Ultraviolet photodegradation of folic acid

Off, Morten Kristian; Steindal, Arnfinn Hykkerud; Porojnicu, Alina Carmen; Juzeniene, Asta; Vorobey, A. V.; Johnsson, Anders; Moan, Johan Emelian

doi:10.1016/j.jphotobiol.2005.03.001

Cited by 211 publications

(149 citation statements)

References 31 publications

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“…Photooxidation of PteGlu under UV-A radiation may be divided into three stages: (i) in the first phase, p-aminobenzoylglutamic acid (PABA-Glu) and 6-formylpterin (Fop) are photogenerated, with a pseudo-zero-order kinetics; (ii) in the second phase, Fop photoinduces the photooxidation of PteGlu and its degradation process is accelerated; (iii) in the third phase, the degradation of Fop to 6-carboxypterin (Cap) is the dominating process (Scheme 5) [53][54][55][56]. Reactive oxygen species, such as H 2 O 2 and O 2˙− , are formed during the photooxidation of PteGlu into Fop, and in the reaction where Fop is converted into Cap (Scheme 5) [56].…”

Section: Photoinactivation Of Tyrosinasementioning

confidence: 99%

Photosensitization of peptides and proteins by pterin derivatives

et al. 2017

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Proteins are one of the preferential targets of the photosensitized damaging effects of ultraviolet (UV) radiation on biological system. Pterins belong to a family of heterocyclic compounds, which are widespread in living systems and participate in relevant biological functions. In pathological conditions, such as vitiligo, oxidized pterins accumulate in the white skin patches of patients suffering this depigmentation disorder. It is known that pterins are able to photosensitize damage in nucleotides and DNA by type I (electron transfer) and type II (singlet oxygen) mechanisms. Recently, it has been demonstrated that proteins and its components may also be damaged when solutions containing both proteins and pterin are exposed to UV-A radiation. Therefore, given the biological and medical relevance of the photosensitizing properties of these molecules, we present in this article an overview of the capability of different pterin derivatives to photoinduce damage in proteins present in the skin, focusing our attention on the chemical modifications of tyrosine and tryptophan residues.

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Section: Photoinactivation Of Tyrosinasementioning

confidence: 99%

Photosensitization of peptides and proteins by pterin derivatives

et al. 2017

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“…However, folic acid and folates are rather unstable molecules. In fact, folic acid is photosensitive and suffers from oxidative degradation, which is enhanced by oxygen, heat and acid pH conditions (Akhtar, Khan, & Ahmad, 1999;Off et al, 2005). This results in a splitting of the molecule into biologically inactive forms (Madziva, Kailasapathy, & Phillips, 2006) and, as suggested from different studies, in a significant decrease in the oral bioavailability of the vitamin (Ohrvik & Witthoft, 2011;O'Leary & Sheehy, 2001).…”

Section: Introductionmentioning

confidence: 99%

Casein nanoparticles as carriers for the oral delivery of folic acid

et al. 2015

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Alimentary proteins can be viewed as an adequate material for the preparation of nanoparticles and microparticles. They offer several advantages such as their digestibility, price and a good capability to interact with a wide variety of compounds and nutrients. The aim of this work was to prepare and characterize casein nanoparticles for the oral delivery of folic acid. These nanoparticles were prepared by a coacervation process, stabilized with either lysine or arginine and, finally, dried by spray-drying. For some batches, the effect of a supplementary treatment of nanoparticles (before drying) with hydrodynamic high pressure on the properties of the resulting carriers was also evaluated. The resulting nanoparticles displayed a mean size close to 150 nm and a folic acid content of around 25 mg per mg nanoparticle. From the in vitro release studies, it was observed that casein nanoparticles acted as gastro-resistant devices and, thus, folic acid was only released under simulated intestinal conditions. For the pharmacokinetic study, folic acid was orally administered to laboratory animals as a single dose of 1 mg/kg. Animals treated with folic acidloaded casein nanoparticles displayed significantly higher serum levels than those observed in animals receiving an aqueous solution of the vitamin. As a consequence the oral bioavailability of folic acid when administered in casein nanoparticles was calculated to be around 52%, a 50% higher than with the traditional aqueous solution. Unfortunately, the treatment of casein nanoparticles by hydrodynamic high pressure modified neither the release profile of the vitamin nor its oral bioavailability.

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“…Some investigators 6,7,19) have already shown that PGA was degraded by UVA exposure, however, these experiments just showed the detection of the degraded compounds. No quantitative experiment had been reported.…”

Section: Discussionmentioning

confidence: 99%