Riboflavin Concentration Research Articles

The implementation of drug reposition for alcoholic hepatitis based on a sub-pathway integration strategy.

BackgroundAlcoholic hepatitis (AH) is one of the most severe forms of liver disease. The therapies which are currently available are not entirely effective, and thus novel therapies are urgently needed. However, the development of these novel therapies is limited due to incomplete information about the molecular mechanisms involved in AH.MethodsThe microarray data (GSE28619) was downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) between the AH and the control samples were identified using the significant analysis of microarrays (SAM) method. Metabolic sub-pathways were identified using the SubpathwayMiner R package. Cell Counting Kit-8 (CCK-8) was used to evaluate the cell viability of AML-12 cells treated with different concentrations of ethanol or riboflavin. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were employed to show the hepatocyte function.ResultsA total of 1,041 genes were determined to be expressed differentially. We then identified 11 metabolic sub-pathways that could be involved in the development of AH. This was followed by a final integrated analysis of the sub-pathways involved in AH as well as the sub-pathways involved in the drug-affected cases. The final integration results led to the identification of 64 small molecular drugs. A potential novel drug (riboflavin) involved in the fatty acid metabolism pathway was identified for further investigation. Riboflavin at the 60 nM for 24 h could reverse ethanol-induced AML-12 cell injury and could markedly decrease ALT and AST activity. The decrease in the activities of these two enzymes was observed in a dose-dependent manner when it was compared to ethanol alone, which suggests that riboflavin has a protective effect against liver cell injury caused by alcoholism.ConclusionsTo summarize, the candidate agents which are identified in the present study might give practitioners insight into the development of novel therapeutic approaches for AH.

Improvement of myofibrillar protein gel strength of Scomberomorus niphonius by riboflavin under UVA irradiation.

In this study, effects of different concentrations of riboflavin (0, 0.02, and 0.1 μmol/g protein) on myofibrillar protein (MP, Scomberomorus niphonius) gel were characterized. The gel structure and properties were studied with or without Ultraviolet A (UVA) irradiation. Electron spin resonance results showed that riboflavin produced ·OH under UVA irradiation, which subsequently oxidized the MP. Compared with the control group, the addition of riboflavin with UVA irradiation increased the strength of the MP gel. The rheological results showed that under UVA irradiation, addition of riboflavin facilitated the sol-gel transition between 45 and 52°C, indicating that oxidation led to significant structural changes which in turn resulted in a more compact and uniform gel network. The presence of riboflavin led to increased carbonyl content and decreased sulfhydryl and free amino groups, which decreased the protein solubility and promoted alpha-helical conformational loss in the secondary structure of the MP. These results all indicated that the MP has been oxidized. Electrophoresis revealed that myosin heavy chains were aggregated in the UVA-treated riboflavin-added MP gel, indicating that protein cross-linking has been induced. All the results indicated that the ·OH produced by riboflavin under UVA irradiation oxidized the MP, and improved protein crosslinking and gel properties.

Elevated and rapid voltammetric sensing of riboflavin at poly(helianthin dye) blended carbon paste electrode with heterogeneous rate constant elucidation

The potent, selective, and consistent electrochemically polymerized helianthin dye modified carbon paste electrode (PHLDMCPE) was generated for the assessment of the significant antioxidant riboflavin (RL) with ascorbic acid (AA) and tyrosine (TR) using cyclic voltammetric (CV) and differential pulse voltammetric (DPV) techniques. The PHLDMCPE explicates a superior electrocatalytic resolution for the redox activity of 1 × 10−4 M RL in 0.1 M phosphate buffer solution (PBS) of pH 7.0 than the bare carbon paste electrode (BCPE). The oxidation peak current of RL and concentration of RL were attained linearly in the range of 60 µM to 150 µM with the lower limit of detection (LOD) of 4.02 × 10−8 M and the limit of quantification (LOQ) of 13.42 × 10−8 M, respectively. The heterogeneous rate constant for the equipped sensor was detected for RL at variable scan rates. This work conveys a modest and advisory methodology for the concurrent investigation of RL with AA and TR. The studied CV technique and developed sensor were adopted for the assessment of RL in pharmacological medication as a real sample. Electrochemically polymerized HLD modified carbon paste electrode was exposed for the evaluation of antioxidant riboflavin in both real and commercial samples in optimum circumstances using CV and DPV techniques. The selective resolution and interference study of riboflavin were done with ascorbic acid and tyrosine. The surface morphology of modified and unmodified carbon sensors was studied using FE-SEM and CV methods. The modified sensor exposes refined stability, reproducibility, and repeatability with a low LOD (4.02 × 10−8 M).

The Effect of Riboflavin Concentration, Antioxidant Activity, and Chromaticity on Craft Beer Photooxidation

The Effect of Riboflavin Concentration, Antioxidant Activity, and Chromaticity on Craft Beer Photooxidation

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

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.

Optimization of riboflavin production by Rhodotorula glutinis using statistical design

Background and objective Riboflavin is considered a significant nutritional and growth factor in humans, animals, plants, and microorganisms. This water-soluble vitamin is an intrinsic component of the basic metabolic processes and is a precursor of the oxidation-reduction coenzymes, flavin mononucleotide and flavin adenine dinucleotide. Riboflavin was synthesized by different microorganisms such as Ashbya gossypii, Eremothecium ashbyii, Candida famata, and Bacillus subtilis. The factors controlling riboflavin production, such as environmental and nutritional factors, were implemented to increase the yield of riboflavin. A statistical experimental design, such as the Plackett–Burman, enables the finding out of the most effective factors that increase the yield of riboflavin. Materials and methods One-factor-at-a-time approach was used to evaluate the effect of different nitrogen and carbon sources for riboflavin production by a local yeast isolate Rhodotorula glutinis. To optimize the riboflavin production by R. glutinis, the combined effects of seven variables (lactose, yeast extract, KH2PO4, MgSO4, time, pH, and rpm) were assessed using the Plackett–Burman design. Results and conclusion A preliminary medium formulation trial suggested that yeast extract and lactose were the appropriate nitrogen and carbon sources, respectively. The two-level Plackett–Burman design was implemented to study the nutritional and environmental factors for riboflavin production. Among the seven variables tested, lactose, KH2PO4, and rpm were identified as the most significant factors. The optimal levels of the three variables were determined by response surface methodology based on the Box–Behnken design. The validity of the model developed was verified, and the maximum riboflavin concentration was 88.25 μg/ml, representing 1.27 folds higher in the improved medium.

Rapid Quantification of Riboflavin in Milk by Front-Face Fluorescence Spectroscopy: A Preliminary Study.

The front-face fluorescence spectroscopy technique was used to establish a rapid prediction model of riboflavin concentration in milk without prior sample preparation. The prediction model developed was then compared with two conventional high performance liquid chromatography (HPLC)-based quantification methods. The method of standard addition allowed detecting a linear correlation between fluorescence intensity and riboflavin concentration in 12% (w/w) reconstituted low-heat milk powder. Validation of the model yielded an R2 of 0.99 with a standard error of prediction of 0.13 mg/L. The results suggest a potential use of front-face fluorescence spectroscopy as a simple method for off- and in-line determinations of riboflavin in milk.

Riboflavin and thiamine content in extracts of wild-grown plants for medicinal and cosmetic use

Products derived from wild-grown plants represent a growing segment of the modern pharmaceutical industry. In recent years, particular attention has been paid to their application in the cosmetic industry. The content of B group vitamins in these products is important because they affect the quality of the skin, hair and nails. The determination of thiamine and riboflavin in natural products is not so simple, as it requires complex sample preparation procedures and very sensitive analytical methods. In this paper, the HPLC method with fluorescence detection was applied to the determination of riboflavin and thiamine in the aqueous, ethanol and methanol extracts of elderberry, rosehip, rowanberry, wild garlic and blackthorn. Also, the influence of the extraction solvents on the vitamin’s concentration in obtained extracts was examined. It was found that the content of these vitamins in aqueous extracts is higher than that in alcoholic extracts. Riboflavin concentrations were in the range of 0.84–20.4 μg/g of the dry extract, while thiamine levels were from 0.06 to 0.67 μg/g of the dry extract. The highest riboflavin concentration was found in wild garlic extract followed by rosehip and elderberry extracts. On the other hand, thiamine content was higher in elderberry extract, while in rosehip it was not detected. In this work, the content of riboflavin and thiamine was determined for the first time in extracts of wild garlic, elderberry and rowanberry.

Genetic Algorithms-Based Approach for Wavelength Selection in Simultaneous Spectrofluorimetric Determination of Ofloxacin and Riboflavin in biological samples by Partial Least-Squares

This study shows that genetic algorithm (GA) is a suitable method for selecting wavelengths for partial least squares (PLS) calibration of mixtures with almost identical spectra without loss of prediction capacity employing spectrofluorimetric method. A training set of mixtures containing different concentrations of ofloxacin (OFL) and riboflavin (B2) were prepared to be used as calibration set to check the prediction ability of GA-PLS models due to spectral overlapping of these constituents. Each model was validated using a validation set and then real samples were analyzed. Linear calibration curves were obtained in the 0.5-5.0 and 2.0-10.0 µg mL-1 range for ofloxacin and riboflavin, respectively. To preprocess the data matrices, the orthogonal signal correction (OSC) was used and the analysis results were statistically compared. The methods accuracy for simultaneous determination of ofloxacin and riboflavin, were evaluated by the root mean square errors of prediction (RMSEP) which were 0.0868 and 0.158 for ofloxacin and riboflavin, respectively, and relative standard error of prediction (RSEP) which were 2.738 and 2.846 for ofloxacin and riboflavin, respectively using OSC-GA-PLS models. This procedure allows the simultaneous determination of OFL and B2 in human urine and serum samples with good reliability of the determination.

Novel riboflavin/VE-TPGS modified universal dentine adhesive with superior dentine bond strength and self-crosslinking potential

ObjectiveTo modify a universal dentine adhesive with different concentrations of riboflavin and D-Alpha 1000 Succinate polyethylene (VE-TPGS) as a chemical enhancer and to assess the micro-tensile bond strength (24h/12 months), determine resin penetration, measurement of intermolecular interactions and cytotoxicity. Materials and methodsAn experimental adhesive system based on bis-GMA, HEMA and hydrophobic monomer was doped with RF0.125 (RF – Riboflavin) or RF/VE-TPGS (0.25/0.50) and submitted to μTBS evaluation. Resin dentine slabs were prepared and examined using SEM and TEM. Adhesion force was analysed on ends of AFM cantilevers deflection. Quenched peptide assays were performed using fluorescence scanner and wavelengths set to 320nm and 405nm. Cytotoxicity was assessed using human peripheral blood mononuclear cell line. Molecular docking studies were carried out using Schrödinger small-molecule drug discovery suite 2018-2. Data from viable cell results was analyzed using one-way ANOVA. Bond strength values were analysed by two-way ANOVA. Nonparametric results were analyzed using a Kruskal–Wallis test at a 0.05 significance level. ResultsRF/VE-TPGS0.25 groups showed highest bond strength results after 24-h storage in artificial saliva (p<0.05). RF/VE-TPGS0.50 groups showed increased bond strength after 12-months of ageing. RF/VE-TPGS modified adhesives showed appreciable presence of a hybrid layer. Packing fraction indicated solid angle profiles describing well sized density and topology relations for the RF/VE-TPGS adhesives, in particular with the RF/VE-TPGS0.50 specimens. Qualitative analysis of the phenotype of macrophages was prominently CD163+ in the RF/VE-TPGS0.50. Both the compounds showed favourable negative binding energies as expressed in terms of ‘XP GScore’. ConclusionNew formulations based on the incorporation of RF/VE-TPGS in universal adhesives may be of significant potential in facilitating penetration, distribution and uptake of riboflavin within the dentine surface.

Impact of freeze-drying and subsequent storage on milk metabolites based on 1H NMR and UHPLC-QToF/MS

This study is the first to investigate the effect of freeze-drying on raw milk metabolites using untargeted metabolomics. To detect as many metabolites as possible in the liquid fractions, a multiplatform metabolomics approach was implemented using both NMR and MS-based techniques. The chemical fingerprint of freeze-dried milk powder was monitored during storage at three temperatures (room temperature, 4 °C, −20 °C) for up to 224 days. This study demonstrated that freeze-drying was an efficient means of drying milk resulting in only minor changes to the metabolites. With respect to storage, freeze-dried milk powders stored at 4 °C and −20 °C exhibited a stable metabolome while samples stored at 20 °C resulted in a clear change. During ambient storage, the concentrations of orotic acid, riboflavin and acetyl-carbohydrate reduced while those of fatty acids, threonic acid and uridine increased. The results from this study provide the foundation for experiment design and marker selection for further studies on milk metabolomics.

Fluorophotometric Determination of Riboflavin Concentrations in a Human Artificial Anterior Chamber Model.

PurposeCorneal cross-linking (CXL) requires an adequate corneal riboflavin impregnation, which is clinically assessed by verification of a riboflavin “flare” in the anterior chamber. We set out to replace this subjective assessment with an objective measurement method and evaluated fluorophotometry as an apparatus-based technique for riboflavin detection in the anterior chamber.MethodsIn an artificial anterior chamber model using human corneas and a modified Fluorotron fluorophotometer, we determined the detection limits of riboflavin concentrations across native corneas by comparison measurements of the same concentrations in glass cuvettes. Subsequently, standard CXL procedures with corneal application of riboflavin were simulated and the proportions of riboflavin entering the anterior chamber were measured fluorophotometrically.ResultsThe measurement results of the riboflavin dilution series in the artificial anterior chamber showed a very high concordance with the results obtained in a glass cuvette (Pitman test P = 0.329). In the CXL simulation, the mean riboflavin concentration measured in the anterior chamber increased within 15 minutes from 5 (±1) to 903 (±204) ng/mL and stood at 1089 (±56) ng/mL after 30 minutes.ConclusionsFluorophotometry is able to measure riboflavin in an artificial anterior chamber across human corneas over a wide range of concentrations and it reliably detects the increasing riboflavin signal in simulated CXL procedures.Translational RelevanceThe replacement of the subjective riboflavin detection by a technically straightforward, objective detection method might increase patient safety and treatment efficiency in CXL.

Increase in efficacy of near-infrared femtosecond micromachining in ophthalmic hydrogels with the addition of sodium fluorescein, rose bengal, and riboflavin.

We report on the effect of exogenous doping agents with large two-photon absorption cross sections on the efficacy of near-infrared femtosecond micromachining in ophthalmic hydrogels. Contaflex GM Advance 58 hydrogels were solution doped in low concentrations of sodium fluorescein, rose bengal, and riboflavin dissolved in balanced salt solution prior to femtosecond micromachining with three near-infrared wavelengths: 720, 800, and 1035 nm. Using any of the three doping agents in the concentrations studied produced an increase in the amount of optical phase change induced in the material at all writing wavelengths and reduced the amount of power needed to induce a desired amount of phase change.

Riboflavin and lumichrome exuded by the bacterium Azospirillum brasilense promote growth and changes in metabolites in Chlorella sorokiniana under autotrophic conditions

The effects of riboflavin and its degradation compound, lumichrome, produced by Azospirillum brasilense on the growth and production of carbohydrates, lipids, and pigments in Chlorella sorokiniana were analyzed. A. brasilense is able to produce and release riboflavin from the first 24h of incubation in Synthetic Growth Medium (SGM). Synchronic peaks of lumichrome and riboflavin suggest that the former originates from the photodegradation of the latter. The constant growth of bacterial population indicated that riboflavin and lumichrome are cell density-independent. In this study, riboflavin showed a higher effect on the population growth of Chlorella than did lumichrome. The effects of synthetic riboflavin and lumichrome on microalgae were dependent on the concentration of these compounds in the culture media. Lower concentrations of riboflavin (1ngmL−1 or 10ngmL−1) enhanced the growth of C. sorokiniana, while the highest amount of riboflavin (100ngmL−1) showed no effect. Synthetic riboflavin and lumichrome significantly increased the production of carbohydrates compared to the basal medium. Lumichrome showed the highest production of carbohydrates at 48h while riboflavin at 96h. Pigments were significantly more affected by the presence of lumichrome than by riboflavin. Enhanced growth and production of carbohydrates and pigments in C. sorokiniana grown in exudates of A. brasilense, suggests a synergistic effect of the riboflavin and lumichrome produced and exuded by this bacterium.

Ultrasensitive and reusable upconversion-luminescence nanofibrous indicator paper for in-situ dual detection of single droplet

Traditional indicator paper is disposable after use, requires a large number of target solutions and can only detect one item. In this study, recyclable upconversion-fluorescence indicator papers consist of upconversion nanorods and plasmonic nanostructures are fabricated by electrospinning. Human-body fluids containing different riboflavin concentration and pH are used as target solution, because these two items are usually detected in clinic to distinguish ambiguous diseases but often performed by two different testing processes that inevitably need more target solutions. Significantly different from conventional detecting system, this recyclable indicator paper can simultaneously achieve riboflavin and pH detections by using only a single droplet of target solution. As low as 0.01 ppm riboflavin can be sensitively detected, which is superior to most reported detection limit of fluorescence sensor. Moreover, this indicator paper can detect a single droplet (~10 μl) rather than a large amount of target solution (>1 ml) needed by traditional detecting system, and the pH can also be simultaneously in-situ detected using the same indicator paper. After the detection, the target solution is easily removed so that it brings about excellent recyclability, which is another advantage over traditional detecting system.

Micronutrient intakes of lactating mothers and their association with breast milk concentrations and micronutrient adequacy of exclusively breastfed Indonesian infants

ABSTRACTBackgroundBreast milk is the sole source of nutrition for exclusively breastfed infants in the first 6 mo of life, yet few studies have measured micronutrient concentrations in breast milk in light of maternal diet and subsequent infant micronutrient intakes.ObjectivesWe evaluated the adequacy of micronutrient intakes of exclusively breastfed Indonesian infants by measuring milk volume and micronutrient concentrations and assessed maternal micronutrient intakes and their relationship with milk concentrations.MethodsMother–infant (2–5.3 mo) dyads (n = 113) were recruited for this cross-sectional study. Volume of breast-milk intake via the deuterium dose-to-mother technique over 14 d and analyzed micronutrient concentrations were used to calculate micronutrient intakes of exclusively breastfed infants. Maternal 3-d weighed food records were collected to assess median (IQR) micronutrient intakes. Multivariate regression analyses examined the association of usual maternal micronutrient intakes with milk micronutrient concentrations after adjustment for confounding variables.ResultsMean ± SD intake of breast-milk volume was 787 ± 148 mL/d. Median daily infant intakes of iron, zinc, selenium, magnesium, sodium, and B-vitamins (thiamin, riboflavin, niacin, pantothenic acid, B-6, and B-12) were below their respective Adequate Intakes. Inadequacies in maternal intakes (as % < estimated average requirements) were >40% for calcium, niacin, and vitamins A, B-6, and B-12. Significant positive associations existed between maternal usual intakes of vitamin A, niacin and riboflavin and milk retinol, nicotinamide, and free riboflavin concentrations in both unadjusted and adjusted (for infant age, milk volume, and parity) analyses (all P < 0.05).ConclusionsThe majority of micronutrient intakes for these exclusively breastfed infants and their mothers fell below recommendations, with associations between maternal intakes and breast-milk concentrations for 3 nutrients. Data on nutrient requirements of exclusively breastfed infants are limited, and a better understanding of the influence of maternal nutritional status on milk nutrient concentrations and its impact on the breastfed infant is needed.

Identification and clinical significance of Bordetella holmesii isolated from a rare case of bacteremia in Nantong China

Objective To analyze the identification, drug resistance and clinical significance of a rare bacterium of Bordetella holmesii (B.holmesii) to improve its detection and clinical diagnosis and treatment. Methods A strain isolated from a bacteremia case was identified by bacterial culture, biochemical tests and 16S rRNA gene sequencing. Mega 7.0 software was used to conduct a similarity analysis of 16S rRNA gene sequences between the type strains of Bordetella spp. and the isolate, and then a phylogenetic tree was constructed. Antibiotic resistance of the isolate was determined by E-test. Changes in bacterial growth were measured after adding different concentrations of riboflavin or its inhibitor lumiflavin to the culture medium. Results B. holmesii ABD2 was the pathogen causing bacteremia in the immunocompetent patient. It was deposited under the number of CGMCC 1.13721 in China General Microbiological Culture Collection Center (CGMCC), and the 16S rRNA gene sequences were deposited in National Center for Biotechnology Information (NCBI) with the accession number of KT828544.1. Unrooted tree showed that the B. holmesii strain was highly homologous with B. pertussis. Antibiotic susceptibility test showed that the minimum inhibitory concentrations (MIC) of piperacillin, ceftazidime, cefepime, imipenem, meropenem, ciprofloxacin, levofloxacin, gentamicin, amikacin, erythromycin, tetracycline and polymyxin B against the isolate were low, while the MIC values of cefazolin, cefuroxime, cefoxitin, cefotaxime, aztreonam and trimethoprim-sulfamethoxazole were high. Riboflavin accelerated the growth of B. holmesii ABD2, while its inhibitor lumiflavin had an inhibitory effect. Conclusions As B. holmesii is hard to isolate and identify, limited clinical, microbiological and epidemiological data are available. It is an under-recognized pathogen with a considerable amount of information that remains to be studied. Key words: Bordetella holmesii; Bacteremia; Immunocompetence; 16S rRNA gene sequencing; Riboflavin; lumiflavin

Water compatible molecularly imprinted polymer for controlled release of riboflavin as drug delivery system

In this study, facile and green method for synthesis of imprinted material was introduced which subsequently applied for efficient delivery of Riboflavin (vitamin B2). Characterization of the prepared polymer was carried out by the Fourier Transform Infrared (FT-IR) spectroscopy and Scanning Electron Microscopy (SEM). The weight ratio of functional monomer to template over 5–20 W/W% was evaluated in order to find the best loading condition and subsequent release into synthetic biomimetic media namely simulated body fluid (SBF) and media including 1% NaCl solution, simulated gastric fluid (SGF) solution at pH 1.5 and the solution of 1% W/W Na2SO4. Under optimized condition, the highest value of released riboflavin was achieved at 1:20 ratio of riboflavin to polymer in NaCl (55.07%) media which providing that the body requirement about 5 days of this vitamin between minimum effective concentration (MEC) and maximum safe concentration (MSC) of Riboflavin in short release time (45 min). Moreover, the experimental data were fitted to Higuchi model in order to calculate Higuchi solubility constant.

Lumiflavin increases the sensitivity of ovarian cancer stem-like cells to cisplatin by interfering with riboflavin.

Here, we used lumiflavin, an inhibitor of riboflavin, as a new potential therapeutic chemosensitizer to ovarian cancer stem‐like cells (CSCs). This study demonstrates that the enrichment of riboflavin in CSCs is an important cause of its resistance to chemotherapy. Lumiflavin can effectively reduce the riboflavin enrichment in CSCs and sensitize the effect of cisplatin Diamminedichloroplatinum (DDP) on CSCs. In this study, CSCs of human ovarian cancer cell lines HO8910 were separated using a magnetic bead (CD133+). We also show the overexpression of the mRNA and protein of riboflavin transporter 2 and the high content of riboflavin in CSCs compared to non‐CSCs (NON‐CSCs). Moreover, CSCs were less sensitive to DDP than NON‐CSCs, whereas, the synergistic effect of lumiflavin and DDP on CSCs was more sensitive than NON‐CSCs. Further research showed that lumiflavin had synergistic effects with DDP on CSCs in increasing mitochondrial function damage and apoptosis rates and decreasing clonic function. In addition, we found that the combination of DDP and lumiflavin therapy in vivo has a synergistic cytotoxic effect on an ovarian cancer nude mice model by enhancing the DNA‐damage response and increasing the apoptotic protein expression. Notably, the effect of lumiflavin is associated with reduced riboflavin concentration, and riboflavin could reverse the effect of DDP in vitro and in vivo. Accordingly, we conclude that lumiflavin interfered with the riboflavin metabolic pathways, resulting in a significant increase in tumour sensitivity to DDP therapy. Our study suggests that lumiflavin may be a novel treatment alternative for ovarian cancer and its recurrence.

Light-induced reactions of methionine and riboflavin in model wine: Effects of hydrolysable tannins and sulfur dioxide

The riboflavin-mediated photo-degradation of methionine in white wine has been related to onset of undesired light-struck taste. This research investigated the effects of different concentrations of riboflavin and methionine, hydrolysable tannins from various sources (nut galls, chestnut and oak woods) and sulfur dioxide on methionine degradation in a model wine exposed to light. Increased methionine concentration resulted in its increased degradation with the consequent formation of volatile sulfur compounds, namely methanethiol, dimethyl disulphide and dimethyl trisulphide. Tannins, especially nut gall tannin, were effective in limiting both methionine degradation and the production of volatile sulfur compounds. Sulfur dioxide enhanced the methionine degradation although the light-struck taste was not perceived when sulfur dioxide concentration was higher than 50 mg/L. In conclusion, the use of hydrolysable tannins can represent a promising tool for protecting white wine against the light-struck taste also limiting the use of sulfur dioxide.