Volatile compounds detection with antibacterial activity in endophytic fungi associated with Costus spiralis / Detecção de compostos voláteis com atividade antibacteriana por fungos endofíticos associados à Costus spiralis

Abstract

- Endophytic fungi that live inside plants, for instance, in organs and plant tissues such as leaves and branches, without causing any harm. Assumptions of interactions between endophytic fungi and host plants suggest that therapeutic properties may be in the fungi and not on the plant or, probably, in the interaction amid them. Due to this, the interest in endophytic fungi from medicinal plants has increased. The gram-positive Streptococcus pneumoniae and gram-negative Klebsiella pneumoniae are important pathogenic bacteria, acting as infectious agents and causing respiratory diseases and hospital infections. This study aimed to obtain volatile compounds from endophytic fungi, which were isolated from medicinal plant Costus spiralis (jacq) Roscoe (Costaceae) and perform an antibacterial evaluation of them against S. pneumoniae and K. pneumoniae. The test to verify volatile substances was realized using Petri dishes without agar in the central portion, in order to prevent the diffusion effect. The endophytic fungus and the pathogen were inoculated on opposite sides of the plate that were sealed with parafilm. Negative controls were performed with each pathogen inoculation in culture media without antagonist, however, there was no growth inhibition of pathogens for those which were incubated in the presence of endophytic test, when comparing to control test. Thus, the discovery of new antibiotics becomes important due to the emergence of resistant pathogens, as well as the development of new diseases and the toxicity of drugs that already exist