*4.8. Assay of Antimicrobial and Antioxidant Activities*

Antimicrobial activities of compounds **1** and **2** were tested by the micro broth dilution method, as mentioned in the previous study [43]. The microorganism suspension (198 μL, 106 cfu/mL) in MH medium (Casein Acid Hydrolysate 17.5 g/L, beef extract 2 g/L, soluble starch 1.5 g/L, pH 7.3) was added to each well of 96-well plates. Solutions (6 mM) of the compounds and positive drugs were made up in DMSO and dispensed into 96-well plates to provide 16 concentrations in the range of 30–0.02 μM. Incubated at 28 ◦C for 9 h (*Candida albicans* in 37 ◦C for 12 h), the growth inhibition was recorded.

In the DPPH scavenging assay, samples to be tested were dissolved in MeOH and the solution (160 μL) was dispensed into wells of a 96-well microtiter tray. Forty microliters of the DPPH solution in MeOH were added to each well. The mixture was shaken and left to stand for 30 min. After the reaction, absorbance was measured at 510 nm, and the percent inhibition was calculated. ED50 values denoted the concentration of sample required to scavenge 50% of the DPPH free radicals [44].
