Abstract
Objectives: This work aimed to evaluate the antibacterial, antifungal, and anti-Mayaro virus (MAYV) activity of rutin, a flavonoid isolated from the leaves of Tontelea micrantha (Celastraceae). Materials and Methods: The antibacterial and antifungal activities were evaluated by the broth microdilution method through the determination of the minimum inhibitory concentration. The anti-MAYV activity was determined by the rutin concentration required to protect 50% of the cells after viral infection. The indirect 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay was used to determine the cytotoxic concentration of rutin to 50% of Vero and BHK cells. The antimicrobial activity spectrum of rutin was predicted using the online software prediction of activity spectra for substances (PASS). Results: Although the PASS prediction had shown that a higher probability of rutin acts as an antifungal agent, the in vitro assays showed no antimicrobial activity. Regarding the cytotoxicity assay, rutin was not toxic to Vero and BHK cells. Conclusions: Many biological activities have been described for flavonoids, but the flavone rutin did not show antimicrobial activity in vitro. The results obtained in this work suggest that rutin is not a promising antimicrobial agent.

Key words: Antibacterial activity, antifungal activity, anti-Mayaro virus activity, rutin