| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1068-1 | ||||
Resumo:Several species of yeasts, such as those belonging to the genus Candida, can cause severe systemic infections in immunocompromised patients, in addition to causing localized or disseminated infections such as candidiasis, meningitis, blood infections, among others. The misuse and uncontrolled use of conventional antibiotics has increased fungal resistance, and some of the most effective agents are also toxic increasing the need for studies of alternative compounds for the treatment of these diseases. To minimize such damage, many studies have focused on the analysis of antifungal proteins from different plant sources. Among these molecules are protease inhibitors (PIs). Thus, the present work aims to evaluate the mechanism of action and the antimicrobial activity of PIs isolated from Capsicum chinense seeds, on the growth of yeasts of the genus Candida. The PIs were extracted from seeds and submitted to reverse-phase chromatography, an HPLC system. Were identified PIs present in the peptide-rich fractions called PEF1, PEF2 and PEF3. In this work, analysis of antimicrobial activity and cell viability was carried out. Subsequently, the mechanism of action by which the PIs cause the death of the tested yeasts was evaluated. To visualize if the inhibitors present in the PEF2 and PEF3 inhibit the proteases of the genus Candida, the inhibitors were added to the yeast extract and visualized in the zymography. Cytotoxicity was also determined for erythrocytes and in vivo toxicity using Galleria mellonella larvae. PEF2 and PEF3 showed inhibitory activity against the yeasts C. albicans, C. tropicalis and C. buinensis. Were observed for C. tropicalis and C. buinensis, that the inhibitory effect is fungicidal. The fractions induced morphological changes, caused membrane permeabilization, increased ROS, and late apoptosis in the yeast C. tropicalis. The C. tropicalis extract has proteins with significant proteolytic activity and this activity is significantly inhibited mainly by the PI present in PEF2. In vitro, PEF3 showed low cytotoxicity for mammalian cells, even at high concentrations. In vivo, preliminary assay on PEF3 toxicity were tested using G. mellonella larvae. Both results confirmed the absence of toxicity at the tested concentrations. From the results obtained here, we intend to contribute to the understanding of the action of PIs in the control of fungal diseases of medical importance, helping to establish guidelines for the application of AMPs in the treatment of these diseases. Palavras-chave: anti-Candida activity, low toxicity, membrane permeabilization, plant antimicrobial peptide Agência de fomento:UENF, FAPERJ, CAPES, CNPq | |||||