Previous studies showed that the intact carbon chain of glucose can serve as a precursor for the synthesis of ascorbic acid in the rat (l-3). Evidence for such a precursor relationship came from experiments in which glucose tracers labeled in carbon 1 and carbon 6 were administered to rats, and the L-ascorbic acid isolated from urine was labeled predominantly in carbon 6 and carbon 1, respectiv...

     Osteoporosis is a silent epidemy of today's world, and is also a prevalent problem of health in Iran. The role of nutrients such as ascorbic acid, a key antioxidant vitamin, in this disease has recently attracted researchers' attention. In this study, we studied the relation between plasma ascorbic acid concentration and bone mineral density (BMD) in women referring to Jami clinic, Tehran,...

In order to study the potential benefit of ascorbic acid in asthma we investigated its role in exercise-induced bronchospasm (EIB). Twelve asthmatic subjects were recruited on the basis of findings compatible with EIB. On two subsequent days the subjects ingested 500 mg. of ascorbic acid or a placebo. The study was performed in a double-blind randomized fashion. Partial and maximal expiratory f...

1. Pregnant guinea-pigs receiving a low dose of L-ascorbic acid (0.2 mg/100 g body-weight per d) developed a hypercholesterolaemia in the third trimester of pregnancy, whereas no change in serum cholesterol levels was observed in pregnant animals receiving a higher dose of the vitamin (2 mg/100 g body-weight per d). 2. Pregnancy in the group of guinea-pigs receiving the higher dose of L-ascorbi...

BACKGROUND: Diabetes mellitus is a chronic metabolic disorder characterized by hyperglycaemia. Increased oxidative stress and decreased antioxidant levels are the leading cause of diabetes and diabetic complications. So it is felt that supplementation of antioxidants may be useful in controlling the glucose levels and to postpone the occurrence of diabetic complications. The objective of our st...

We present a method for measuring ascorbic acid in methanol/trichloroacetic acid extracts prepared from human plasma after enzymatic oxidation of ascorbic acid to dehydroascorbic acid by ascorbate oxidase. Samples were assayed by spectrophotometrically monitoring the kinetics of the concentration-dependent absorbance changes of dehydroascorbic acid with phosphate-citrate-methanol buffers. Ascor...

The sulphur aroma compounds produced from a phosphate-buffered solution (pH 8) of l-cysteine and l-, l-[1-13C] or l-[4-13C] ascorbic acid, heated at 140±2°C for 2h, were examined by headspace SPME in combination with GC-MS. MS data indicated that C-1 of l-ascorbic acid was not involved in the formation of sulphur aroma compounds. The sulphur aroma compounds formed by reaction of l-ascorbic acid...

Abstract In this study ameliorative effects of ascorbic acid (0.5 mM) on onion (Allium cepa L. cv. Red Azarshahr) under copper stress (Cu: 6.5 μM) were studied. Fresh weights of leaves and roots were reduced in seven week old plants under excess copper condition. Cu stress also reduced membrane stability index in leaves. There was a considerable increase in H2O2 content and lipid peroxidation i...

Introduction: Lead toxicity induces retinal cell apoptosis. Vitamin C and garlic may decrease lead-induced apoptosis. This study was undertaken to investigate vitamin C and garlic protective effects on lead-induced apoptosis in eye retina. Methods: Pregnant Wistar rats (n = 72) were divided randomly into 9 groups: (L) treated rats with lead acetate in drinking water and (L+AA) with leaded water...

hypophosphite for the conversion of D-glucuronolactone into L-ascorbic acid. 9. The presence of borate or Antabuse, each at mm-concentration, inhibits the conversion of Dglucuronolactone into L-ascorbic acid to about 50 %. 10. The optimum conditions for the action of the enzyme system have been studied. 11. The biosynthesized ascorbic acid has been identified by paper chromatography and by a bi...