Uniform size filter paper disks (3 disks per compound) were impregnated by equal volume (10 μL) from the specific concentration of dissolved tested compounds and carefully placed on inoculated agar surface.
The test was performed on medium potato dextrose agar (PDA) which contain infusion of 200 g potatoes, 6 g dextrose and 15 g agar [29] Uniform size filter paper disks (3 disks per compound) were impregnated by equal volume (10 µL) from the specific concentration of dissolved tested compounds and carefully placed on inoculated agar surface.
Concentrations ranging from 5 to 800 μg/mL for antibacterial activity tests, and 50 to 2000 μg/mL for antifungal activity tests were employed by dissolving the test samples in DMSO.
Stock concentration of the test items Berberine and Curcumin and their combination in 1 : 1 ratio were prepared by dissolving the test item in 100% DMSO shown in Table 1 and final stock solution is prepared as shown in Table 2. 10% Sodium Lauryl Sulphate (SLS) (w/v) was used as positive control and different concentrations of SLS were used (10, 5, 2.5, 1.25, 0.625, and 0.312 percent solutions).
Furthermore, dissolving capability test, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and reducing power assay, solvent residue test were also carried out.
The 2.5% NaOCl solution was substantially more effective than the three 0.5% solutions in dissolving the test tissues.
These include mixing the agent in the food, dissolving the test compound in the drinking water, or administering the material by gavage.
The antimicrobial agent stock solution was prepared by dissolving the test agent in the appropriate solvent (water for ciprofloxacin, ethanol for chloramphenicol) [ 24].
DMSO was used for dissolving the tested compounds and showed no inhibition zones, confirming that it has no influence on growth of the tested microorganisms.
For nanoparticles that dissolve in testing media, acute toxicity tests should be conducted not only using a freshly prepared suspension of nanoparticles in test medium, but also an aged suspension where nanoparticles are added to the media for example 1 3 days prior to testing.
