(−)-Riboflavin (vitamin B2) and flavin mononucleotide as visible light photo initiators in the thiol–ene polymerisation of PEG-based hydrogels

2017 ◽  
Vol 8 (6) ◽  
pp. 980-984 ◽  
Author(s):  
R. R. Batchelor ◽  
G. Kwandou ◽  
P. T. Spicer ◽  
M. H. Stenzel
Keyword(s):  
Visible Light ◽  
Flavin Mononucleotide ◽  
Vitamin B2

The photoinitiators used in light mediated hydrogelation have been limited due to cytotoxicity and solubility issues.

Mutual effects between aromatic amino acids and guanosine upon vitamin B2 photosensitization in the presence of visible light

2013 ◽  
Vol 91 (8) ◽  
pp. 684-690
Author(s):  
M. Paulina Montaña ◽  
Gabriela Ferrari ◽  
Eduardo Gatica ◽  
José Natera ◽  
Walter Massad ◽  
...  
Keyword(s):  
Amino Acids ◽  
Visible Light ◽  
Superoxide Radical ◽  
Marked Decrease ◽  
Aromatic Amino Acids ◽  
Quantum Yields ◽  
Vitamin B2 ◽  
Singlet Molecular Oxygen ◽  
Superoxide Radical Anion ◽  
The Individual

Considering the importance of the visible-light-induced photodynamic effect in complex bioenvironments, mutual effects between the individual aromatic amino acids (AAs) tyrosine (Tyr), tryptophan (Trp), and histidine (His) and the nucleoside guanosine (GUO) were investigated in pH 7 aqueous solution with vitamin B2 (riboflavin (Rf)) as a dye sensitizer. The quantum yields of oxygen uptake (Φ–O2) for most of the AA−GUO mixtures studied, taken as a measure of overall photooxidation susceptibility, are not straightforwardly predictable from the individual behaviour of the components of the mixture. The final result depends on several connected factors, such as the respective abilities of the substrates as quenchers of the long-lived Rf triplet excited state and the generated reactive oxygen species singlet molecular oxygen (O2(1Δg)) and superoxide radical anion ([Formula: see text]). A mechanistic interpretation of the Rf-sensitized results can be roughly resumed as follows: Tyr at pH 7 exerts a protective effect on the photooxidation of the mixture Tyr−GUO due to the O2(1Δg) physical quenching by the AA. The same effect was observed for Trp−GUO and His−GUO at pH 7. In these cases, it is attributed to the quenching of 3Rf* by GUO in detriment of the Type II route. For the system Tyr−GUO at pH 9, a marked decrease in the Φ–O2 occurred for the mixture as compared with the respective Φ–O2 for the individual components. It was ascribed to the participation of a radical-mediated mechanism without oxygen consumption in a competitive pathway with the [Formula: see text]-mediated route.

Protective Effect of Boldo and Tea Infusions on the Visible Light-mediated Pro-oxidant Effects of Vitamin B2, Riboflavin¶

2002 ◽  
Vol 75 (6) ◽  
pp. 585-590
Author(s):  
E. Silva ◽  
M. Jopia ◽  
A. M. Edwards ◽  
E. Lemp ◽  
J. R. Fuente ◽  
...  
Keyword(s):  
Visible Light ◽  
Protective Effect ◽  
Vitamin B2 ◽  
Tea Infusions

scholarly journals Plasma riboflavin concentration as novel indicator for vitamin-B2 status assessment: suggested cutoffs and its association with vitamin-B6 status in women

2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Amy Tan ◽  
Mohammad Zubair ◽  
Chia-ling Ho ◽  
Liadhan McAnena ◽  
Helene McNulty ◽  
...  
Keyword(s):  
Older Adult ◽  
Change Point ◽  
Vitamin B6 ◽  
Reference Interval ◽  
Dietary Vitamin ◽  
Flavin Mononucleotide ◽  
Adult Women ◽  
Vitamin B2 ◽  
Riboflavin Deficiency ◽  
Riboflavin Status

AbstractRiboflavin (vitamin B2), as the coenzymes flavin mononucleotide (FMN) and flavin dinucleotide (FAD), is essential for oxidation-reduction reactions and energy metabolism. Riboflavin also interacts with vitamin B12, B6 and folate in one-carbon metabolism, and is required for the conversion of dietary vitamin B6 forms to the coenzyme pyridoxal 5’-phosphate (PLP). Biochemical riboflavin status is rarely measured given the lack of convenient and accessible biomarkers. The current gold-standard marker is erythrocyte glutathione reductase activation coefficient (EGRac) that involves laborious sample processing. High prevalence of riboflavin deficiency (EGRac ≥ 1.4) and suboptimal status (EGRac of 1.3–1.39) have been reported in the UK and Ireland; yet the functional significance is unclear. Plasma riboflavin concentration may serve as an alternative indicator; its association with related metabolites has not yet been investigated. Secondary analysis was conducted to determine the change-point of plasma riboflavin with EGRac, to derive a reference interval for plasma riboflavin, and to determine the association of riboflavin status with plasma PLP, using data of 223 older adult women from a cross-sectional study. Fasting blood samples and sociodemographic, anthropometric and dietary data were available for a convenience sample of 223 older adult women. Plasma PLP and related metabolites were quantified using isotope-dilution liquid chromatography-tandem mass spectrometry. The change-point (95% CI) between EGRac and plasma riboflavin occurred at plasma riboflavin concentration of 26.5 (20.5; 32.5) nmol/L (with EGRac of 1.25). The median (IQR) plasma riboflavin concentration was 15.7 (11.2, 23.8); and the upper and lower limits (90%CI) of the central 95% reference interval were 6.70 (6.33, 7.79) and 64.2 (55.0, 74.6) nmol/L, respectively. Plasma PLP (geometric mean (95%CI)) was significantly lower in women with riboflavin deficiency, 54.0 (46.8, 62.2) nmol/L (n = 64), and suboptimal riboflavin status, 56.1 (48.9, 64.3) nmol/L (n = 48), compared to those with riboflavin adequacy, 135 (112, 161) nmol/L (n = 110). Plasma PLP was positively associated with plasma riboflavin concentration after adjustment for total B6 intake, age, ethnicity, BMI, education, household income and C-reactive protein concentration [β (95% CI) = 1.92 (.670, 3.17) nmol/L; p = 0.003]; a significant interaction between plasma riboflavin and total dietary B6 intake was observed (p = 0.024). In conclusion, we are presenting for the first time a reference range for plasma riboflavin concentration and its change-point with EGRac in healthy women. Vitamin B6 status is strongly associated with riboflavin status; more research is needed to elucidate this relationship in a larger sample and ideally intervention study.

Vitamin B2-sensitized degradation of the multifunctional drug Evernyl, in the presence of visible light – microbiological implications

2015 ◽  
Vol 87 (9-10) ◽  
pp. 997-1010 ◽  
Author(s):  
Carolina Gambetta ◽  
Walter A. Massad ◽  
Andrea V. Nesci ◽  
Norman A. García
Keyword(s):  
Antimicrobial Activity ◽  
Visible Light ◽  
Vitamin B2 ◽  
Singlet Molecular Oxygen ◽  
Time Resolved ◽  
Superoxide Radical Anion ◽  
Androgen Receptor Antagonist ◽  
Light Absorber ◽  
Electronically Excited ◽  
Triplet Excited States

AbstractTaking into consideration the importance of the photooxidative effects in complex bio- environments, this paper reports on the visible-light-promoted interactions between Evernyl (methyl 2, 4-dihydroxy-3,6-dimethylbenzoate, Ev) and vitamin B2 (riboflavin, Rf). Ev is a phenolic derivative, transparent to visible light, that possesses important antimicrobial activity. This compound is the first known natural, complete and specific human androgen receptor antagonist. Ev is profusely employed in personal-care products and synthesized as a secondary metabolite by several lichen and plant species. In both sceneries, acting Ev as a cosmetic component for topic applications or as a lichen constituent, may Rf behave as a native visible-light absorber pigment. In this context, kinetic and mechanistic aspects of the Rf-sensitized photooxidation of Ev, has been studied in aqueous solution, irradiating with blue LED light (463–471 nm) and employing stationary and time resolved methods. Results indicate that Ev reacts with the photogenerated reactive oxygen species (ROS) singlet molecular oxygen with a rate constant of kr=1.1±0.2×106 M−1s−1. In parallel Ev also quenches the electronically excited singlet and triplet excited states of Rf with rate constants close to the difussion limit. As a result the ROS superoxide radical anion and hydrogen peroxide are generated and the latter subsequently reacts with Ev. Possible implications of these photoreactions on the antimicrobial activity of Ev have been investigated employing a Candida albicans (CA) strain, isolated from human skin infection. The simultaneous presence of Rf, Ev in a sub-MIC, and blue-light irradiation produced a significant antimycotic effect, attributed to ROS photogeneration.

scholarly journals Antioxidant capacity of (+)-catechin visible-light photoirradiated in the presence of vitamin B2

Redox Report ◽  
2016 ◽  
Vol 22 (6) ◽  
pp. 282-289 ◽  
Author(s):  
M. G. Barua ◽  
J. P. Escalada ◽  
M. Bregliani ◽  
A. Pajares ◽  
S. Criado
Keyword(s):  
Visible Light ◽  
Antioxidant Capacity ◽  
Vitamin B2

Vitamin B2-Initiated Hydroxyl Radical Generation under Visible Light in the Presence of Dissolved Iron

2015 ◽  
Vol 3 (8) ◽  
pp. 1756-1763 ◽  
Author(s):  
Fang Xu ◽  
Xiang-Ning Song ◽  
Guo-Ping Sheng ◽  
Hong-Wei Luo ◽  
Wen-Wei Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Hydroxyl Radical ◽  
Vitamin B2 ◽  
Dissolved Iron ◽  
Radical Generation

scholarly journals Riboflavin, Flavin Mononucleotide, and Flavin Adenine Dinucleotide in Human Plasma and Erythrocytes at Baseline and after Low-Dose Riboflavin Supplementation

2002 ◽  
Vol 48 (9) ◽  
pp. 1571-1577 ◽  
Author(s):  
Steinar Hustad ◽  
Michelle C McKinley ◽  
Helene McNulty ◽  
Jørn Schneede ◽  
JJ Strain ◽  
...  
Keyword(s):  
Low Dose ◽  
Intervention Study ◽  
Flavin Adenine Dinucleotide ◽  
Plasma Concentrations ◽  
Flavin Mononucleotide ◽  
Vitamin B2 ◽  
Double Blind ◽  
Median Plasma ◽  
Activation Coefficient ◽  
Made In

Abstract Background: Vitamin B2 exists in blood as riboflavin and its cofactors, flavin mononucleotide (FMN) and FAD. The erythrocyte glutathione reductase activation coefficient (EGRAC) has traditionally been used to assess vitamin B2 status in humans. We investigated the relationships of EGRAC and plasma and erythrocyte concentrations of riboflavin, FMN, and FAD in elderly volunteers and their responses to riboflavin administration. Methods: EGRAC and plasma and erythrocyte concentrations of riboflavin, FMN, and FAD were determined in 124 healthy individuals with a mean age of 69 years. The same measurements were made in a subgroup of 46 individuals with EGRAC ≥1.20 who participated in a randomized double-blind 12-week intervention study and received riboflavin (1.6 mg/day; n = 23) or placebo (n = 23). Results: Median plasma concentrations were 10.5 nmol/L for riboflavin, 6.6 nmol/L for FMN, and 74 nmol/L for FAD. In erythrocytes, there were only trace amounts of riboflavin, whereas median FMN and FAD concentrations were 44 and 469 nmol/L, respectively. Erythrocyte FMN and FAD correlated with each other and with EGRAC and plasma riboflavin (P <0.05). All variables except plasma FAD responded significantly to riboflavin supplementation compared with placebo (P ≤0.04). The strongest increases were for riboflavin in plasma (83%) and for FMN in erythrocytes (87%). Conclusions: Concentrations of all B2 vitamers except plasma FAD are potential indicators of vitamin B2 status, and plasma riboflavin and erythrocyte FMN may be useful for the assessment of vitamin B2 status in population studies.

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