Identification of 3,4-Dihydroxy-2-oxo-butanal (L-threosone) as an Intermediate Compound in Oxidative Degradation of Dehydro-L-ascorbic Acid and 2,3-Diketo-L-gulonic Acid in a Deuterium Oxide Phosphate Buffer

2001 ◽  
Vol 65 (8) ◽  
pp. 1707-1712 ◽  
Author(s):  
Yoko NISHIKAWA ◽  
Yuka TOYOSHIMA ◽  
Tadao KURATA
Keyword(s):  
Ascorbic Acid ◽  
Phosphate Buffer ◽  
Deuterium Oxide ◽  
Oxidative Degradation ◽  
Intermediate Compound

scholarly journals Change of Ascorbic Acid Level after Grafting of Tomato Seedlings

1999 ◽  
Vol 54 (9-10) ◽  
pp. 830-833 ◽  
Author(s):  
Akira Wadano ◽  
Mitsuharu Azeta ◽  
Shin-ichi Itotani ◽  
Ai Kanda ◽  
Toshio Iwaki ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Water Stress ◽  
Ascorbate Peroxidase ◽  
Phosphate Buffer ◽  
Acid Level ◽  
Active Oxygen ◽  
Ascorbic Acid Level ◽  
Electrochemical Detector ◽  
Tomato Seedlings ◽  
Severe Water Stress

Grafting is an easy way to produce a new seedling, which can tolerate against various stresses. During the acclimation after grafting, however, the seedlings still suffer a severe water stress. It is well known that water stress produces active oxygen to oxidize ascorbic acid. The concentration of ascorbic acid in the leaves was analyzed by HPLC equipped with an electrochemical detector. The column used was SP-120-5-ODS-BP (DAISO, JAPAN) and elution was performed with 0.1 ᴍ phosphate buffer, pH 3.0. After grafting the seedlings were acclimated under a 6-hr light/dark regimen. The content of ascorbic acid increased gradually during 2 days compared with control. The ascorbate peroxidase showed about constant activity, so the increase of ascorbic acid may be due to its requirement to cure the grafting

scholarly journals Buffer Additives and Packaging Differentially Influence the Stability of Dyes Commonly Used in Chromovitrectomy

2016 ◽  
Vol 1 (3) ◽  
pp. 1-10
Author(s):  
Begoña Parrado Aliod ◽  
Wilfried Kugler ◽  
Tim Häring
Keyword(s):  
Polyethylene Glycol ◽  
Chemical Stability ◽  
Deuterium Oxide ◽  
Oxidative Degradation ◽  
Bromophenol Blue ◽  
Physiological Range ◽  
Vis Spectroscopy ◽  
The Stability ◽  
Acid Violet ◽  
Dye Solutions

Purpose: This study was performed to investigate the chemical stability of different dyes used in chromovitrectomy and the influence of various product parameters on it. Methods: Buffered dye solutions were prepared containing 1.5 g/L acid violet 17, 0.25 g/L brilliant blue G, 1.3 g/L bromophenol blue, and 1.5 g/L trypan blue, combined with deuterium oxide, polyethylene glycol 3350, and D-mannitol as additives. For accelerated storage testing, samples were incubated for 400 h at 80°C corresponding to 2 years according to the Van ‘t Hoff equation. After different incubation times samples were taken for UV/Vis spectroscopy, pH measurement, and osmometry. Results: Depending on dye, additive, and packaging, different solutions exhibit differences in chemical stability and hence shelf life. Packaging in syringes instead of vials increases dye stability. Additives may negatively influence important parameters, e.g. polyethylene glycol 3350 increases osmolality beyond the physiological range. Notably, acid violet 17 is chemically unstable except in D-mannitol-containing buffer, packed in syringes. However, simultaneously, D-mannitol leads to a pH shift below 7.0. Conclusion: In summary, dye solutions filled in syringes should be preferred to vials to slow down oxidative degradation. Especially acid violet 17 solutions should be used with caution because the addition of D-mannitol may contribute to pH values beyond the physiological range.

Fabrication of Ascorbic Acid Biosensor Based on Coupling Polyethylene Glycol Modified Silk Fibroin Membrane onto Glassy Carbon Electrode

2016 ◽  
Vol 835 ◽  
pp. 63-70
Author(s):  
Pacharawan Ratanasongtham ◽  
Lalida Shank ◽  
Jaroon Jakmunee ◽  
Ruangsri Watanesk ◽  
Surasak Watanesk
Keyword(s):  
Ascorbic Acid ◽  
Polyethylene Glycol ◽  
Glassy Carbon Electrode ◽  
Silk Fibroin ◽  
Glassy Carbon ◽  
Phosphate Buffer ◽  
Storage Time ◽  
Initial Response ◽  
Ascorbate Oxidase ◽  
Carbon Electrode

Nowadays biosensors have been extensively used in a wide variety of applications especially in clinical works and food industry. In this work, a specific ascorbic acid (AA) biosensor was developed by immobilizing ascorbate oxidase (ASOD) on a polyethylene glycol (PEG) modified silk fibroin (SF) membrane then coupling to the glassy carbon electrode (GCE). The SF-PEG-ASOD membrane provided the highest enzyme activity in phosphate buffer at pH 5. As being the electrode, the SF-PEG-ASOD modified GCE displayed the highest response when it is operated under the condition of 0.40 mg/L of ASOD in phosphate buffer at pH 5. This biosensor provided both good linearity (r2 = 0.999 in the range of 1.0-10.0 mM) and sensitivity with short response time (26s). It also exhibited good anti-interference ability with the storage time of 5 days without changing its initial response.

scholarly journals Ekstraksi dan Bioaktivitas Antioksidan Pigmen Fikoeritrin dari Rumput Laut Merah Halymenia sp.

2020 ◽  
Vol 15 (2) ◽  
pp. 115
Author(s):  
Tias Suci Lailani ◽  
Ifah Munifah ◽  
Hermanto Hermanto
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Phosphate Buffer ◽  
Extraction Time ◽  
Red Seaweed ◽  
Antioxidant Power ◽  
Extract Yield ◽  
Ferric Reducing Antioxidant Power

Fikoeritrin adalah pigmen dari rumput laut merah Halymenia sp. dengan aktivitas antioksidan yang potensial untuk dikembangkan dalam bidang nutraseutikal. Ekstraksi fikoeritrin dapat dilakuan dengan berbagai jenis pelarut. Namun, penggunaan pelarut yang tidak sesuai dapat berdampak terhadap rendemen, kemurnian, dan juga bioaktivitas ekstrak fikoeritrin. Oleh karena itu, penelitian ini bertujuan untuk mendapatkan jenis pelarut dan durasi waktu ekstraksi (secara maserasi) yang tepat sehingga menghasilkan ekstrak dengan rendemen, kemurnian, dan daya antioksidan fikoeritrin terbaik. Ekstraksi dilakukan menggunakan tiga jenis pelarut (akuabides; buffer fosfat pH 6,8; dan aseton 80%) dengan variasi waktu maserasi (24, 48, 72, dan 96 jam). Spektrofotometri Ultraviolet-Visibel (UV-Vis) dipergunakan dalam identifikasi fikoeritrin, sementara Ferric Reducing Antioxidant Power (FRAP) merupakan metode dalam telaah daya antioksidan ekstrak. Hasil penelitian menunjukkan bahwa terdapat perbedaan jumlah rendemen ekstrak (w/w segar) dari ketiga pelarut, yaitu 1,76% (akuabides); 0,91% (aseton 80%); dan 2,91% (buffer fosfat pH 6,8). Selain itu, waktu ekstraksi juga menyebabkan perbedaan jumlah rendemen, yaitu 1,72% (24 jam); 1,51% mg/mL (48 jam); 1,37% (72 jam); dan 1,43% (96 jam). Hasil ini menunjukkan bahwa pelarut buffer fosfat dengan durasi waktu maserasi 24 jam adalah metode yang terbaik untuk mendapatkan rendemen fikoeritrin tertinggi dari rumput laut merah Halymenia sp. Aktivitas antioksidan dari ekstrak buffer fosfat ini terdeteksi sebesar 3,14 mg ekuivalen asam askorbat/100 g ekstrak pada konsentrasi 10 mg/mL. ABSTRACTPhycoerythrin is a pigment from red seaweed Halymenia sp., with antioxidant activity which is prospective in nutraceutical development. There are several solvents that could be used in the extraction of phycoerythrin. However, the use of inappropriate solvents may impact the yield, purity, and bioactivity of phycoerythrin extract. Therefore, this study aimed to obtain the type of solvent and the duration of extraction (with maceration technique) to produce the highest yield, purity, and antioxidant activity of phycoerythrin extract. Extraction was carried out using three types of solvents (aquabidest, phosphate buffer pH 6.8, and acetone 80%) with variations in extraction time (24, 48, 72, and 96 hours). Spectrophotometric Ultraviolet-Visible (UV-Vis) was used to identify the phycoerythrin, and Ferric Reducing Antioxidant Power (FRAP) was applied to analyze the antioxidant activity in the extract. The results showed that there were differences in the amount of extract yield (w/w fresh) from three solvents, which was 1.77% (aquabidest), 0.91% (acetone 80%), and 2.91% (phosphate buffer pH 6.8). Moreover, extraction duration was also affecting the amount of yield, which was1.78% (24 hours), 1.51% mg/mL (48 hours), 1.37% (72 hours), and 1.43% (96 hours). These results indicated that the phosphate buffer solvent with a 24-hour extraction duration was the best method to get the highest yield of phycoerythrin from the red seaweed Halymenia sp. The antioxidant activity from the phosphate buffer extract was detected up to 3.14 mg equivalent ascorbic acid /100 g extract at a concentration of 10 mg/mL.

scholarly journals Amperometric biosensor for ascorbic acid

2005 ◽  
Vol 30 (2) ◽  
pp. 37-43 ◽  
Author(s):  
I. N. Tomita ◽  
A. Manzoli ◽  
F. L. Fertonani ◽  
H. Yamanaka
Keyword(s):  
Ascorbic Acid ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Phosphate Buffer ◽  
High Performance ◽  
Covalent Bond ◽  
Oxygen Depletion ◽  
Ascorbate Oxidase ◽  
Carrier Solution ◽  
Pharmaceutical Samples

A L-ascorbic acid biosensor based on ascorbate oxidase has been developed. The enzyme was extracted from the mesocarp of cucumber (Cucumis sativus) by using 0.05 mol L-1 phosphate buffer, pH 5.8 containing 0.5 mol L-1 NaCl. After the dialysis versus phosphate buffer 0.05 mol L-1 pH 5.8, the enzyme was immobilized onto nylon net through glutaraldehyde covalent bond. The membrane was coupled to an O2 electrode and the yielding reaction monitored by oxygen depletion at -600 mV using flow injection analysis optimized to 0.1 mol L-1 phosphate buffer pH 5.8, as the carrier solution and flow-rate of 0.5 mL min-1. The ascorbic acid calibration curve was linear from 1.2x10-4 to 1.0x10-3 mol L-1. The evaluation of biosensor lifetime leads to 500 injections. Commercial pharmaceutical samples were analyzed with the proposed method and the results were compared with those obtained by high-performance liquid chromatography (HPLC).

SOME STUDIES OF WOUND HEALING: EXPERIMENTAL METHODS, EFFECT OF ASCORBIC ACID AND EFFECT OF DEUTERIUM OXIDE

1964 ◽  
Vol 4 (5) ◽  
pp. 543-566 ◽  
Author(s):  
S M Levenson ◽  
L V Crowley ◽  
E F Geever ◽  
H Rosen ◽  
C W Berard
Keyword(s):  
Wound Healing ◽  
Ascorbic Acid ◽  
Deuterium Oxide ◽  
Experimental Methods

scholarly journals The inhibition of lipid autoxidation by human caeruloplasmin

1977 ◽  
Vol 168 (2) ◽  
pp. 283-288 ◽  
Author(s):  
D J Al-Timimi ◽  
T L Dormandy
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
Linolenic Acid ◽  
Phosphate Buffer ◽  
Brain Homogenate ◽  
Optimum Conditions ◽  
Lipid Autoxidation

1. Purified caeruloplasmin was shown to inhibit lipid autoxidation induced by ascorbic acid or inorganic iron in the following systems: (a) an emulsion of linolenic acid in water; (b) an untreated ox brain homogenate in phosphate buffer; (c) a similar homogenate whose susceptibility to autoxidation had been abolished by dialysis or by heating and then restored by the above pro-oxidants. 2. The optimum conditions for this antioxidant activity were studied. 3. Caeruloplasmin did not inhibit autoxidation by u.v. irradiation in dialysed or preheated homogenates. 4. The apoprotein (without copper) had no antioxidant activity, whereas CuSO4 alone was much less effective as an antioxidant. 5. Iron-free transferrin also had some antioxidant activity.

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