ClTI, um inibidor de tripsina tipo KUNITZ purificado a partir de sementes de Cassia leiandra BENTH., exerce efeito candidicida, induzindo estresse oxidativo e apoptose celular em C. albicans

Abstract

Protease inhibitors are multifunctional biomolecules found in all organisms responsible for inhibiting the catalytic action of enzymes involved in important physiological and pathological processes. These molecules can be used as a biotechnological tool for the control of microbial infections. In a hospital environment, opportunistic yeasts of the genus Candida carry a serious public health problem in the world. These microorganisms have become resistant to traditional antimycotics and are responsible for high rates of morbidity and mortality. The view of the urgent need for new antimicrobial therapies, the prospection and characterization of the biological activity of antifungal molecules, especially from vegetable, has intensified. In this context, several protease inhibitors have already been isolated from medicinal plants and have shown a promising anticandidal effect. In a previous study, a Kunitz trypsin inhibitor, ClTI, was purified from the seeds of Cassia leiandra Benth. The objective of this work is to evaluate the effect of ClTI on different Candida species, to investigate it mode of antifungal action and to evaluate its toxicity against human cells. ClTI interrupted the cell multiplication of Candida albicans, Candida tropicalis, Candida parapsilosis and Candida krusei at different intensities, demonstrating potent fungicidal effect for C. albicans. At the dose of MIC50 (2.1 μM) caused morphological changes, permeabilized the plasma membrane and altered the pumping of protons in C. albicans cells. For the same species, the inhibitor still induced the increased generation of reactive oxygen species, was able to degrade the genetic material and exhibited antibiofilm activity. No signs of toxicity were observed in human cells treated with ClTI. The data obtained demonstrate that the C. leiandra inhibitor has a great anticandidicidal potential, and may in the future become a medical product for the treatment of hospital infections caused by C. albicans.