Pleurotus sajor-caju can be used to synthesize silver nanoparticles with antifungal activity against Candida albicans

Green synthesis of silver nanoparticles (AgNPs) has become widely practiced worldwide. In this study, AgNPs were synthesized using a hot-water extract of the edible mushroom Pleurotus sajor-caju. The product, PSC-AgNPs, was characterized by using UV-visible spectra, dynamic light scattering analysis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectrometry. To assess its antifungal activity against Candida albicans, gene transcription and protein expression analyses were conducted for CaICL1 and its product, ICL, using real-time quantitative polymerase chain reaction and western blot, respectively.

PSC-AgNPs with an average particle size of 11.68 nm inhibited the growth of the pathogenic yeast C. albicans. Values for minimum inhibitory concentration and minimum fungicidal concentration were 250 and 500 mg L^-1 , respectively. TEM images revealed that the average particle size of PSC-AgNPs was 16.8 nm, with the values for zeta potential and the polydispersity index being -8.54 mV and 0.137, respectively. XRD and FTIR spectra showed PSC-AgNPs to have a face-centered cubic crystalline structure. The polysaccharides and amino acid residues present in P. sajor-caju extract were found to be involved in reducing Ag⁺ to AgNP. Both CaICL1 transcription and ICL protein expression were found to be suppressed in the cells treated with PSC-AgNPs as compared with the control.

Our PSC-AgNP preparation makes for a promising antifungal agent that can downregulate isocitrate lyase. © 2017 Society of Chemical Industry.