3.3. Fungistatic Activity against R. mucilaginosa IHEM 18459 and Correlation with Structure and In Silico Data

The compounds 1–8 were screened for their antimicrobial activity using the microdilution method with modified CLSI guidelines [69]. The broth used for the tests included RPMI 1640 medium buffered with MOPS.

Different concentrations of compounds 1–8 were prepared in DMSO and then diluted 50 times in the medium. An amount of 100 microliters of each concentration was placed into the wells of 96-well microplates. R. mucilaginosa IHEM 18459 was cultivated on Sabouraud agar. The inoculum was made from a 24 h culture by a dilution to 0.5 McFarland and then further diluted to obtain a density of 1 × 10³–5 × 10³ CFU/mL. The inoculum volume pipetted into the previously placed antifungals was 100 µL. All the compounds were tested in triplicate. The plates were then incubated separately at 25 °C and 30 °C for 48 h using 1200 RPM. The activity was determined spectrophotometrically at a wavelength of 595 nm and determined as the half-maximal inhibitory concentration (IC₅₀).

The prediction of lipophilicity (Log P), solubility (log S), and CYP isoenzyme inhibition for compounds 1–8 was performed using the tool designed by the Swiss Institute of Bioinformatics at the University of Lausanne (http://www.swissadme.ch/index.php (accessed on 25 February 2023)), reported by Daina et al. [23].

The toxicity of rat cells was tested using the computational tool GUSAR (General Unrestricted Structure-Activity Relationships: http://www.way2drug.com/gusar/index.html (accessed on 25 February 2023)) as part of the Way2Drug platform, as reported by Druzhilovskiy et al. [22].