Fatty acid monoesters of 1-ascorbic acid and d-isoascorbic acid

1943 ◽  
Vol 20 (11) ◽  
pp. 224-226 ◽  
Author(s):  
Daniel Swern ◽  
A. J. Stirton ◽  
J. Turer ◽  
P. A. Wells
Keyword(s):  
Ascorbic Acid ◽  
Fatty Acid ◽  
Isoascorbic Acid

Requirement for Na(+)-dependent ascorbic acid transport in osteoblast function

1995 ◽  
Vol 268 (6) ◽  
pp. C1430-C1439 ◽  
Author(s):  
R. T. Franceschi ◽  
J. X. Wilson ◽  
S. J. Dixon
Keyword(s):  
Ascorbic Acid ◽  
Vitamin C ◽  
Disulfonic Acid ◽  
Acid Transport ◽  
Transport Activity ◽  
Intracellular Accumulation ◽  
Extracellular Medium ◽  
Isoascorbic Acid ◽  
Transport Inhibitors ◽  
Ascorbic Acid Transport

Ascorbic acid is necessary for expression of the osteoblast phenotype. We examined whether Na(+)-dependent transport is required for MC3T3-E1 preosteoblast cells to respond to vitamin C and investigated the role of membrane transport in the intracellular accumulation and function of ascorbate. MC3T3-E1 cells were found to possess a saturable, stereoselective, Na(+)-dependent ascorbic acid transport activity that is sensitive to the transport inhibitors sulfinpyrazone, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, and phloretin. Transport activity showed no competition with glucose or 2-deoxyglucose and was not inhibited by cytochalasin B, indicating that it is distinct from known hexose transporters. On addition of 100 microM ascorbic acid to the extracellular medium, intracellular concentrations of 10 mM were reached within 5-10 h and remained constant for up to 24 h. A good correlation was observed between intracellular ascorbic acid concentration and rate of hydroxyproline synthesis. Although ascorbic acid was transported preferentially compared with D-isoascorbic acid, both isomers had equivalent activity in stimulating hydroxyproline formation once they entered cells. Marked stereoselectivity for extracellular L-ascorbic acid relative to D-isoascorbic acid was also seen when alkaline phosphatase and total hydroxyproline were measured after 6 days in culture. Moreover, ascorbic acid transport inhibitors that prevented intracellular accumulation of vitamin blocked the synthesis of hydroxyproline. Thus Na(+)-dependent ascorbic acid transport is required for MC3T3-E1 cells to achieve the millimolar intracellular vitamin C concentrations necessary for maximal prolyl hydroxylase activity and expression of the osteoblast phenotype.

Weak measurement-based sensor for the rapid identification of L(+)-ascorbic acid and D(-)-isoascorbic acid

2019 ◽  
Vol 58 (31) ◽  
pp. 8583
Author(s):  
Suyi Zhong ◽  
Tian Guan ◽  
Yang Xu ◽  
Chongqi Zhou ◽  
Lixuan Shi ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Rapid Identification ◽  
Weak Measurement ◽  
Isoascorbic Acid

Determination of ascorbic acid, dehydroascorbic acid, and isoascorbic acid in blood

1986 ◽  
Vol 325 (5) ◽  
pp. 473-475 ◽  
Author(s):  
Jörg Schreiber ◽  
Wolfgang Lohmann ◽  
Dietrich Unverzagt ◽  
Albert Otten
Keyword(s):  
Ascorbic Acid ◽  
Dehydroascorbic Acid ◽  
Isoascorbic Acid

Effect of forage conservation method, concentrate level and propylene glycol on the fatty acid composition and vitamin content of cows' milk

2005 ◽  
Vol 72 (3) ◽  
pp. 349-361 ◽  
Author(s):  
Kevin J Shingfield ◽  
Pirjo Salo-Väänänen ◽  
Eero Pahkala ◽  
Vesa Toivonen ◽  
Seija Jaakkola ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Ascorbic Acid ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Milk Fat ◽  
Milk Fatty Acid ◽  
Vitamin Content ◽  
Concentrate Level ◽  
Conservation Method

Based on potential health benefits, there is a need to develop effective strategies for enhancing milk fat concentrations of cis-9 18[ratio ]1, 18[ratio ]3 n-3 and conjugated linoleic (CLA) content in milk without compromising the sensory or storage characteristics of processed milk or dairy products. Sixteen Finnish Ayrshire dairy cows were used in a cyclic change-over experiment with four 21-d experimental periods and a 4×2×2 factorial arrangement of treatments to evaluate the effects of forage conservation method, concentrate level and supplements of propylene glycol (PG), and their interactions on milk fatty acid composition and vitamin content. Experimental treatments consisted of four conserved forages offered ad libitum, supplemented with two levels of a standard concentrate (7 or 10 kg/d) and PG (0 and 210 g/d) fed as three equal meals. Primary growths of timothy and meadow fescue sward were conserved by ensiling with none (NA), an inoculant enzyme preparation (IE) or a formic acid based (FORM) additive or as hay 1 week later. Conservation of grass by drying rather than ensiling resulted in lower forage 18[ratio ]2n-6, 18[ratio ]3n-3, total fatty acid and fat-soluble vitamin concentrations. In spite of lower intakes, milk fat 18[ratio ]2n-6 and 18[ratio ]3n-3 content was higher (P<0·05) for hay than for silage diets (12·1, 9·6, 9·6 and 9·3 and 5·00, 3·51, 4·27 and 2·93 g/kg total fatty acids, for hay, NA, IE and FORM silages, respectively). Forage conservation method had no clear effects on milk trans 18[ratio ]1 or CLA content. Compared with silage, hay diets resulted in milk containing lower (P<0·001) riboflavin, α-tocopherol and β-carotene concentrations, but had no effect on ascorbic acid, thiamine, pyridoxine or retinol content. Feeding more concentrates had no effect on milk fatty acid composition or milk vitamin content, other than lowering (P<0·001) 16[ratio ]0 concentrations from 348 to 338 g/kg fatty acids. Supplements of PG led to small (P<0·05) increases in milk 13[ratio ]0 anteiso and 15[ratio ]0 content from 1·06 and 11·3 to 1·22 and 12·6 g/kg fatty acids and reduced (P<0·05) the concentrations of ascorbic acid (16·1 v. 15·1 g/kg milk).

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