Dehydro-L-ascorbic acid is usually found in plant tissues in low concentrations and is always associated with ascorbic acid in much higher concentrations. One of the most reliable and direct methods for its estimation is that originally proposed by Roe & Kuether (1943) which is based on the formation of a 2:4-dinitrophenylosazone. Many plant tissues, however, contain so little dehydro-L-ascorbi...

Previous studies have shown that the intact carbon chain of glucose is utilized for the synthesis of L-ascorbic acid in the rat (l-3). Evidence for this precursor relationship came from experiments in which the administration of carbon land carbon 6-labeled glucose tracers resulted in the urinary excretion of n-ascorbic acid labeled predominantly in carbon 6 and carbon 1, respectively. Although...

Detached bean (Phaseolus vulgaris) and strawberry (Fragaria) fruits fed l-gulono-1,4-lactone or l-galactono-1,4-lactone convert this compound, in part, to l-ascorbic acid. When l-galactono-1,4-lactone is given as a 0.25% solution to detached bean shoots, the ascorbic acid content is tripled in less than 10 hours. l-Gulono-1,4-lactone is only 5 to 10% as effective as its epimer. Experiments with...

Dietary administration of 5% L-ascorbic acid plus 3% K2CO3 to male F344 rats clearly enhanced the development of preneoplastic and neoplastic lesions of the urinary bladder initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine. Promotion of carcinogenesis by L-ascorbic acid and K2CO3 was associated with changes in urinary parameters: elevation of pH, increased K+ concentration, and increase in t...

Vitamin C (L-ascorbic acid) is an essential micronutrient that serves as an antioxidant and as a cofactor in many enzymatic reactions. Intestinal absorption and renal reabsorption of the vitamin is mediated by the epithelial apical L-ascorbic acid cotransporter SVCT1 (SLC23A1). We explored the molecular mechanisms of SVCT1-mediated L-ascorbic acid transport using radiotracer and voltage-clamp t...

Skin-lightening agents such as kojic acid, arbutin, ellagic acid, lucinol and 5,5′-dipropylbiphenyl-2,2′-diol are used in ‘anti-ageing’ cosmetics. Cases of allergic contact dermatitis caused by these skin-lightening agents have been reported (1, 2). Vitamin C and its derivatives have also been used in cosmetics as skin-lightening agents for a long time. Vitamin C in topical agents is poorly abs...

Previous studies have shown that L-ascorbic acid is extensively oxidized to respiratory CO? in rats (1, 2) and guinea pigs (3, 4). However, little information is available on the intermediates involved in the metabolism of the vitamin. In the present study experiments carried out with carboxyland uniformly labeled L-ascorbic acid point to the presence in rat kidney of an active enzyme system fo...

OBJECTIVE(S) The aim of this study was to investigate ascorbic acid and garlic protective effects on lead-induced neurotoxicity during rat hippocampus development. MATERIALS AND METHODS 90 pregnant wistar rats were divided randomly into nine groups: 1- Animals received leaded water (L). 2- Rats received leaded water and ascorbic acid (L+AA). 3- Animals received leaded water and garlic juice (...

Ascorbic acid enhances NO bioactivity in patients with vascular disease through unclear mechanism(s). We investigated the role of intracellular ascorbic acid in endothelium-derived NO bioactivity. Incubation of porcine aortic endothelial cells (PAECs) with ascorbic acid produced time- and dose-dependent intracellular ascorbic acid accumulation that enhanced NO bioactivity by 70% measured as A23...