Atividade antifúngica e investigação da segurança do cinamaldeído na forma isolada e de pomada orabase: um estudo in vitro, in vivo e clínico fase I

• Ano de defesa: 2021
• Autor(a) principal: Alves, Danielle da Nóbrega
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraíba; Brasil; Farmacologia; Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos; UFPB
• Palavras-chave em Português: Candidíase oral; Produtos antimicrobianos; Antifúngicos; Produtos biológicos; Toxicologia; Oral candidiasis; Antimicrobial products; Antifungal; Biological products; Toxicology; CNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIA
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/123456789/21075

Objective: To evaluate the antifungal activity and investigate the safety of cinnamaldehyde in isolated for in orabase ointment through an in vitro, and in vivo and clinical phase I study. Methods and results: The interference of cinnamaldehyde on fungal micromorphology and its ability to reduce biofilm was evaluated in vitro analysis. For the cytotoxicity study, the hemolysis test was performed on human erythrocytes. Micro-cultures treated with cinnamaldehyde demonstrated impaired cell development, with rare pseudohyphae expressions and the absence of chlamydoconidia. Cinnamaldehyde reduced biofilm by 64.52% to 33.75% (p <0.0001) at low concentrations (378.3-151.3 μM) and was not cytotoxic to erythrocytes. Acute toxicity has already been assessed in studies with Galleria mellonella larvae and Danio rerio embryos (zebrafish), and genotoxicity has been assessed in a mouse model. The pharmaceutical formulation (orobase ointment) containing cinnamaldehyde was evaluated for verification of antifungal activity in vitro, and for toxicity in keratinized oral rat mucosa. Cinnamaldehyde was not toxic at the highest dose tested (20 mg/kg) in Galleria mellonella larvae and did not present genotoxicity up to a dose of 4 mg/kg in the mouse model. However, it was found to be toxic in zebrafish embryos up to a concentration of 0.035 μg/mL; LC50 0.311 μg/m; EC50 0.097 μg/mL (Egg hatching delay); 0.105 μg/mL (Pericardial edema). In the orabase antifungal susceptibility test, cinnamaldehyde exhibited activity in concentrations greater than 200 μg/ml. As for safety in an animal model with rats, the orobase ointment proved to be safe for use on keratinized mucosa up to the maximum concentration tested (700 μg/mL.), The clinical trial was carried out in 35 individuals with healthy oral mucosa divided into three groups: 200μg/mL ointment, n = 12; 300μg/mL, n=11 and 400μg/mL, n=12. Product safety was assessed by three parameters: (a) clinical evolution recorded by trained examiners; (b) evolution of the inflammatory processes registered by an exfoliative cytology exam and analysis by trained pathologists; (c) Candida spp. Colony Forming Units (CFUs) verification The three parameters were analyzed before treatment and at 15 days afterwards. The clinical mucosa examination showed that the three concentrations of the ointments triggered no inflammatory processes or undesirable events. Mycological analysis revealed a reduction of at least 99% in the number of CFUs for the volunteers. In the analysis by exfoliative cytology, the cells were healthy. The participants reported a pleasant taste though 17% reported a slight burning sensation when applying the product. Conclusions: Cinnamaldehyde presented antifungal activity, demonstrating its ability to reduce biofilm and alter fungal micromorphology. In addition, it was not cytotoxic to human erythrocytes, nor toxic in animal models with vertebrates (exception the zebra fish) and invertebrates, nor did it present genotoxic activity. In addition, when used in the form of an ointment in orabase, with recognized antifungal activity against Candida albicans, it did not present clinical or histological evidence of inflammation in animal mucosa. In the human model, the ointment in orabase containing cinnamaldehyde was found to be safe and tolerable for used in phase II clinical trials to prove its effectiveness in prosthetic stomatitis treatment.