abstract this experiment was carried out to determine the effects of proline and ascorbic acid on chilling injury, electrolyte leakage, lipid peroxidation, peroxide hydrogen and antioxidant enzymes activity of thompson grape (vitis vinifera l.) fruit. grape fruits were treated by 0 (control), 250 and 500 µm proline and 0 (control), 2 and 4% ascorbic acid and their combinations, then stored at 1...

Dehydro-L-ascorbic acid, the oxidation product of L-ascorbic acid, is unstable in aqueous solution and decomposed by a hydrolytic disruption of its ring structure to 2,3-diketo-L-gulonic acid. It is shown by means of UV, 'H-, and 13C-NMR spectroscopy that after decarboxylation 3,4,5-trihydroxy-2-keto-L-valeraldehyde, an a-ketoaldehyde, is formed. This substance is oxidized further to L-erythroa...

It is known that, of all animal species studied, only man, other Primates, and the guinea pig are unable to synthesize ascorbic acid. Results obtained in rats, with radioactive glucose, indicate that ascorbic acid is synthesized by a fairly direct route from glucose (l-3), but no information has been available concerning the rate of synthesis and metabolism of ascorbic acid. Such information wo...

Ochromonas danica Pringsheim, a freshwater chrysomonad, converts d-glucose into l-ascorbic acid over a metabolic pathway that ;inverts' the carbon chain of the sugar. In this respect, l-ascorbic acid formation resembles that found in ascorbic acid-synthesizing animals. It differs from this process in that d-galacturonate and l-galactono-1,4-lactone, rather than d-glucuronate and l-gulono-1,4-la...

The inhibiting effect of ascorbic acid, citric acid and sodium chloride on Polyphenoloxidase (PPO) of Golden Delicious apple cubes was studied. Dipping in ascorbic acid (0.2-10 g/L range) and in NaCl (0.2-1 g/L range) solutions for 5 min increases the PPO activiry. Citric acid solutions (0.2-10 g / L range) have little or no inhibition of PPO. A 90-100% PPO inhibition was obtained with a 5 min ...

Ascorbic acid is concentrated in various ocular compartments where it is thought to protect diurnal animal species against damaging effects of ultraviolet radiation. The authors evaluated the possibility that corneal endothelial cells have specific transport and/or metabolic properties that deliver ascorbic acid to the stroma. Bovine corneal endothelial cells were grown to confluence in multipl...

Metabolic conversion of l-galactono-1, 4-lactone and l-ascorbic acid to (+)-tartaric acid and oxalic acid has been studied in Pelargonium crispum, cv. Prince Rupert. Experiments with specifically labeled substrates suggest a path of conversion involving cleavage of l-ascorbic acid, or a metabolic product of l-ascorbic acid, between C(2) and C(3), such that oxalic acid arises from the two carbon...

Ascorbic acid and nitric oxide are known to play important roles in epilepsy. The aim of present study was to identify the involvement of nitric oxide (NO) in the anticonvulsant effects of ascorbic acid on penicillin-induced epileptiform activity in rats. Intracortical injection of penicillin (500, International Units (IU)) into the left sensorimotor cortex induced epileptiform activity within ...