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Objective of this study was to investigate the changes of oxidative stress parameters in Chinese hamster ovary (CHO) cells exposed to xanthene food dyes (erythrosine and phloxine), commonly-used azo dyes in the food industry. For this purpose, glutathione (GSH) and malondialdehyde (MDA) levels, glutathione peroxidase (GPx) and catalase (CAT) activity measurements of CHO cells treated with erythrosin (50 µM) and phloxine (40 µM) were compared with the control group. There was no significant difference between MDA levels in CHO cells exposed to both dyes and control group (p > 0.05), however GSH levels significantly decreased with dye addition (p ≤ 0.05). An increase in GPx activity of the CHO cells exposed to phloxin was observed (p ≤ 0.05). However, there was no change in GPX activity of erythrosin-exposed CHO cells (p > 0.05). In terms of CAT activity, difference between the dye-added cells and the control group was not observed. Consequently, decrease in level of GSH, which one of major antioxidant components in the cell, suggests that erythrosine and phloxine can have a toxic effect.

A simple, rapid, highly sensitive and selective non-extraction spectrophotometric and sequential injection analysis with lab-at-valve (SIA-LAV) methods for the determination of bismuth(III) have been developed based on the formation of a specific ion association complex (IA) between tetraiodobismuthate(III) anion and the polymethine dye Astra Phloxine (AP). The changes in the absorption spectra resulting from the formation of the IA are explained in the framework of the exciton theory by the aggregation of dye ions. The analytical wavelength was chosen in the region of an intense narrow bathochromically shifted band with maximum at 600 nm related to the band of the aggregated dye in a specific IA. It was shown that any cationic dye, including representatives of triphenylmethane, rhodamine and polymethine dyes, is capable of forming specific IAs. One of the most important prerequisites for the formation of a specific IA is its relatively low solubility. The UV-visible spectrum of the AP cation was calculated using the time-dependent density functional theory (TD-DFT). Superiority of the TD-DFT with the Franck-Condon approximation, which takes into account vibronic effects, was shown over the traditional non-vibrationally resolved TD-DFT calculations. The PBE1PBE functional is the most suitable in comparison with the used M06, CAM-B3LYP, WB97XD and M11 functionals. Carrying out the chemical reaction and mixing in an external mixing chamber allowed the mixing conditions to be adapted to the requirements necessary for the complete formation of the specific IA. Thus, the maximum possible sensitivity was achieved, which was about an order of magnitude higher than when using the classical SIA approach. Calibration ranges and detection limits (indicated in parentheses) for the developed spectrophotometric and SIA-LAV procedures were 0.04-0.5 (0.01) and 0.1-1.7 (0.03) µg L−1, respectively. The molar absorptivity and Sandell's sensitivity were found to be 6.6 × 104 mol−1 L cm−1 and 3.16 × 10−3 μg cm−2, respectively. The proposed methods were successfully applied for the determination of bismuth content in pharmaceutical compositions and alloys.

A novel, simple, sensitive and selective method for the spectrophotometric determination of ascorbic acid (Asc) has been developed. The developed method is based on the redox-reaction between Asc and triiodide ions (I3−) and vortex-assisted liquid-liquid microextraction (VALLME) of excess I3− as ion associate (IA) with polymethine dye Astra Phloxine FF (AP), with subsequent determination of IA spectrophotometrically at 560 nm. In the presence of Asc, discoloration of the extract of IA occurs. The influence of different factors was studied, and optimized conditions for the spectrophotometric determination of Asc were found: 4.0 · 10−6 mol L−1 I3−, 4.0 · 10−4 mol L−1 KI, 4.0 · 10−5 mol L−1 AP, 500 μL of carbon tetrachloride (ratio of volumes of aqueous and organic phases 10:1), vortexing for 15 s at 3000 rpm and centrifugation for 2 min at 2000 rpm. The determination of Asc is possible in the presence of many interferants: 20,000-fold amounts of tartaric, citric and malic acids and 10,000-fold amount of oxalic acid, over 2000-fold amounts of HCO3−, CH3COO−, HPO42−, SO42−, Cl−, F−, Na+, K+, Li+, Ca2+, Sr2+, Ni2+, Co2+ and Zn2+; and 5-fold amounts of Fe3+ and Cu2+. The organic acids (oxalic, tartaric, citric and malic acids) eliminate the effect of >100-fold amounts of Fe3+ and Cu2+. The calibration curve was linear in the range from 0.003–0.53 mg L−1 of Asc (R2 = 0.997); the limit of detection (n = 10, P = 0.95) was 0.89 μg L−1 of Asc, and the limit of determination (n = 10, P = 0.95) was 2.94 μg L−1 of Asc. The suggested procedure was successfully applied for the determination of Asc in food samples and model mixtures (RSD 2.1–3.9%, recovery 98.0–102.3%). The accuracy of the procedure was confirmed by analysis with a reference method.

Cosmetics are primarily applied to the skin; therefore, the association of cosmetic dyes with skin diseases or inflammation is a topic of great interest. Thymic stromal lymphopoietin (TSLP) is an interleukin 7-like cytokine that activates dendritic cells to promote Th2 inflammatory immune responses. TSLP is highly expressed in keratinocytes under inflammatory conditions, which suggests that it may play a critical role in the development of skin diseases, such as atopic dermatitis. Therefore, we investigated whether cosmetic dyes influenced the production of TSLP by keratinocytes. Phloxine O, also known as D&C Red No.27, is one of the most common red synthetic pigments and is widely used in colored cosmetics. Our results showed that Phloxine O downregulated phorbol 12-myristate 13-acetate-induced production of TSLP in a murine keratinocyte cell line (PAM212). Phloxine O also suppressed TSLP expression in KCMH-1 cells, which are mouse keratinocytes that constitutively produce high levels of TSLP. To investigate the in vivo effects of Phloxine O, we induced TSLP expression in mouse ear skin by topically applying MC903, a vitamin D3 analogue that is a well-known inducer of atopic dermatitis-like symptoms. Topical application of Phloxine O prevented MC903-induced TSLP production in mouse ear skin, attenuated the acute dermatitis-like symptoms and decreased serum IgE and histamine levels in mice. Suppression of TSLP expression by Phloxine O correlated with reduced expression of OX40 ligand and Th2 cytokines in mouse ear skin. Our results showed that Phloxine O may be beneficial to prevent dermatitis by suppressing the expression of TSLP and Th2 cytokines in skin.

β-cyclodextrin modified magnetite nanoparticles were synthesized by chemical co-precipitation method in a single step and were characterized by FT-IR, powder XRD, SEM, TEM, EDX and TGA data. The nano-sized composite was used as an efficient adsorbent material for the removal of eosin and phloxine dyes from the aqueous solution and the effect of different factors such as contact time and the amount of dosage have been studied on the adsorption process.

An bi-arsenic capped Well-Dawson arsenomolybdates supramolecular material, formulated as, {pyr}{Hbib}2{AsIII 2(OH)2AsV 2Mo18O62} (1) (pyr = pyrrole; bib = 1, 4-bis(1-imidazoly)benzene) has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, UV, XRD, and single-crystal X-ray diffraction. In the structure of 1, {As2Mo18O62} (abbreviated to {As2Mo18}) polyanions are capped by two disordered AsIII units which are distributed in six symmetric ditches of the {Mo3O13} group on two poles of the Dawson cluster with the occupation ratio of 0.5 and 0.25, respectively. Two kinds of caps: pyramidal-shaped {AsO3} and tetrahedron {AsO3(OH)} caps are formed via the combination of three u-O atoms from Dawson cluster or the same three u-O atoms and one hydroxyl with As centers. Compound 1 represents a brand new bi-capped Dawson structure, which shows good photocatalytic behaviors for degradation of recalcitrant dyes Azon Phloxine (AP). Moreover, compound 1 exhibits an effective inhibition effect on proliferation of Human hepatoma cells (HepG-2) for the synergetic effect of Dawson cluster and AsIII cap.

the photoactive compounds phloxine B and menadione are relatively safe food additives and possess efficient insecticidal properties against certain insect species. The two compounds were tested for toxicity to the peach fruit fly, Bactrocera Zonata (Saunders) under both dark and sunlight conditions. Both compounds had no significant toxic effect in dark and concentration-dependent toxicity when insect exposed to sunlight for 2 hrs. Phloxine B was approximately 1000 time more toxic to B. zonata than menadione with LC25 in the water of 0.0007 g% and 0.854 g% (w/v), respectively. Adding menadione to phloxine resulted in significant antagonistic effects on insect mortality, which could be due to menadione alteration of the pH of the feeding media and/or menadione induction of the ROS-detoxifying enzymes, particularly peroxidase. It is concluded that phloxine B and menadione are incompatible and their mixture is not likely to pose any significant addition to their control potential against B. zonata.

A new inorganic-organic open framework based on Wells-Dawson arsenomolybdate, {Ag(diz)2}3[{Ag(diz)2}3(As2Mo18O62)]∙H2O (1) (diz = 1,2-diazole) has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, UV, XRD, and single-crystal X-ray diffraction. In compound 1, each {As2Mo18} cluster uses six terminal oxygen atoms on 'equator' position to attract peripheral six {Ag(diz)2} linkers, which are further connected by six Dawson clusters located on two different planes via unique equator-to-equator interlaced ways to form a unprecedented 3D network with {812 ∙ 123}{8}3 topology. Compound 1 represents the highest covalent connectivity of 3-D Dawson arsenomolybdate, which exhibits merit photocatalytic properties for degradation of refractory dyes Azon Phloxine (AP) under UV light. In addition, compound 1 has a potent inhibition effect on proliferation of Human gastric adenocarcinoma cells (SGC-7901).

A fluorescent stain, calcofluor white (CFW), was used for detection of spores of the microsporidium Enterocytozoon hepatopenaei (EHP). EHP spores in suspension, in feces, or in the infected hepatopancreas of the shrimp Penaeus vannamei, can be easily stained with this chitin and cellulose binding dye to show distinct blue-white fluorescent oval walls. The dye does not stain the host tissues. EHP spores showed orange-red spots by staining with hematoxylin and phloxine (H&P) in the section. CFW staining provides a simple and rapid method for determining the presence of EHP spores in fecal or tissue samples.

For the first time an optical probe is proposed as the microdrop holder and simultaneously the measuring cell in a direct immersion single-drop microextraction (DI-SDME) procedure. This approach enables the analytical signal (absorbance of organic phase) to be monitored and recorded online during the extraction process. Based on the suggested approach, a novel on-probe DI-SDME method for the determination of thiocyanate ions using the extraction of the ion pair formed between SCN− and Astra Phloxine reagent in acidic medium into 40 µL of amyl acetate is suggested. The final experimental conditions were found to be: the pH of the aqueous phase being 3, the stirring rate at 500 rpm, a 150 s extraction time, the absorption maximum at 555 nm and 700 nm as the reference wavelength. The calibration plot was linear in the range of 0.29–4.35 mg L−1 of SCN−, with a correlation coefficient of 0.9981. The limit of detection (LOD) was found to be 0.12 mg L−1. The method was applied for analysis of human saliva samples. Furthermore, the possibility of using the optical probe not only for DI-SDME but also for liquid–liquid–liquid microextraction (LLLME) and reverse mode microextraction techniques is shown in separate experiments.

A novel vortex-assisted liquid-liquid microextraction (VA-LLME) for determination of iodide was developed. The method includes the oxidation of iodide with iodate in the presence of hydrochloric acid followed by VA-LLME of the ion-pair formed between ICl2(-) and Astra Phloxine reagent (AP) and subsequent absorbance measurement at 555nm. The appropriate experimental conditions were investigated and found to be: 5mL of sample, 0.27molL(-)(1) HCl, 0.027mmolL(-1) KIO3 as the oxidation agent, 250μL of extraction mixture containing amyl acetate as the extraction solvent and carbon tetrachloride as the auxiliary solvent (1:1, v/v), 0.04mmolL(-1) AP reagent, vortex time: 20s at 3000rpm, centrifugation: 4min at 3000rpm. The calibration plot was linear in the range 16.9-169μg L(-1) of iodide, with a correlation coefficient (R(2)) of 0.996, and the relative standard deviation ranged from 1.9 to 5.7%. The limit of detection (LOD) and limit of quantification (LOQ) were 1.75 and 6.01μgL(-)(1) of iodide, respectively. The suggested procedure was applied for determination of iodide in real mineral water samples.

The present study is dedicated to development of improved method for determination of trace amounts of fluorides in natural waters which is based on the interaction of fluorides with ion associate (IA) of Al(III), salicylic aldehyde acylhydrazones (benzhydrazone (SABH) and 4-picolinhydrazone (SAPH)) and polymethine dye Astra Phloxine FF (AP). Comparison of analytical forms [Al(SABH)2]⋅AP and [Al(SAPH)2]⋅AP showed that the analytical system Al(III)-SAPH-AP is more effective, namely, a higher level of preconcentration of the analytical form is ensured by and extraction equilibrium is achieved faster. Based on the study, we propose a new, fast, simple, reliable, sensitive, and accurate method of the indirect UV–Vis-spectrophotometric determination of fluorides grounded on the interaction of fluorides with IA of Al(III), SAPH and AP with the utilization of vortex-assisted liquid-liquid microextraction (VALLME). The method is based on the discoloration of the microextract of IA of Al(III), SAPH and AP (Al-SAPH-AP) in presence of fluoride ions due to the formation of fluoride complexes of aluminum with higher stability. The effect of various factors has been studied. The optimal conditions of the UV–Vis-spectrophotometric determination of fluorides were defined as: pH 7.0–10.0, 1.0⋅10−6 mol⋅L−1 Al(III); 4.0⋅10−5 mol⋅L−1 SAPH; 1.0⋅10−6 mol⋅L−1 AP; λ = 560 nm. VALLME have been carried out in 250 μL of CCl4 at 20:1 vol ratios of aqueous and organic phases, with vortexing at 3000 rpm for 15 s followed by centrifugation at 2000 rpm for 2 min. The determination of fluorides is feasible in the presence of various interferences. The calibration curve shows the linear dependence in the range of 0.3–114 μg⋅L−1 of the fluorides concentration (R2 = 0.993) with the limit of detection of 0.086 μg⋅L−1 and the limit of determination of 0.284 μg⋅L−1. The accuracy of the proposed protocol of fluorides determination was verified towards a reference method on the samples of natural rivers waters (RSD 2.6–3.1%, recovery 98.3–101.4%).

The recoveries of xanthene dyes in the analysis of acidic tar-dyes in high-protein foods were improved by loading them onto polyamide columns at pH 8.5, instead of using the conventional pH 3-4 solution. The experimental scale was reduced to approximately half that of the conventional method. Furthermore, instead of eliminating the organic solvent in the extract by evaporation, the extract was diluted with water prior to PA column cleanup in order to reduce the ratio of organic solvent so that acidic tar-dyes would be better retained on the column. The above two procedures shortened the operation time and allowed for a simpler protocol. With this method, the recoveries of erythrosine, phloxine, and rose bengal from salted cod roe were 82, 88, and 74%, respectively. The recovery percentages were greatly improved compared to those achieved by conventional column loading at pH 3.5 (26, 44, and 18%, respectively). The recoveries of azo-dyes (Amaranth, New Coccine, Allura Red AC, Tartrazine, Sunset Yellow FCF) were also improved from 41-66 to 79-99%.

A novel and simple procedure for determination of anionic surfactants has been developed. The method is based on the reaction of sodium dodecyl sulphate (SDS) with Astra Phloxine FF reagent at pH 3–8, followed by liquid–liquid microextraction of the formed ion associate into an organic phase containing a mixture of carbon tetrachloride and dichloroethane (4:1, v/v) and subsequent UV-Vis detection at 555 nm. The calibration plot was linear in the range 0.006–0.29 mg L−1 of SDS. The limit of detection (LOD), calculated based on 3s, is 0.002 mg L−1. The method was applied to the determination of anionic surfactants in real wastewater samples.

The aim of this study was to determine the presence, number, and morphometrical characteristics of Paneth cells (PC) in the small intestine of guinea pigs during lactation. We used 48 pups from 0 to 15 days old. Samples from small intestine were fixed in 10% buffered formaldehyde (pH 7.4) and processed for histological and morphometrical studies using hematoxylin and eosin (HE), Phloxine tartrazine or Masson's Trichome staining, or immunohistochemistry for lysozyme. PC were morphologically identified at day 2 using Masson's Trichome or Phloxine tartrazine stainings, and at day 4 using HE, whereas using immunohistochemistry they were recognized from birth. Morphometrical differences were found between the intestinal sections at each age studied, and within each section during the first weeks of life. In all developmental stage, the highest number of PC was observed in the duodenum of 13 days old guinea pigs. Our results confirm the presence of PC in the small intestine of guinea pigs from birth.

Ascorbic acid (AsA) is known as an antioxidant but concomitantly possesses a pro-oxidant property. Because the impact of AsA on photodynamic therapy response is unclear, we investigated the effect of AsA on photocytotoxicity induced by phloxine B in human acute promyelocytic leukemia HL-60 cells. AsA synergistically enhanced phloxine B-induced photocytotoxic effects, including inhibition of cell proliferation, DNA ladder formation, and caspase-3 activation, whereas AsA itself showed no photocytotoxicity. AsA also enhanced the consumption of the reduced glutathione level compared with the cells treated with phloxine B alone under the light condition. Combination of AsA with phloxine B under the light condition enhanced the phosphorylation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase (MAPK). These effects were completely cancelled by catalase. These results suggest that AsA synergistically enhances phloxine B-induced photocytotoxicity, possibly through the extracellular oxidative stress-dependent MAPK pathway activation.

Three modes of liquid–liquid based microextraction techniques – namely auxiliary solvent-assisted dispersive liquid–liquid microextraction, auxiliary solvent-assisted dispersive liquid–liquid microextraction with low-solvent consumption, and ultrasound-assisted emulsification microextraction – were compared. Picric acid was used as the model analyte. The determination is based on the reaction of picric acid with Astra Phloxine reagent to produce an ion associate easily extractable by various organic solvents, followed by spectrophotometric detection at 558 nm. Each of the compared procedures has both advantages and disadvantages. The main benefit of ultrasound-assisted emulsification microextraction is that no hazardous chlorinated extraction solvents and no dispersive solvent are necessary. Therefore, this procedure was selected for validation. Under optimized experimental conditions (pH 3, 7 × 10−5 mol/L of Astra Phloxine, and 100 μL of toluene), the calibration plot was linear in the range of 0.02–0.14 mg/L and the LOD was 7 μg/L of picric acid. The developed procedure was applied to the analysis of spiked water samples.

Our previous study revealed that the photo-irradiation of rose bengal, erythrosine, and phloxine, xanthene photosensitizers, used as dental plaque disclosing agents, could exert bactericidal action on planktonic Streptococcus mutans via the singlet oxygen. In the present study, the photo-irradiation induced bactericidal activity of the three xanthene compounds against the experimental biofilm of S. mutans was investigated in combination with acid electrolyzed water (AcEW) and alkaline electrolyzed water (AlEW). As a result, only the photo-irradiated rose bengal in AlEW showed prominent bactericidal activity with a >3-log reduction of the viable bacterial count. Since our previous study showed that the affinity of rose bengal to bacterial cells was superior to that of erythrosine and phloxine, it was speculated that AlEW damaged the extracellular matrix of the experimental biofilm, which would let the rose bengal easily be bound to the bacterial cells. From these results, it is strongly suggested that rose bengal is a suitable photosensitizer for use as a plaque disclosing agent in photodynamic antimicrobial chemotherapy to treat dental plaque.

The xanthene dyes, erythrosine, phloxine, and rose bengal, were adsorbed to charred cellulose granules. The charred cellulose granules were preliminarily steeped in ionic (NaOH, NaCl, KOH, KCl, and sodium dodecyl sulfate (SDS)), nonionic (glucose, sucrose, and ethanol), and amphipathic sucrose fatty acid ester (SFAE) solutions, and adsorption tests on the dye to the steeped and charred cellulose granules were conducted. Almost none of the dye was adsorbed when the solutions of ionic and amphipathic molecules were used, but were adsorbed in the case of steeping in the nonionic molecule solutions. Thin-layer chromatography (TLC) and the Fourier transform infra-red (FT-IR) profiles of SFAE which was adsorbed to the charred cellulose granules and extracted by ethyl ether suggested the presence of hydrophobic sites on the surface of the charred cellulose granules. We confirmed that the xanthene dyes could bind to the charred cellulose granules by ionic and hydrophobic bonds.

Complexation of dextran with the active sites of dextransucrase was used to produce dextran on a tube in a laminar flow. A dextransucrase solution was passed through a Teflon tube at flow rates of 10 and 50 mL/h to immobilize the enzyme on the inner surface of the tube, and then sucrose solution was passed through the enzyme-immobilized tube to form giant dextran particles. The Reynolds number during the procedure was 4 or 20. The distribution of dextran along the flow direction in the tube was determined colorimetrically and showed that the dextran formed was distributed such that the amounts of dextran were higher near the ends than in the middle section of the tube. Direct observation of the dextran after colorization with phloxine showed that giant dextran particles, up to approximately 20 μm in size, were formed. The distribution of dextran produced by the enzymatic reaction in a laminar flow was determined quantitatively.

We report for the first time that the sensitivity of the luminol-hypochlorite chemiluminescence (CL) reaction was enhanced approximately 10 times by the addition of phloxine B. The maximum wavelength of CL emission shifted from 431 to 595 nm in the absence and presence, respectively, of phloxine B, suggesting that an efficient chemiluminescence resonance energy transfer occurred between a luminol donor and a phloxine B acceptor in the luminol-hypochlorite-phloxine B system. Based on this observation, a simple, rapid and sensitive microflow injection CL method, using a microchip with spiral channel configurations, was developed for the determination of hypochlorite. Under optimized conditions, a linear calibration curve (R(2) = 0.9944) over the range 0.1-10.0 µmol/L was obtained, with a detection limit of 0.025 µmol/L (S:N = 3). The relative standard deviation (RSD) was found to be 4.2% (n = 10) for 2.5 µmol/L hypochlorite. The sample consumption was only 2 μL, with a sample throughput of 90/h. The method has been used for determining trace amounts of hypochlorite in water samples with satisfactory results.

Phenotypic switching is characterized as a virulence factor of Candida spp. This study was carried out to evaluate the phenotypic switching ability of C. krusei ATCC 14243 and to determine its effect on the biological properties, adherence capacity and susceptibility towards chlorhexidine digluconate (CHX). To induce switched generations C. krusei was cultured under nitrogen-depleted growth conditions by adding phloxine B. These phenotypically switched colonies were designated as the 1st generation. Subsequent sub-culturing was performed to produce the 2nd, 3rd and 4th switched generations. The recovery of the 3rd generation was the highest at 85.7% while that of the 4th generation was lower at 70.8%, and the recovery of the 1st and 2nd generations gradually reduced to 46.6% and 36.4%, respectively. All generations of C. krusei were susceptible towards CHX. The unswitched C. krusei was the most susceptible but the least adherent to coated hard surfaces. The 2nd generation was the least susceptible, but with the highest adherent ability. The minimum inhibition concentration and minimal fungicidal concentration of C. krusei of all generations were determined at 0.4 mg mL(-1) . These observations suggest that the switching activity of C. krusei induces changes to its biological properties and susceptibility towards CHX.

Poly(butadiene)-b-poly(ethylene oxide) vesicles were successfully loaded with hydrophilic dye Phloxine B. Dye addition during vesicle formation leads to Phloxine B encapsulated inside the water filled vesicle core as well as to freely diffusing dye molecules. The removal of uncapsulated substrate involves time consuming methods like dialysis or harsher methods like ultra filtration or selective precipitation, posing the risk of irreversible sample manipulation. Here used Phloxine B as pH sensitive fluorescence indicator allows the characterization of hydrophilic loading without separation procedure by adjusting the pH value. Additionally membrane blocking efficiency can be studied by time dependent fluorescence measurements. Cryogenic TEM studies showed that the self-assembled structure remained unchanged when the hydrophilic dye was incorporated within the vesicles. Fluorescence microscopy imaging proved the encapsulation of the hydrophilic dye inside the core volume. The combination of fluorescence correlation spectroscopy (FCS) and dynamic light scattering (DLS) measurements as ensemble methods confirmed those results additionally.

It was found that three kinds of the synthetic food additive dyes, red nr. 3 (erythrosine), nr. 104 (phloxine), and nr. 105 (rose bengal) were adsorbed to the surface of charred cellulose granules and the maximum amounts of adsorption of these dyes were 3.75, 3.42, and 4.74 mg/g cellulose, respectively. Scanning electron microscopy-electron probe micro analysis (SEM-EPMA) showed a coating of the dyes on the surface of charred cellulose granules. Electron spectroscopy for chemical analysis (ESCA) suggested the presence of NH3 + in the surface of charred cellulose granules. Since all three dye compounds have both anionic carboxylate and hydrophobic groups and were released from the surface of charred cellulose granules by 0.1 N NaOH solution, it was surmised that these three food additive dyes were bound to the surface of cellulose granules by both ionic and physical interactions.

A procedure for the automatic photometric determination of phosphate ions in natural waters was developed, based on the formation of a colored ion associate of the reduced form of phosphomolybdic heteropoly anion with a polymethine dye, Astra Phloxine. The detection limit was 5 μg P/L at the sample volume of 0.3 mL.

The synthetic food dyes studied were rose bengal (RB), phroxine (PL), amaranth, erythrosine B (ET), allura red, new coccine, acid red (AR), tartrazine, sunset yellow FCF, brilliant blue FCF, and indigo carmine. First, data confirmed that these dyes were not substrates for CYP2A6, UGT1A6, and UGT2B7. ET inhibited UGT1A6 (glucuronidation of p-nitrophenol) and UGT2B7 (glucuronidation of androsterone). We showed the inhibitory effect of xanthene dye on human UGT1A6 activity. Basic ET, PL, and RB in those food dyes strongly inhibited UGT1A6 activity, withIC50values = 0.05, 0.04, and 0.015 mM, respectively. Meanwhile, AR of an acidic xanthene food dye showed no inhibition. Next, we studied the inhibition of CYP3A4 of a major phase I drug-metabolizing enzyme and P-glycoprotein of a major transporter by synthetic food dyes. Human CYP3A4 and P-glycoprotein were also inhibited by basic xanthene food dyes. TheIC50values of these dyes to inhibit CYP3A4 and P-glycoprotein were the same as the inhibition level of UGT1A6 by three halogenated xanthene food dyes (ET, PL, and RB) described above, except AR, like the results with UGT1A6 and UGT2B7. We also confirmed the noninhibition of CYP3A4 and P-gp by other synthetic food dyes. Part of this inhibition depended upon the reaction ofO12originating on xanthene dyes by light irradiation, because inhibition was prevented byO1 2quenchers. We studied the influence of superoxide dismutase and catalase on this inhibition by dyes and we found prevention of inhibition by superoxide dismutase but not catalase. This result suggests that superoxide anions, originating on dyes by light irradiation, must attack drug-metabolizing enzymes. It is possible that red cosmetics containing phloxine, erythrosine, or rose bengal react with proteins on skin under lighting and may lead to rough skin.

Variability among microorganisms in barotolerance has been demonstrated at genus, species, and strain levels. Identification of conditions and additives that enhance the efficacy of ultrahigh pressure (UHP) against important foodborne microorganisms is crucial for maximizing product safety and stability. Preliminary work indicated that FD&C Red No. 3 (Red 3), a xanthene derivative, was bactericidal and acted synergistically with UHP against Lactobacillus spp. The objective of this study was to determine the antimicrobial efficacy of Red 3 and other xanthene derivatives, alone and combined with UHP, against spoilage and pathogenic bacteria in citrate-phosphate buffer (pH 7.0). Xanthene derivatives tested were fluorescein, Eosin Y, Erythrosin B, Phloxine B, Red 3, and Rose Bengal. Halogenated xanthene derivatives (10 ppm) were effective at reducing Listeria monocytogenes survivors but ineffective against Escherichia coli O157:H7. When combined with UHP (400 MPa, 3 min), the presence of derivatives enhanced inactivation. Because Red 3 was the only xanthene derivative to produce synergistic inactivation of both pathogens, further studies using this colorant were warranted. Efficacy of Red 3 against gram-positive bacteria (Lactobacillus plantarum and L. monocytogenes) was concentration dependent (1 to 10 ppm). E. coi O157: H7 strains were resistant to Red 3 concentrations up to 300 ppm. When Red 3 was combined with UHP, the lethality against gram-positive and gram-negative bacteria was dose dependent, with synergy being significant for most strains at > or = 3 ppm. Additional gram-positive and gram-negative bacteria showed lethalities similar to those observed for L. plantarum or L. monocytogenes, and E. coli O157:H7, respectively. Red 3 is a potentially useful additive to enhance the safety and stability of UHP-treated food products.

This paper reviews the nature of Romanowsky staining and the relationship between Romanowsky dyes and the Romanowsky-Giemsa effect (RGE). On blood and bone marrow smears the RGE is characterized by a purple colouration of nuclei and neutrophil granules. The nuclear purple contrasts strongly with the blue cytoplasmic staining of cells rich in RNA. Requirement for the occurrence of RGE are: I A cationic dye: The best dye is azure B and, though azure A gives the nuclear purple colour, the cytoplasmic blue is inferior. No other cationic dye such as methylene blue is suitable. 2 An anionic dye: Most commonly eosin Y is used, but it can be replaced by the erythrosins. Full halogenation of the fluorescein (four atoms of bromine or iodine) is not necessary. Phloxine and rose bengal are unsuitable. 3 An appropriate substrate: These are proteins with acidic side groups or proteins bound to a polyanion. For the interaction with the dyes substrates must provide a suitable three-dimensional network which is why the RGE is not obtained in solutions. A tentative theory of RGE is advanced and briefly discussed.

The hyphal sheath is a morphological feature of many kinds of fungi. Although the fine structures of the sheath have been studied in detail by a number of electron microscopy techniques, the function and physiology of the hyphal sheath are not yet clarified. One reason for this is that the hyphal sheath is a colorless, mucilaginous, and delicate material so that it is not easily identified. We developed a simple method to visualize and identify the hyphal sheath of the white-rot fungus Phanerochaete crassa WD1694. The small mycelial pellets in shaken liquid cultures of P. crassa WD1694 were stained directly with phloxine B. Both the hyphae and the hyphal sheath that filled the gaps between each of the hyphae were visualized and observed by light microscopy. The stained hyphae were further studied by transmission electron microscopy, atomic force microscopy, and fl uorescence microscopy. Based on these observations, we confirmed that the staining of the hyphae was also due to the presence of the hyphal sheath that closely covered the fungal cell wall. These results clearly showed that the hyphal sheath was selectively stained with phloxine B and could be observed and identified by conventional light microscopy.

Intermolecular interactions between the fluorescent organic dyes Fluorescein, Fluorescein Diiodide, Eosin, Rose Bengal, Erythrosin, Phloxine, Phloxine B, Rhodamine 6G, Lissamine Rhodamine B200 and the non fluorescent Crystal Violet and Malachite Green in aqueous solution have been studied by fluorescence quenching and difference absorption spectrophotometry. Equilibrium constants for the interactions have been determined by the two techniques mentioned and are compared. Absorption and fluorescence spectra and rates of photolysis of solutions obtained by extracting aqueous solutions of the mixed dyes into organic solvents are described.

A highly sensitive and selective reaction of 12-molybdophosphate with the polymethine dye Astra Phloxine has been used for the spectrophotometric determination of phosphate. If the concentration of phosphate is less than 1 µmol L−1, supersaturated solutions of ion associate (IA) are stable without the use of a surfactant. Under these conditions, a new band appears in the absorption spectrum at 574 nm. The color of the IA develops immediately after mixing of reagents and remains constant over several hours. The molar absorptivity of the IA is 1.54 × 105 L mol−1 cm−1. The calibration graph is linear between 0.02 and 0.8 µmol L−1 of phosphate. The limit of detection is 7 nmol L−1. Phosphate was determined in pure chemicals and water samples, including Dead Sea water.

We have reported that erythrosine (ET), a xanthene dye, inhibited uridine 5-diphosphate (UDP)glucuronosyltransferase 1A6 (UGT1A6). In order to clarify the structure-inhibition relationships of these xanthene dyes, the inhibitory effect of xanthene dye on human UGT1A6 activity was investigated, such as acid red (AR), ET, phloxine (PL), and rose bengal (RB). ET, PL, and RB strongly inhibited human UGT1A6 activity, with IC50 values = 0.05, 0.04, and 0.015 mM, respectively. Meanwhile, AR had almost no effect (IC50 value = 1.7 mM). ET, PL and RB have four halogen atoms on their xanthene backbone, unlike AR. Meanwhile, some contrast media with high halogens on those aromatic compounds, such as ioxaglic acid, iodixanol, meglumine iotalamate, and diatriazole sodium, did not inhibit human UGT1A6 activity. These results suggest that halogens enhance the inhibitory effect of xanthene dyes. In this study, it was proved that xanthene dyes had an inhibitory effect on human UGT1A6 activity by the combination of xanthene structure and halogens on its. Part of this inhibition by xanthene dyes depends the reaction of 1 O2 originated on xanthene dyes by light irradiation, because the inhibition was prevented by 1 O2 quenchers, such as NaN3 and histidine, and in the dark.

Phloxine B (DC red no. 28) is a color additive for food, drugs, and cosmetics. It has been previously shown to have anti-Staphylococcus aureus activities. In this work, the effect of Phloxine B on various gram-negative bacteria and other gram-positive bacteria including Bacillus cereus, Bacillus thuringiensis, Bacillus mycoides, Bacillus subtilis, Bacillus aureus, Salmonella, Escherichia coli and Shigella was studied, along with the mechanism of anti-microbial activity. In the presence of fluorescent light, the viable count for gram-positive bacteria, (Bacillus spp. and S. aureus) decreased in a dose and time dependent manner when incubated with Phloxine B. The viability of gram-positive bacteria was reduced by 99.99% in 40 min, while there was no effect on gram-negative bacteria (Salmonella choleraesuis, E. coli and Shigella flexneri). However, the use of ethylenediaminetetraacetic acid (EDTA) expands the spectrum of activity for Phloxine B to include gram-negative bacteria. EDTA increased membrane-permeability by releasing lipopolysaccharide. Overall, in an Agar diffusion test the light-dependent bactericidal activity of 1 microg of Phloxine B had a potency of 0.64 units of chloramphenicol and 0.5 units of tetracycline when tested on B. cereus, and had a potency of 0.7 units of chloramphenicol and 0.2 units of tetracycline when tested on S. aureus. The data suggest that the dye may have some potential anti-microbial applications.

Ferric species were immobilized on different types of ionic exchange resins, and used as a heterogeneous catalyst for degradation of cationic and anionic dye pollutants under visible light ( λ > 450 nm) irradiation in the presence of H 2 O 2 . It was found that for the photodegradation of cationic dyes, malachite green and methylene blue, the immobilized catalyst on a strongly or weakly cationic resin was much more effective than the catalyst supported on an anionic resin, whereas an opposite order in the catalyst activity was observed for the photodegradation of anionic dyes, phloxine and X3B. This significant difference was mainly attributed to the dye adsorption, which enhanced the electron transfer from the excited dye to the immobilized ferric species. All the catalysts were stable upon visible light irradiation, and less than 3.2 μM of dissolved Fe species was detectable in the filtrate solution. When the ferric species was loaded on an amphoteric exchange resin, the immobilized catalyst was effective to the photodegradation of both cationic and anionic dyes. The anionic dyes were notably adsorbed on such the catalyst, but the catalyst exhibited weak affinity toward cationic dyes. Due to the inner salt effect, some dissolved ferric species was released from the solid, and consequently made some contribution to the overall dye degradation via both the Fenton reaction and the photosensitization pathway. Although the amphoteric resin-supported catalyst was stable to the visible light, it was corroded to a certain level upon UV irradiation. It was found that such photodissolution was greatly depressed in the presence of H 2 O 2 .

There is a fluorescence peak at 570 nm, and a maximum absorption peak at 560 nm for phloxine (PHLO) in a pH 7 water solution. Under these conditions, the ciprofloxacin cation (CPFX+) and PHLO- combine into hydrophobic CPFX-PHLO association molecule by means of static gravitation. There are stronger van der Waals forces and hydrophobic forces among the CPFX-PHLO molecules. Thus, they aggregate automatically to the (CPFX-PHLO)n association nanoparticle in red-violet color. That was characterized by scan electron microscopy (SEM), hyperfiltration and dialysis tests. In 0.04 M HCl, the red-violet nanoparticles exhibited a Rayleigh scattering peak at 470 nm, a resonance scattering peak at 580 nm, a maximum absorption wavelength at 565 nm, and a fluorescence peak at 450 nm. The fluorescence analytical conditions of CPFX have been considered. The CPFX concentration in the range of 1.0 x 10(-6)-4.0 x 10(-5) M is linear to the fluorescence intensity, F450nm. The detection limit was achieved at 4.0 x 10(-7) M CPFX. The CPFX in real samples was determined with satisfactory results.

D&C Red No. 28 (Red 28) is a US certified color additive used in drugs and cosmetics. Little is known about the extent of systemic absorption and pharmacokinetic behavior of Red 28. Therefore, these studies were performed to determine oral bioavailability and pharmacokinetic parameters of Red 28 in male F-344 rats following single and repeated oral dosing. Rats were administered either a single i.v. dose (50 mg/kg), a low oral gavage dose (50 mg/kg), or a high oral gavage dose (500 mg/kg) of Red 28. Plasma, urine and feces samples were subjected to solid phase extraction (SPE) and analyzed by HPLC for Red 28. Regardless of the dose or route of administration, the terminal t1/2 of Red 28 was 2.5 h. The major route of elimination was fecal excretion, with 88% (i.v.) and 98% (50 mg/kg p.o.) of the dose recovered by 96 h. Urinary excretion of Red 28 accounted for 1% of the dose following i.v. administration. No Red 28 was detected in urine after p.o. administration. Biliary excretion was determined experimentally to be the primary route of elimination for systemically available Red 28. Bioavailability following p.o. administration was very low (1–2%) and was not altered significantly by 14 days of dietary pretreatment with Red 28. # 2003 Elsevier Ltd. All rights reserved.

A method for the determination of 12 synthetic food dyes (Amaranth, Erythrosine, Allura Red AC, New Coccine, Phloxine, Rose Bengal, Acid Red, Tartrazine, Sunset Yellow FCF, Fast Green FCF, Brilliant Blue FCF, Indigo Carmine) in food was developed using capillary electrophoresis (CE) with photodiode array detection. The dyes were extracted with water and 0.5% ammonia-ethanol (1:1) mixture, and cleaned up using solid-phase extraction (Sep-Pak Plus tC18). The dyes were eluted with methanol from the cartridge. The dyes were separated by CE on a bubble cell fused-silica capillary (72 cm to the detector, 75 microm i.d.) using 20% acetonitrile in a mixture of 10 mmol/L potassium phosphate, monobasic and 5 mmol/L sodium carbonate (pH 10.0) as the running buffer. Identifications of the dyes were performed on the basis of the migration time and the absorbance spectrum of each peak. The coefficients of variation of the migration times and the peak areas were 0.28-0.62% and 1.84-4.30%, respectively (n = 5). The identification limits using the absorbance spectra of the dyes were 10 microg/mL for Brilliant Blue FCF and Fast Green FCF, and 5 microg/mL for the other 10 dyes. The recoveries of the 12 dyes from pickles, soft drinks and candies at the level of 10 microg/g were 70.0-101.5%. The method was applied to the analysis of dyes in foods. The dyes detected by CE were in agreement with those detected by paper chromatography.

Studies were conducted to determine attraction and feeding propensity of Mediterranean fruit fly, Ceratitis capitata (Wiedemann), to different protein bait mixtures with and without the insecticides malathion, spinosad, and phloxine B. Protein baits were more attractive to females than to males. Protein-starved females responded more than protein-fed females. The type of protein (USB yeast hydrolysate enzymatic, MazofermE802, Nu-LureInsect Bait, or Provesta 621 autolyzed yeast extract) in the bait had a major influence on C. capitata attraction, which was strongest to fresh Provesta. Aged baits (four day-old) were not as attractive as fresh baits. In feeding propensity studies, highest response was observed for USB protein. On the basis of attraction and feeding responses Provesta (attraction and feeding) and USB (feeding) outperformed the standard Nu-Lure. Protein-starved flies were much more likely to feed on protein compared to protein-fed flies. For protein-starved flies, a mixture of Provesta and malathion repelled fruit flies, compared to a mixture of Provesta and spinosad or phloxine B. This was not the case with protein–fed flies. The wasp Fopius arisanus (Sonan), one of C. capitata’s primary natural enemies in Hawaii, would not consume protein baits. Our studies suggest that spinosad or phloxine B, with low contact toxicity, mixed with protein baits offers a more environmentally friendly choice for control of C. capitata and conservation of F. arisanus, whereby the nontarget effects of broad spectrum contact poisons such as malathion can be avoided. Presumably, due to greater selectivity with spinosad and phloxine B bait treatments, the host would be killed, but not the natural enemy.

In order to choose the best insecticide for fruit fly protein hydrolysate baits in field,laboratory tests were taken to assess the stomach toxicity of spinosad and phloxine B with torula yeast protein hydrolysate on oriental fruit flies,Bactrocera dorsalis (Hendel) female and male adults.Median lethal concentration values of spinosad and phloxine B on B.dorsalis male and female adults at 5 h were 12.757 0 mg/kg,13.953 5 mg/kg;779.937 8 mg/kg,826.625 9 mg/kg respectively.Median lethal time of spinosad was 4.190 4 h(females) and 4.973 0 h(males) at 16 mg/kg and 100 mg/kg;The median lethal time of spinosad was 2.487 7 h(females) and 2.675 5 h(males).For phloxine B,at 630 mg/kg the median lethal time was 5.350 7 h(females) and 4.946 2 h(males),and at 1,000 mg/kg the median lethal time was 4.765 0 h(females) and 4.571 5 h(males).

The field efficacy of a bait containing phloxine B, uranine and Provesta 621 protein was tested against Mediterranean fruit fly (Ceratitis capitata; Medfly) by aerial and ground spraying in about 84 ha of coffee fields in Kauai, Hawaii, USA. Concurrently, soil and crop samples were collected from the aerially sprayed field and its unsprayed control field for residue studies. Efficacy of the sprays was assessed through trapping with both protein-baited and trimedlure-baited traps and through the infestation level of coffee cherries collected at least three-quarters ripe. The C capitata population was low at the start of the aerial and ground spray studies, but dramatically increased in the control fields. This increase coincided with initial ripening of coffee cherries. During times of peak population levels, C capitata populations were reduced by more than 91% in the ground-sprayed field and 99% in the aerial-sprayed field, relative to the populations in their respective control fields and based on protein-baited trap catches. Results of residue analyses indicated that uranine dissipated quickly compared with phloxine B on coffee and soil. Coffee samples collected at pre-spray periods had phloxine B residues of 7.2–25.5 ng g−1 on berries. Phloxine B concentrations were much higher on coffee leaves (163–1120 ng g−1). Lower concentrations of the dye were found from coffee samples collected during rainy days. Average phloxine B concentrations immediately after spraying were 56 and 2840 ng g−1 in coffee berries and leaves, respectively. Dissipation of phloxine B on berries was fast, with a half-life (t1/2) of 3 days. Dissipation of phloxine B on leaves was fitted to two linear phases: the initial (0–4 days) with a shorter t1/2 of 3 days and the later phase (4–28 days) with a longer t1/2 of 15 days. Average concentrations of phloxine B in the top soil ranged from 50 to 590 ng g−1 at pre-spray. Phloxine B initial concentration (770 ng g−1) reached a plateau immediately after the last spraying, but showed a steady decline over time with t1/2 of 16 days. Fast dissipation of the dyes in the field indicates that these chemicals may be environmentally compatible and therefore a promising alternative for fruit fly control. © 2001 Society of Chemical Industry

The effects of the fluoresceine derivative, phloxine B, on the Cl− current through the cystic fibrosis transmembrane conductance regulator (CFTR) were examined in Xenopus oocytes expressing human CFTR. In whole oocytes, the CFTR Cl− current (ICFTR) was activated by superfusion with isobutylmethylxanthine and forskolin. ICFTR was stable during activation and deactivated rapidly upon washout of the activation solution. Phloxine B slowed deactivation and, at high concentrations, inhibited ICFTR weakly. In excised inside-out macropatches, ICFTR was activated by the catalytic subunit of protein kinase A (cPKA) and MgATP. Phloxine B (0.01–3 μM), applied after activation, increased ICFTR within 30 s followed by a slow decrease which became dominant at high concentrations. Slowing of deactivation of the CFTR was observed at all concentrations. The effect of phloxine B after 30 s had a bell-shaped concentration-dependence with midpoints at 45 and 1600 nM for the stimulatory and the inhibitory limb, respectively; maximum stimulation was about 1.8 times. The slow inhibitory component, measured after 6 min, occurred with an IC50 value of ∼1 μM. In the absence of cPKA, phloxine B did not stimulate ICFTR. In the presence of cPKA and MgATP, the effects of phloxine B were more prominent at low (0.02 mM) than at high ATP (2 mM). The data show that phloxine B modulates ICFTR by increasing channel activity and slowing channel deactivation; at high concentrations inhibition dominates. The effects may be mediated by direct interactions with CFTR from the inside of the cell. British Journal of Pharmacology (2000) 131, 433–440; doi:10.1038/sj.bjp.0703600

Many photoactive dyes are relatively nontoxic to vertebrates despite their insecticidal properties. Several photoactive dyes known to be toxic to some groups of insects were evaluated at various concentrations for toxicity to American and migratory grasshoppers in laboratory and field studies. Rose bengal and phloxine B were effective at inducing mortality of grasshoppers when applied at 2 and 5% to bran bait, though erythrosin B and uranine were ineffective. Partial replacement of phloxine with uranine in dye mixtures resulted in no significant loss of efficacy. Some indication of feeding inhibition was observed at high dye concentrations, so minimum effective dosages, probably 2%, are optimal. Phloxine B and rose bengal appeared to be stable upon exposure to sunlight, and able to withstand at least 24 h of sunlight without significant degradation. Dyes such as phloxine B could be a viable grasshopper control agent for small or medium-sized grasshopper species because mortality can be induced by consumption of a single flake dusted with 5% dye, and yet pose little hazard to vertebrates. Large species such as American grasshopper must consume several flakes before mortality is induced.

Agrobacterium tumefaciens cells were killed upon illumination when treated with submicromolar concentrations of phloxine B. Phloxine B could be distributed systemically through a plant by amending the water supply or delivered directly to specific locations through topical applications in 0.1% adjuvant (Kinetic HV). Sweet basil (Ocimum basilicum L.), jimsonweed (Datura stramonium L.), and soybean (Glycine max L.) were infected with A. tumefaciens to establish a marker for a systemic pathogenic bacteria. There was a >90% reduction in the plants' population of A. tumefaciens when watered daily with a 1 micromolar phloxine B solution. Furthermore, the plants treated with phloxine B were asymptomatic to the pathogenic challenge. Leaf tissue, collected from basil and soybean, also expressed a reduction in the population of A. tumefaciens by >90% when treated under greenhouse conditions for 24 h with 10 μM phloxine B in 0.1% Kinetic HV. The possible use of phloxine B as an agent to control bacterial diseases in plants is suggested.

A method was developed for the analysis of phloxine B and uranine, photoactive dyes being evaluated as fruit fly toxicants, in coffee cherries and green and roasted beans. The analytes were measure...

A simple and rapid on-line analytical system was configured for the evaluation of the photostability of various food coloring agents constantly exposed to light. The screening test for photostability of food coloring agents was carried out in the system consisting of 60 cm of Teflon tubing for ultraviolet (UV) irradiation with a flow rate of mobile phase (water/acetonitrile = 1:1, v/v) at 1 mL/min. When the products derived from photochemical reaction of phloxine (R-104), which is recognized to exhibit chemiluminescence induced by UV irradiation, were separated, several peaks were confirmed on the chromatogram in this system. Furthermore, the peak of chemilumigenics observed on the chromatogram of photon-counting chemiluminescence detection corresponds to the new peaks on the UV chromatogram. Also, the presence of phenoxy radical (g = 2.0061) formed by UV irradiation of R-104 was confirmed with an electron spin resonance spectrometer, indicating a reasonable relationship (r = 0.9041) between the formation...