Substratos gastos de Pleurotus spp. como uma nova abordagem de saúde única para combater Aspergillus flavus micotoxigênicos.

Abstract

Food loss is a critical global concern, directly impacting food security and the sustainability of agricultural production. Aspergillus flavus plays a central role in this problem, as it contaminates corn crops with aflatoxins, posing risks to public health and the agricultural economy. The agricultural fungicide carboxin (CBX) faces significant challenges due to the emergence of resistant fungal strains, requiring more sustainable and effective alternatives. This study sought to investigate the antifungal efficacy of spent mushroom substrates (SMS) of Pleurotus ostreatus (SGPo) and P. djamor (SGPd), grown on banana leaves, when combined with CBX in combating A. flavus strains isolated from corn. The study involved obtaining and preparing banana leaf-based substrates for the cultivation of P. ostreatus and P. djamor mushrooms. The mushrooms were grown under controlled conditions and their extracts were obtained by maceration in hydroalcoholic solution. The chemical profile of the extracts was analyzed by ¹H Nuclear Magnetic Resonance (¹H NMR), while the presence of biogenic amines was evaluated by High Performance Liquid Chromatography (HPLC). For analysis of antifungal activity, the extracts were tested against different strains of A. flavus alone and in combination with Carboxin, using microdilution tests to determine the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC). Additional studies evaluated the effect of the extracts on conidial germination, mycelial growth and irritant potential through the HET-CAM test. The SGPo and SGPd extracts showed low levels of biogenic amines and a global profile analyzed by 1H NMR, evidencing the presence of volatile oils, unsaturated fatty acids, polysaccharides, oligosaccharides, tannins and flavonoids. The A. flavus strains analyzed demonstrated resistance to amphotericin B and itraconazole. However, SGPo and SGPd exhibited fungicidal activity against all strains tested, with Minimum Inhibitory Concentration (MIC) values ​​ranging from 102μ to 20μ mg/L. CBX also demonstrated fungicidal activity, with MIC values ​​between 32 and ő12 mg/L. No antagonism was observed between the CBX+SGPd and CBX+SGPo combinations. Furthermore, SGPo and SGPd significantly inhibited conidial germination and mycelial growth, with the CBX+SGPd and CBX+SGPo combinations being more effective than the agents tested individually (p < 0.0Ω). The reduction in conidial germination and mycelial growth exceeded 70% when the substrates were applied. The irritation potential of the agents was evaluated using the HET-CAM model, classifying SGPo and SGPd as moderate irritants. The findings of this study indicate that SGPo and SGPd can contribute to reducing the dosages and frequency of CBX application, promoting a more sustainable antifungal treatment, with lower environmental risks and less selective pressure for the development of resistance. These results are in line with the One Health approach, which seeks integrated solutions for human, animal and environmental health.