Experimental Reports Brazilian Journal of Case Reports ISSN: 2763-583X. doi: 10.52600/2763-583X.bjcr.2021.1.4.135-152. This is an open access article under the CC BY license by Creative Commons Attribution 4.0 International License. In vitro antifungal activity of Candida culture extracts against Trichophyton rubrum and Trichophyton mentagrophytes Thiago Henrique Lemes 1, Guilherme Silva Torrezan 1, Carlos Roberto Polaquini 1, Luis Octavio Regasini 1, Bianca Gottardo de Almeida 1, Natália Seron Brizzotti-Mazuchi 2, Mariela Domiciano Ribeiro 2, Taiza Maschio-Lima 1, Maicon Henrique Caetano 1, Veridianna Camilo Pattini 1, Mario Henrique Paziani 3, Marcia Regina von Zeska Kress 3, João Paulo Zen Siqueira 2, Margarete Teresa Gottardo Almeida 2 1 São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences (Ibilce), São Paulo, SP, Brazil. 2 Department of Infectious, Parasitary and Dermatology Diseases, São José do Rio Preto Medical School (Famerp), São Paulo, SP, Brazil. 3 Department of Clinical Analysis, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo (USP), São Paulo, SP, Brazil. *Corresponding author: Thiago Henrique Lemes. Av. Brigadeiro Faria Lima, – 5416 – Vila São Pedro CEP: 15090- 000, São Paulo, SP, Brazil. Phone: +55 (17) 32015843. E-mail: th.lemes@unesp.br. Research Ethics Committee Approval: Not applicable. Received on: Oct 11, 2021. Accepted on: Oct 31, 2021. Available online: Nov 15, 2021. Abstract Onychomycoses are nail infections caused primarily by dermatophytes fungi, yeasts, and other filamentous fungi, characterized by persistent infections, prolonged therapy, and high recurrence rates. In clinical practice, some of these occurrences present two or more microorganisms, and the interactions among them can change the chemical environment mediated by small diffusible molecules, producing a competitive niche. The aim of this study was to evaluate the antifungal activity of individual extracts of pure cultures of Candida albicans and C. parapsilosis against dermatophytes. To obtain the fungal extracts, cultures were filtered through a 0.2 μm membrane and submitted to liquid-liquid extraction using ethyl acetate. The Minimal Inhibitory Concentration (MIC) of each extract was evaluated by broth microdilution method and checkerboard assay with fluconazole against clinical isolates of Trichophyton rubrum and T. mentagrophytes. The invertebrate model of Galleria mellonella was used to evaluate the toxicity of the extracts. As results, the extracts of C. albicans and C. parapsilosis showed antifungal activity with MICs between 31,2 – 2000 μg/mL. In association with fluconazole, synergistic effect was detected for all combinations. The extracts presented low toxicity in G. mellonella. In the future, isolation and identification of the extract compounds may allow new therapeutic approaches in the control of fungal infections. Keywords: Onychomycoses; Dermatophytes; Yeast; Antifungal activity.