| Congresso Brasileiro de Microbiologia 2023 | Resumo: 111-2 | ||||
Resumo:Antifungal resistance poses a significant challenge, significantly limiting the available treatment options for fungal infections. The slow and expensive development of new antifungal drugs further exacerbates this problem. However, biotransformation using fungi presents a promising approach to overcome this challenge. By modifying known molecules like lapachol, fungi can generate novel compounds with enhanced antifungal properties. This study aimed to assess the antifungal activity of biotransformed lapachol by Aspergillus niger against two pathogenic yeasts. The A. niger LM5826 strain was sourced from the Collection of Microorganisms of Medical Interest - INPA and lapachol and fluconazole were obtained from Sigma-Aldrich. A. niger LM5826 was cultured in PDA medium at 28°C for 7 days. Inoculum preparation involved adding 1x104 cells/mL of A. niger to 50 mL of Czapeck broth in Erlenmeyer flasks. The experiment included four variants: simultaneous inoculation of fungus and lapachol (50 μg/mL), fungus growth followed by lapachol addition, only fungus with medium, and only lapachol with medium. All variants were incubated at 28°C with constant agitation for 7 days and subsequently separated from the mycelium using a paper filter. The broths underwent three rounds of ethyl acetate extraction (v/v) and were concentrated using a rotary evaporator. The antifungal activity was evaluated using the well-diffusion method as per the Clinical and Laboratory Standard Institute protocol (M44). Inoculum of Candida albicans ATCC 60193 and Cryptococcus gattii (VNI) WM148 was prepared and spread on petri dishes containing Sabouraud agar. Wells with a diameter of 5 mm were created using a sterilized pipette tip, and 200 μl of each extract (1 mg/mL) was added, along with a negative control (10% dimethyl sulfoxide) and a positive control (fluconazole). After incubation at 35°C for 24/48 hours, the inhibition zones were measured using a digital caliper. Fluconazole exhibited 9 mm inhibition zones against C. albicans, while Cryptococcus gattii showed an inhibition zone of 21 mm. Lapachol displayed inhibition zones of 21 mm for both yeasts. Notably, the fungus extract alone showed values of 24 mm against C. albicans, while simultaneous incubation with lapachol resulted in an increased inhibition zone of 37 mm. Cryptococcus gattii exhibited similar values with 38 mm for the same extracts. Aspergillus genus has demonstrated its capability to biodegrade lapachol into two known secondary metabolites with antimicrobial activity. Additionally, this species is known to produce gliotoxin, a potent antifungal agent. Biotransformation processes offer a simple and effective approach to overcoming antifungal resistance. Further studies are necessary to gain a better understanding of the biochemical processes involved in the formation of antifungal metabolites. Given the growing prevalence of multidrug-resistant organisms, the search for new molecules with potent antifungal activity remains crucial. Palavras-chave: Antifungal activity, Bioprocess, Biotransformation, Naphthoquinone, Resistance Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior | |||||