DOCSLIB.ORG

Food, Drug, and Cosmetic Dyes: Biological Effects Related to Lipid

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Food, Drug, and Cosmetic Dyes: Biological Effects Related to Lipid Proc. Natl. Acad. Sd. USA Vol. 74, No. 7, pp. 2914-2918, July 1977 Cell Biology Food, drug, and cosmetic dyes: Biological effects related to lipid solubility (molluscan neurons/toxicity/uncouplers/anticoagulants/brain uptake) HERBERT LEVITAN Department of Zoology, University of Maryland, College Park, Maryland 20742 Communicated by Harry Grundfest, April 29,1977 ABSTRACT Food, drug, and cosmetic dyes of the xanthane system was used previously to provide insights into the cellular type (analogs of fluorescein) were applied to isolated molluscan mechanism of action of nonnarcotic analgesics in vertebrates ganglia and changes in the electrophysiological properties of (10, 11) and it was hoped it might serve a similar function for identified neurons were monitored. The synthetic coloring agents increased the resting membrane potential and conduc- the current problem. The ganglion was isolated from the ani- tance of the neurons in a dose-dependent manner by increasing mal, pinned to Sylgard (Dow Corning, Midland, MI) in the the potassium permeability of the membrane relative to that bottom of a small plastic dish (5 ml) and usually bathed in a of other ions. The relative activity of these anionic dyes was low-potassium physiological saline consisting of 500 mM NaCl, highly correlated with their lipid solubility. The structure-ac- 1 mM KCI, 10 mM CaC12, 50 mM MgCl2, and 10 mM Tris-HCl tivity study of the effects of the dyes on molluscan neuro- at pH 7.8. The potassium concentration was increased by iso- physiology provides a basis for estimating the toxicity and brain tonic substitution for sodium. The capsule enveloping the uptake of the dyes in vertebrates, and predicting their effects ganglion was cut, exposing large, previously identified neurons on metabolism and blood clotting. (12). These neurons were impaled with double-barreled mi- Synthetic dyes have been a constituent of foods, drugs, and cropipettes with tip diameters of 2 Asm or less, and filled with cosmetics for more than 100 years, and the safety of such ad- 3 M KC1. The neuronal membrane potential was monitored ditives has been of concern for almost as long (1). The intended with one barrel using standard electrophysiological technique function of these additives has been to enhance the physical (12). The second barrel was connected to a source of constant appearance of a product, and some proof of their safety, which current pulses so that total membrane conductance could be has in the past been either assumed or ignored, is now required monitored. in many countries before they can be incorporated into items The compounds selected for testing belong to the xanthene intended for human consumption (1-5). Despite such precau- group of dyes and are derivatives of fluorescein (Table 1). tions several coloring agents were used for decades before they Fluorescein itself is frequently used in angiography to visualize were ruled unsafe, and the use of other dyes is currently under the blood vessels of the eye (17) and some of its derivatives are review because deleterious effects have been discovered or are used to color foods and drugs (4). The dye to be tested in the suspected (1, 5). Interest in the biological activity of artificial current system was dissolved in the physiological saline just prior colorants has recently been renewed following the claims that to use, and was applied to the impaled neurons by exchanging a red food dye (FD&C Red No. 2) is carcinogenic (6) and that the normal physiological medium for one containing the some food additives, and colorants in particular, may be re- dye. sponsible for producing behavioral changes and learning disabilities in children (e.g., hyperkinesis, minimal brain dis- RESULTS function) (7-9). The application of the fluorescein dyes to the molluscan ganglia The present study was undertaken in order to determine (i) produced a rapid increase in the membrane potential and whether some types of synthetic dyes, which are added to foods conductance of the impaled neuron (Fig. 1). The amplitude of and drugs purely for cosmetic purposes, are in fact biologically the response to a particular dye was variable and dependent active compounds, and (ii) the physicochemical properties of upon several factors, including the identity of the neuron im- the compounds responsible for their activity. It was found that paled, the animal, the time of year the experiment was per- xanthane type dyes alter the physiological characteristics of formed, and the number of previous exposures to that dye or invertebrate neurons and that their biological activity is highly others. Because of desensitization in the response to repeated correlated with the compounds' lipid solubility. The struc- dye applications and/or a slow irreversible decline in the ture-activity study of the dyes' effects on neurons provided a membrane potential produced by some of the dyes, complete basis for estimating their toxicity and brain uptake in verte- dose-response curves were rarely obtained. In order to have a brates, and predicting their effects on metabolism and blood common base with which to compare the relative effectiveness clotting. of the several dyes, the response of a neuron to each dye was compared with its response to a preceding and subsequent METHODS AND MATERIALS application of 12 mM salicylate, an organic anion of related in Experiments were performed primarily on the buccal ganglia structure known to produce similar effects this system of the marine mollusc Navanax inermis (obtained from Pacific (18-21). This concentration of salicylate produces half the Biomarine Supply Co., Venice, CA). This invertebrate nervous maximum change in membrane potential and conductance and its effects are reversible. The concentration of a particular dye Abbreviations: FD&C denotes approval by the United States Food and that produced an increase in membrane potential equal to that Drug Administration for use in food, drugs, and cosmetics; D&C, ap- produced by 12 mM salicylate was considered the concentration proved for drugs and cosmetics. that would produce half the maximum change in membrane 2914 Downloaded by guest on September 29, 2021 CdYBiology:BgUvitin Proc. Nati. Acad. Sci. USA 74 (1977) 2915 Table 1. Biological activity and partition coefficient of fluorescein analogs R2 NaOm Ri1 cOONa Predicted values Colour Index R <Rl Cso, mM LD5,i (1971) R, Ob- Pre- I50,g F,h mmol/ BUI, Compounda no.b R1 R2 R3 R4 R5 log Pc servede dictedf mM mM kg % 1. Fluorescein (D&C Yellow No. 8) 45350 H H H H H -4.77 200 300 50* 3200* >10* * 2. D&C Orange No. 9 45365 H Cl H Cl H -3.77 38 11* 1000* >10* 2 3. Eosin 2J (D&C Orange No. 6) 45370 H Br H Br H -3.02 22 4 400* >10* 4 4. Erythrosin Y (D&C Orange No. 11) 45425 H I H I' H -2.46 10 2 200* >10* 10 5. Eosin B 45400 H Br NO2 Br NO2 -2.18d 8 6 1 135* >10* 14 6. D&C Red No. 25 45366 H Cl Cl Cl Cl -1.97 - 5 0.9 105* >10* 19 7. Eosin Y (D&C Red No. 23) 45380 H Br Br Br Br -1.27 4 2 0.3 47 >10* 40 8. Erythrosin B (FD&C Red No. 3) 45430 H I II I -0.15d 0.2 0.3 0.06 10 8 82 9. Ext. D&C Red No.5 45435 di-Cl I I I I 1.44 0.03 0.006 2 2 86* 10. Phloxine B (D&C Red No. 28) 45410 . Cl Br Br Br Br 2.02 0.01 0.01 0.003* 1 1 65* 11. Rose Bengal 45440 Cl I I I I 3.14 0.002 0.0005* 0.2* 0.6 25* a FD&C denotes approval by the United States Food and Drug Administration for use in foods, drugs, and cosmetics; D&C, drugs and cosmetics; Ext., external. Fluorescein, Eosin B, Eosin Y, Phloxine B, and Rose Bengal are certified dyes obtained from Matheson, Coleman, and Bell, Norwood, OH; Erythrosin B was a gift from M. Chin, Stange, Co., Chicago IL. b The Colour Index number provides unique identification of the compounds (4). C With the exception of compounds 5 and 8, the octanol/water partition coefficients, P, of the ionized form of the molecules were calculated by applying the additive-constitutive rules established by Hansch et al. (13). d Octanol/water partition coefficients of ionized form of these molecules determined experimentally by Bio- and Pharmaceutical Analysis Section, Midwest Research Institute, Kansas City, MO. Sodium was the co-ion in all cases. The pKa values of Eosin and Errthrosin B were found to be 4.95 and 5.04, respectively. e C5o = concentration, estimated from experimental observations, that would produce halfthe maximal increase in membrane potential ofidentified molluscan neurons. f C50 predicted from least squares fit of data points (Eq. 1). g Iso = concentration that should inhibit oxidative phosphorylation ofisolated rat liver mitochondria by 50%, predicted from an equation describing similar activity of salicylate analogs (see text). 'h F = concentration that should dissolve a standard clot of human plasma in 24 hr, predicted from an equation describing similar activity of salicylate analogs (14). LD5o = concentration that should kill 50% ofthe mice that receive an intravenous administration, predicted from an equation describing similar activity of benzoate analogs (15). BUI = Brain uptake index or-ratio of concentration of organic anion to tritiated water which should be found in rat brain to that injected into the internal carotid artery 15 sec earlier (16). * The partition coefficient for these compounds lies outside the range of data from which the equation was originally calculated.
Load more

Recommended publications
  • Counterstaining Hemalum
    Counterstaining Hemalum Bryan D. Llewellyn A presentation to the Queensland Histology Group at Caloundra, Queensland, Australia, May 2008. Bryan Llewellyn – Counterstaining Hemalum –Caloundra, Queensland – May, 2008 Yesterday I spoke about alum hematoxylin staining The former are carboxyl, hydroxyl and sulphonic but I did not comment on the counterstain usually groups predominantly, while the latter are nearly used, i.e. eosin. As an acid dye, eosin staining has always amino groups. In most cases it involves plain much in common with other acid dyes, such as those ionic bonds. used for single solution and multi-step trichrome methods and the various quad stains. The basic underlying principles are very similar, merely the The Eosins application being different. Eosin belongs to a group of dyes called fluorones, which are derived from fluorescien(Horobin and Kiernan Acid dyes as a group are quite diverse, ranging from 2002.). The sodium salt of fluorescien is called uranin. picric acid, which has a molecular weight of 229, to It is not used histologically, but its relationship to the large molecular weight dyes such as fast green eosin is quite apparent when the formulae are FCF at 809. In fact, this difference in molecular compared. These dyes are fluorescien homologues weights is one of the features of these dyes that halogenated with bromine, iodine or chlorine. Eosin enables us to manipulate them so successfully. Y ws itself is tetrabromofluorescien, for instance, i.e. fluorescien with four bromine atoms attached. So what is an acid dye? Simply put, it is an organic salt in which the anion is intensely coloured, and The free anion of eosin Y is called eosinol Y, and its which will attach to cations while retaining its colour.
    [Show full text]
  • Physico-Chemical Characterization and Antimicrobial Properties of Hybrid Film Based on Saponite and Phloxine B
    molecules Article Physico-Chemical Characterization and Antimicrobial Properties of Hybrid Film Based on Saponite and Phloxine B Nitin Chandra teja Dadi 1, Matúš Dohál 1,†, Veronika Medvecká 2, Juraj Bujdák 3,4, Kamila Koˇci 1 , Anna Zahoranová 2 and Helena Bujdáková 1,* 1 Department of Microbiology and Virology, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; [email protected] (N.C.t.D.); [email protected] (M.D.); [email protected] (K.K.) 2 Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, 842 48 Bratislava, Slovakia; [email protected] (V.M.); [email protected] (A.Z.) 3 Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, 842 15 Bratislava, Slovakia; [email protected] 4 Institute of Inorganic Chemistry of SAS, 845 36 Bratislava, Slovakia * Correspondence: [email protected]; Tel.: +421-2-9014-9436 † Current address: Department of Pharmacology and Biomedical Center Martin, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, 036 01 Martin, Slovakia. Abstract: This research was aimed at the preparation of a hybrid film based on a layered silicate saponite (Sap) with the immobilized photosensitizer phloxine B (PhB). Sap was selected because of its high cation exchange capacity, ability to exfoliate into nanolayers, and to modify different surfaces. The X-ray diffraction of the films confirmed the intercalation of both the surfactant and PhB molecules in the Sap film. The photosensitizer retained its photoactivity in the hybrid films, as shown Citation: Dadi, N.C.t.; Dohál, M.; by fluorescence spectra measurements.
    [Show full text]
  • 2,4,5,7-Tetrabromo-6- Hydroxy-3-Oxo-3H-Xanthen-9-Yl)- (Solvent Red 48
    Screening Assessment for the Challenge Benzoic acid, 2,3,4,5-tetrachloro-6-(2,4,5,7-tetrabromo-6- hydroxy-3-oxo-3H-xanthen-9-yl)- (Solvent Red 48) Chemical Abstracts Service Registry Number 2134-15-8 Environment Canada Health Canada September 2010 Screening Assessment CAS RN 2134-15-8 Synopsis Pursuant to section 74 of the Canadian Environmental Protection Act, 1999 (CEPA 1999), the Ministers of the Environment and of Health have conducted a screening assessment on Benzoic acid, 2,3,4,5-tetrachloro-6-(2,4,5,7-tetrabromo-6-hydroxy-3-oxo- 3H-xanthen-9-yl)- (Solvent Red 48), Chemical Abstracts Service Registry Number 2134- 15-8. This substance was identified as a high priority for screening assessment and included in the Ministerial Challenge because it had been found to meet the ecological categorization criteria for persistence, bioaccumulation potential and inherent toxicity to non-human organisms and is believed to be in commerce in Canada. The substance Solvent Red 48 was not considered to be a high priority for assessment of potential risks to human health, based upon application of the simple exposure and hazard tools developed by Health Canada for categorization of substances on the Domestic Substances List. Therefore, this assessment focuses principally on information relevant to the evaluation of ecological risks. Solvent Red 48 is an organic substance that may be used as a dye in Canada in various applications including in personal-care products and in drugs. Based on the survey conducted under section 71 of CEPA 1999, no companies reported importing or manufacturing the substance above the reporting threshold of 100 kg/year, and no use of the substance was reported above the reporting threshold of 1000 kg/year in 2006.
    [Show full text]
  • An Optimized Staining Technique for the Detection of Gram Positive and Gram Negative Bacteria Within Tissue Sandra C
    Becerra et al. BMC Res Notes (2016) 9:216 DOI 10.1186/s13104-016-1902-0 BMC Research Notes TECHNICAL NOTE Open Access An optimized staining technique for the detection of Gram positive and Gram negative bacteria within tissue Sandra C. Becerra, Daniel C. Roy, Carlos J. Sanchez, Robert J. Christy and David M. Burmeister* Abstract Background: Bacterial infections are a common clinical problem in both acute and chronic wounds. With growing concerns over antibiotic resistance, treatment of bacterial infections should only occur after positive diagnosis. Cur- rently, diagnosis is delayed due to lengthy culturing methods which may also fail to identify the presence of bacteria. While newer costly bacterial identification methods are being explored, a simple and inexpensive diagnostic tool would aid in immediate and accurate treatments for bacterial infections. Histologically, hematoxylin and eosin (H&E) and Gram stains have been employed, but are far from optimal when analyzing tissue samples due to non-specific staining. The goal of the current study was to develop a modification of the Gram stain that enhances the contrast between bacteria and host tissue. Findings: A modified Gram stain was developed and tested as an alternative to Gram stain that improves the contrast between Gram positive bacteria, Gram negative bacteria and host tissue. Initially, clinically relevant strains of Pseudomonas aeruginosa and Staphylococcus aureus were visualized in vitro and in biopsies of infected, porcine burns using routine Gram stain, and immunohistochemistry techniques involving bacterial strain-specific fluorescent antibodies as validation tools. H&E and Gram stain of serial biopsy sections were then compared to a modification of the Gram stain incorporating a counterstain that highlights collagen found in tissue.
    [Show full text]
  • (JIPBS) Assessment of Bactericidal Activity of Some Essential
    e-ISSN: 2349-2759 p-ISSN: 2395- 1095 Journal of Innovations in Pharmaceutical and Biological Sciences (JIPBS) www.jipbs.com Research article Assessment of bactericidal activity of some essential oils from medicinal plants and selected food additives on Salmonella enteritidis, Staphylococcus aureus and Escherichia coli *1 2 Hend Abdulhameed Hamedo , Asem Abdel mawgoud Mohamed 1 Botany Department, Faculty of Science, El Arish University, Egypt. 2 Chemistry of Natural and Microbial Products Dept., Pharmaceutical Industries Div., NRC, Egypt. Key words: Bactericidal effect, medicinal Abstract plants, essential oils, food additives. The aim of the present study was to investigate and compare between the antibacterial *Corresponding Author: Hend properties of some essential oils derived from some medicinal plants and food additives against Abdulhameed Hamedo, Botany food borne pathogens Salmonella enteritidis, Staphylococcus aureus and E. coli. The Department, Faculty of Science, El Arish antimicrobial potential was determined performing the disc diffusion assay and also minimal inhibitory (MIC) and bactericidal (MBC) concentrations. The inhibitory ability manifested by University, Egypt. the essential oils and food additives against the bacterial strains varied significantly depending fundamentally on concentration, but also on bacterial species. Essential oils were the most bactericidal agents against the tested bacteria. The MIC and MBC values between 0.125 and 1.0 μg/ml for the most active essential oil of Thymus vulgaris followed by Salvia officinalis and Achillea santolina which had MIC and MBC against the tested bacteria ranged from 0.5- 4.0μg/ml and 1.5-6.0μg/ml for MIC and MBC respectively. The most active food additives against the tested bacteria were acetic acid and tartrazine while nisin and phloxine B had no effect on gram negative bacteria.
    [Show full text]
  • Food Compounds Inhibit Staphylococcus Aureus Bacteria and the Toxicity of Staphylococcus Enterotoxin a (SEA) Associated with Atopic Dermatitis
    22 Food Compounds Inhibit Staphylococcus Aureus Bacteria and the Toxicity of Staphylococcus Enterotoxin A (SEA) Associated with Atopic Dermatitis Reuven Rasooly and Mendel Friedman Western Regional Research Center, Agricultural Research Service, United States Department of Agriculture, Albany, California USA 1. Introduction Enterotoxigenic S. aureus is a major bacterial pathogen that develops multi-drug resistance to antibiotics (Pereira et al., 2009; Pu et al., 2011; Rhee & Woo, 2010). The enterotoxigenic bacteria and secreted toxins have been reported to cause clinical infections, and it has also been reported that they contaminate a broad variety of foods, including breaded chicken products (Pepe et al., 2006), canned mushrooms (Anderson et al., 1996), cheeses (Ertas et al., 2010; Ostyn et al., 2010; Rosengren et al., 2010), raw milk (Fusco et al., 2011; Heidinger et al., 2009), pork meat (Wallin-Carlquist et al., 2010), and other foods (Balaban & Rasooly, 2000) as well contaminating handles of shopping carts (Mizumachi et al., 2011) causing many foodborne illnesses in the United States each year (Shinefield & Ruff, 2009). Staphylococcal food poisoning is due to the absorption from the digestive tract into the circulation of the enterotoxins preformed in food A toxin level of <1 µg may induce symptoms of food poisoning. This level is reached with a bacterial population of >105 CFU/g food (Stewart, 2005). S. aureus produces the virulent staphylococcal enterotoxin A (SEA), a single chain protein that consists of 233 amino acid residues with a molecular weight of 27,078 Da. It has been estimated that staphylococcal enterotoxin A (SEA) secreted by the bacteria is associated with 78% of staphylococcal outbreaks (Vernozy-Rozand et al., 2004).
    [Show full text]
  • D&C Red No. 27 [CASRN 13473-26-2]
    D&C Red No. 27 [CASRN 13473-26-2] D&C Red No. 28 [CASRN 18472-87-2] Prepared October 2000 D&C Red No. 27/D&C Red No. 28 10/00 SUMMARY D&C Red No. 27 and D&C Red No. 28 are fluorescein-based dyes that were approved in 1982 for use in drugs and cosmetics (except the eye area). Cosmetic retail products containing these dyes are primarily lipsticks and blushers. Dyes physically associated with non-aqueous aluminum or zirconium minerals (lakes) are used in lipsticks, blushers, make-up preparations, hair dyes and colors, rouges and face powders. The toxicological data reviewed by FDA prior to approval of D&C Red No. 27 and D&C Red No. 28 did not include studies of acute phototoxicity or chronic phototoxicity (i.e. photocarcinogenesis). Our current knowledge of the photochemistry and photobiology of D&C Red No. 27 and D&C Red No. 28 raises new concerns about the long-term safety of these colorants. D&C Red No. 28 is now known to be an extremely efficient photodynamic sensitizer whose photo-excitation results in the formation of free radicals and singlet oxygen. These highly reactive species attack cellular components such as lipids, proteins and nucleic acids. Investigators have shown that the genetic damage sensitized by D&C Red No. 28 is mutagenic in bacterial assays. In addition, in vitro studies using mammalian cells have shown that D&C Red No. 28 sensitizes photooxidation of guanine bases in cellular DNA (i.e. 8-oxo-7,8-dihydroguanine), a lesion known to be mutagenic.
    [Show full text]
  • 'Safe' Photoantimicrobials for Skin and Soft-Tissue Infections
    ’Safe’ photoantimicrobials for skin and soft-tissue infections Mark Wainwright To cite this version: Mark Wainwright. ’Safe’ photoantimicrobials for skin and soft-tissue infections. International Journal of Antimicrobial Agents, Elsevier, 2010, 36 (1), pp.14. 10.1016/j.ijantimicag.2010.03.002. hal- 00594503 HAL Id: hal-00594503 https://hal.archives-ouvertes.fr/hal-00594503 Submitted on 20 May 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Accepted Manuscript Title: ‘Safe’ photoantimicrobials for skin and soft-tissue infections Author: Mark Wainwright PII: S0924-8579(10)00117-2 DOI: doi:10.1016/j.ijantimicag.2010.03.002 Reference: ANTAGE 3275 To appear in: International Journal of Antimicrobial Agents Received date: 7-12-2009 Revised date: 10-2-2010 Accepted date: 3-3-2010 Please cite this article as: Wainwright M, ‘Safe’ photoantimicrobials for skin and soft-tissue infections, International Journal of Antimicrobial Agents (2008), doi:10.1016/j.ijantimicag.2010.03.002 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form.
    [Show full text]
  • The Science and Application of Hematoxylin and Eosin Staining Skip Brown, M.Div, HT (ASCP) Robert H
    The Science and Application of Hematoxylin and Eosin Staining Skip Brown, M.Div, HT (ASCP) Robert H. Lurie Comprehensive Cancer Center Northwestern University [email protected] Living up to Life Stains and Staining Systems Routine Staining (Hematoxylin & Eosin) Nuclear detail/definition - Hematoxylin Contrasting counterstain - Eosin The Hematoxylin and Eosin Stain • Long history of use – Mayer 1904 • Primary diagnostic technique in the histo- pathology laboratory. • Primary technique for the evaluation of morphology • Widely used – 2.5 to 3 million slides per day Introduction • The Hematoxylin and Eosin combination is the most common staining technique used in histology. • The diagnosis of most malignancies is based largely on this procedure. • Customer expectations or preferences are extremely subjective The Hematoxylin and Eosin Stain • A better understanding of the basic chemistry of the H and E stain will provide the attendee with: – A greater knowledge of how to optimize or modify the technique to achieve the results desired – A greater knowledge of how to solve staining issues. Introduction • There are a number of commercially available formulations for both hematoxylin and eosins • Customers preference for a specific formulation is based largely on desired staining characteristics. • Other factors may include ease of use and throughput. Some Basics of Dye Chemistry • Why do dyes stain specific elements of cell and tissues? • Dyes demonstrate an affinity for molecules within cells and tissues. • Affinity is the result of
    [Show full text]
  • Phloxine B As a Probe for Entrapment in Microcrystalline Cellulose
    Molecules 2012, 17, 1602-1616; doi:10.3390/molecules17021602 OPEN ACCESS molecules ISSN 1420-3049 www.mdpi.com/journal/molecules Article Phloxine B as a Probe for Entrapment in Microcrystalline Cellulose Paulo Duarte 1, Diana P. Ferreira 1, Isabel Ferreira Machado 1,2, Luís Filipe Vieira Ferreira 1,*, Hernan B. Rodríguez 3 and Enrique San Román 3,* 1 Centro de Química-Física Molecular, and IN-Institute of Nanoscience and Nanotechnology Complexo Interdisciplinar, Instituto Superior Técnico, Universidade Técnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; E-Mails: [email protected] (P.D.); [email protected] (D.P.F.); [email protected] (I.F.M.) 2 Escola Superior de Tecnologia e Gestão, Instituto Politécnico de Portalegre, Lugar da Abadessa, Apt 148, 7301-901, Portalegre, Portugal 3 INQUIMAE / DQIAyQF, Facultad de Ciencias Exactas y Naturales, UBA, Ciudad Universitaria, Pab. II, C1428EHA, Buenos Aires, Argentina; E-Mail: [email protected] * Authors to whom correspondence should be addressed; E-Mails: [email protected] (L.F.V.F.); [email protected] (E.S.R.); Tel.: +351-218419252 (L.F.V.F.); Fax: +351-218464455 (L.F.V.F.). Received: 11 November 2011; in revised form: 26 January 2012 / Accepted: 2 February 2012 / Published: 7 February 2012 Abstract: The photophysical behaviour of phloxine B adsorbed onto microcrystalline cellulose was evaluated by reflectance spectroscopy and laser induced time-resolved luminescence in the picosecond-nanosecond and microsecond-millisecond ranges. Analysis of the absorption spectral changes with concentration points to a small tendency of the dye to aggregate in the range of concentrations under study.
    [Show full text]
  • Photochemical & Photobiological Sciences
    Photochemical & Photobiological Sciences Accepted Manuscript This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. We will replace this Accepted Manuscript with the edited and formatted Advance Article as soon as it is available. You can find more information about Accepted Manuscripts in the Information for Authors. Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal’s standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains. www.rsc.org/pps Page 1 of 20 Photochemical & Photobiological Sciences Tuning the Concentration of Dye Loaded Polymer Films for Maximum Photosensitization Efficiency: Phloxine B Manuscript in Poly(2-Hydroxyethyl Methacrylate) Yair Litman, a Hernán B. Rodríguez,* a,b and Enrique San Román*a Accepted a INQUIMAE (UBA-CONICET) / DQIAyQF, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, Buenos Aires, Argentina b INIFTA (UNLP-CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Diag. Sciences 113 y Calle 64, La Plata, Argentina Photobiological Corresponding Authors & * Enrique San Román, E-mail: [email protected] , Tel.
    [Show full text]
  • Combination of Ultra-High Pressure and Xanthene-Derivatives to Inactivate Food-Borne Spoilage and Pathogenic Bacteria
    COMBINATION OF ULTRA-HIGH PRESSURE AND XANTHENE-DERIVATIVES TO INACTIVATE FOOD-BORNE SPOILAGE AND PATHOGENIC BACTERIA DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Joy Gail Waite, M.S. * * * * * The Ohio State University 2007 Dissertation Committee: Approved by Professor Ahmed E. Yousef, Adviser Professor Steven J. Schwartz _________________________________ Professor MacDonald Wick Adviser Food Science and Nutrition Graduate Program Professor Jeff Culbertson ABSTRACT Food processing methods can lead to the development of processing-resistant spoilage and pathogenic microorganisms that can cause further cost to processors and increased health risks to consumers. Thus, inactivation of these potentially problematic bacterial strains by combinations of physical and/or chemical treatments needs to be investigated. Previous studies have shown combination treatments of ultra-high pressure (UHP) with antimicrobial peptides, oxidants, and antioxidants to be efficacious at inactivating bacteria. The current study investigates the use of UHP in combination with hydroxyxanthenes, including FD&C Red No. 3, to inactivate pressure-resistant strains of Lactobacillus plantarum, Listeria monocytogenes, and Escherichia coli O157:H7. Combination treatments of UHP (400 MPa, 3 minutes) and FD&C Red No. 3 (3 to 10 ppm) resulted in significant enhancement of inactivation of several pressure-resistant Gram-positive and Gram-negative strains. FD&C Red No. 3 is a known photosensitizer and was capable of inactivating Gram-positive species with short exposure to ambient light (15-30 minutes); however this compound had no effect on Gram-negative species without UHP treatment. UHP was found to cause an irreversible change in the barrier properties of the outer membrane with pressure treatments above 250 MPa leading to accumulation of FD&C Red No.
    [Show full text]