Azure dyes as new photosensitizer prototypes to application in photodynamic therapy againstCandidaspp.

Leonardo M Moreira,Maricília S Costa,Hueder P.M De Oliveira,Lúcia Codognoto,Juliana P Lyon,Isis Trajano,Suellen M.S Tursi,Monalisa P Felipe,Máira R Rodrigues

doi:10.1155/2010/395831

Abstract

Infections caused byCandida albicansare of increasing concern, especially considering immunodepressed patients. The toxicity of most antifungal agents, the great number of cases with recidives, as well as the emergence of resistant samples has provoked the evaluation of new forms of therapy. In this context, the photodynamic therapy (PDT) presents auspicious antimicrobial properties, stimulating the development of trials employing several kinds of photosensitizers. In the present work, the application of different kind of Azure dyes as photosensitizer in PDT againstC. albicanswas evaluated through instrumental measurements of electronic spectroscopy. In fact, the values of optical density were a precise indicator of the growth inhibition of the microorganisms. Indeed, Azures are phenothiazinium derivatives that constitute a very relevant class of compounds with several biomedical applications, such as photoantimicrobial therapy against local bacterial infection, tuberculosis, trypanosomiasis, malaria, Rickettsia, yeasts, viral infectionnand cancer. Azure A, Azure B, Azure A thiocyanate, Azure B BF4, Azure A eosinate are the dyes tested againstC. albicans. The results denoted completely distinct behaviors to the different types of Azure compound evaluated in this work. In fact, Azure A and Azure A eosinate presented significant results when irradiated with 56 J/cm2, since the growth inhibition ofC. albicansreached approximately 60%. This Azure compounds have significant potential to be employed as photosensitizer (PS) in PDT, especially in cases of mucocutaneous candidosis. The spectroscopic evaluation was very effective to the detection of slight alterations in the growth of the microorganisms, denoting that this kind of analysis is an excellent alternative to determine growth inhibition ofCandida albicans. The experimental data are discussed in details in agreement with recent results from literature.

Highlights

IntroductionSome factors are predisposing for the development of candidosis, such as immunodeficiencies, malignant diseases, radiotherapy, long-term treatment with antibacterial drugs and age extremes [13]
The increase in the number of infections caused by Candida species other than C. albicans contributed to the emergence of isolates that are resistant to amphotericin B and fluconazole [17]
This compound demonstrates an intermediary action, when compared with Azures A and B, since an irradiation 28 J/cm2 does not precludes the growth of C. albicans, which only occurs with 56 J/cm2

Summary

Introduction

Some factors are predisposing for the development of candidosis, such as immunodeficiencies, malignant diseases, radiotherapy, long-term treatment with antibacterial drugs and age extremes [13]. Both cutaneous and mucocutaneous candidosis may appear in healthy individuals with local predisposing conditions, such as denture wearing, moist wrinkles in skin and altered local pH [14]. Amphotericin B and azolics, such as ketoconazole, fluconazole and itraconazole, have been considered efficient in the treatment of both systemic and local candidosis. The increase in the number of infections caused by Candida species other than C. albicans contributed to the emergence of isolates that are resistant to amphotericin B and fluconazole [17]. It is important to notice that the treatment with antifungal drugs may be prolonged and recidives are very common

Methods

Results

Conclusion