieties. The extent of oxidative stress was more pronounced in Hisar Safeda (shelf life 3-4 days) than in L-49 (shelf life 7-8 days). Except for superoxide dismutase, activities of all other antioxidative enzymes viz., catalase, peroxidase, ascorbate peroxidase and glutathione reductase increased up to color turning stage and decreased thereafter. Superoxide dismutase activity, however, increased upto ripe stage followed by a decline. Contents of ascorbic acid and glutathione (total, oxidized and reduced) were found to be the maximum at turning and mature stage, respectively. It is inferred that ripening of guava fruit is accompanied by a progressive increase in oxidative/ peroxidative stress which induces antioxidant system but not until later stages of ripening. Over-accumulation of ROS due to dysfunctioning of ROS scavenging system at later stages of fruit ripening appears to be responsible for loss of tissue structure as observed in ripened and over-ripened fruits.

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Section: Methodsmentioning

confidence: 99%

Oxidative stress and antioxidant systems in Guava (Psidium guajava L.) fruits during ripening

Mondal

Malhotra

Jain

et al. 2009

Physiol Mol Biol Plants

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“…23 The reaction mixture included distilled water, trichloroacetic acid (TCA) and DNPH. The samples were incubated at 37°C and, then, the reaction was interrupted for the addition of 65% sulfuric acid (H 2 SO 4 ).…”

Section: Analytical Determinationsmentioning

confidence: 99%

Obesity, bariatric surgery and oxidative stress

Horn

Gelatti

Mori

et al. 2017

Rev. Assoc. Med. Bras.

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Introduction: Obesity refers to the accumulation of fatty tissues and it favors the occurrence of oxidative stress. Alternatives that can contribute to body weight reduction have been investigated in order to reduce the production of reactive oxygen species responsible for tissue damage. The aim of the current study was to assess whether the oxidant and antioxidant markers of obese women before and after bariatric surgery were able to reduce oxidative damage. Method:We have assessed 16 morbidly obese women five days before and 180 days after the surgery. The control group comprised 16 non-obese women. Levels of thiobarbituric acid-reactive substances, carbonylated proteins, reduced glutathione and ascorbic acid were assessed in the patients' plasma. Results: Levels of lipid peroxidation and protein carbonylation in the pre-surgical obese women were higher than those of the controls and post-surgical obese women. Levels of reduced glutathione in the pre-surgical obese women were high compared to the controls, and declined after surgery. Levels of ascorbic acid fell in the pre--surgical obese women compared to the control and post-surgical obese women. Conclusion: Body weight influences the production of reactive oxygen species. Bariatric surgery, combined with weight loss and vitamin supplementation, reduces cellular oxidation, thus reducing tissue damage.

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“…These products form the derivative bis-2, 4-dinitrophenylhydrazine when treated with 2, 4-dinitrophenylhydrazine. This compound undergoes a rearrange ment to form a product which can be measured at 520 nm [11].…”

Section: Estimation Of Serum Analytesmentioning

confidence: 99%