Copper
F. Howard Kratzer, Pran Vohra in Chelates in Nutrition, 2018
Copper (Cu) is absorbed from the duodenum in man and chicks, from the upper jejunum in dogs, from the small intestine and colon in pigs, and from the stomach and small intestine in rats. Cu absorption is inhibited by other ions, probably at the level of the intestine. After absorption, Cu is found in the plasma bound with a protein, ceruloplasmin, in most species other than chicks and turkeys. If one assumes that phytic acid in isolated soybean protein is responsible for the majority of the Cu-binding activity, it is probable that its effect is minimal on Cu availability. Cu is complexed very readily by amino acids, peptides, and certain proteins. The ascorbic acid seemed to intensify the effect of a Cu deficiency, which was not alleviated by the addition of reserpine or estrogen. Ascorbic acid depressed the absorption of 64Cu from a ligated intestinal segment.
Vitamin C (Ascorbic Acid)
Howerde E. Sauberlich in Laboratory Tests for the Assessment of Nutritional Status, 2018
Vitamin C is used as a generic term for all compounds qualitatively exhibiting the biological properties of ascorbic acid. A deficiency of vitamin C leads to scurvy. Scurvy is characterized by hemorrhagic disorders such as petechiae and ecchymoses. Scurvy may be associated with loosening of the teeth, gingivitis, and anemia. In vitamin C deficiency, underhydroxylated collagen is formed. This defective collegen is subject to intracellular degradation. The extensive consumption of vitamin C has been stimulated by claims of various benefits derived from its use. The measurement of the ascorbic acid concentrations in whole blood or red blood cells appeared to provide no advantage over plasma ascorbic acid measurements for evaluating vitamin C status. In comparison with measurements of ascorbic acid in leucocytes, red blood cells, or whole blood, plasma ascorbic acid analysis remains the most feasible procedure for evaluating vitamin C nutritional status in individuals or population groups.
Treatment of skin with antioxidants
Roger L. McMullen in Antioxidants and the Skin, 2018
This chapter discusses some most common antioxidants used in skin care formulations, starting with the most fundamental species: vitamin E, vitamin C, and coenzyme Q (coQ). The use of antioxidants in various skin treatments is a concrete approach to improve the overall health state of skin. For all its benefits, vitamin E has some inherent problems with topical treatment, resulting in contact dermatitis in some individuals. Ascorbic acid, or vitamin C, is the major water-soluble antioxidant in skin and most other body tissues. Vitamin C is a cofactor important for the synthesis of collagen and maintenance of sustainable metalloproteinase (MMP) levels. Coenzyme Q is increasingly found in personal care products where it is typically used as an antiaging or anti-wrinkling active ingredient. Molecular biology studies on fibroblast cell culture systems demonstrated that coQ inhibits the UV-induced upregulation of MMPs, melanin synthesis, and production of inflammatory cytokines.
Effects of Ascorbic Acid and Analogs on the Activity of Testicular Hyaluronidase and Hyaluronan Lyase on Hyaluronan
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2003
Odilia N. Okorukwu, Koen P. Vercruysse
We have evaluated the inhibition of testicular hyaluronidase and hyaluronan lyase by L-ascorbic acid and chemical analogs. We observed that L-ascorbic acid, D-isoascorbic acid and dehydroascorbic acid inhibited both types of enzymes, but showed stronger effects towards hyaluronan lyase. But these compounds were observed to degrade the substrate, hyaluronan, by themselves. Of the other ascorbic acid analogs tested, saccharic acid inhibited hyaluronan lyase, while not affecting the enzymatic activity of testicular hyaluronidase, nor affecting the physic-chemical stability of hyaluronan. This is the first compound, to our knowledge, to be shown to possess such selective inhibition. Therefore, we propose that saccharic acid could serve as a lead compound for the development of potent and selective inhibitors of bacterial hyaluronan lyase or of polysaccharide lyase enzymes in general as we observed this compound to be capable of inhibiting chondroitinase ABC in addition to hyaluronan lyase.
The diffusion of L(+)-ascorbic acid across DPPC vesicle membranes
Published in Journal of Microencapsulation, 1985
Helmut Sapper, Klaus-Dieter Roth, Wolfgang Lohmann
The transmembrane diffusion of L(+)-ascorbic acid has been studied by means of 1H-n.m.r. spectroscopy using small unilamellar DPPC vesicles as a model system. It is shown that the electro-neutral form of L(+)-ascorbic acid diffuses faster across the membranes than the anionic form by about two orders of magnitude. The diffusion is influenced by a molecular interaction between L (+)-ascorbate and the membrane surface and depends also on the fluidity of the membrane. The calculated permeation coefficients of neutral L(+)-ascorbic acid are between 6 × 10-10 and 3 x10-8 cms-1 (35-52°C).
Vitamin C Bioequivalence from Gummy and Caplet Sources in Healthy Adults: A Randomized-Controlled Trial
Published in Journal of the American College of Nutrition, 2020
Malkanthi Evans, Najla Guthrie, H. Kelly Zhang, William Hooper, Andrew Wong, Annahita Ghassemi
Background: The efficacy of Vitamin C (L-ascorbic acid) supplementation can be assessed by uptake into the blood and retention in leukocytes. Vitafusion® Power C gummy is an alternative vitamin C source which may exhibit similar bioavailability to comparator caplets. Objective: The objective of this study was to evaluate the bioequivalence of vitamin C from a vitafusion® Power C gummy formulation and a comparator caplet in healthy adults. Methods: Thirty healthy men and women, 34.0 ± 11.4 years of age and Body Mass Index (BMI) 24.5 ± 3.6 kg/m2 completed the randomized examiner-blind, comparator controlled, cross-over trial with two sequences: gummy (1000 mg) to caplet (1000 mg) or caplet to gummy. Intake of foods fortified with Vitamin C was restricted 7 days prior to each dosing. Blood samples were collected pre-dose and at 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12 and 24 h post-dose for plasma and leukocytes; and urine was collected pre-dose and between 0-2, 2-4, 4-8, 8-12 and 12-24 h post-dose for L-ascorbic acid analysis. Results: Vitafusion® Power C gummy and comparator caplet demonstrated similar plasma absorption profiles as there were no significant differences in plasma L-ascorbic acid total Area Under the Curve (AUC)0-24h, and Tmax between gummy and caplet. The caplet did elicit a significantly higher Cmax than the gummy (p