Antifungal effects of Zataria multiflora Boisss (Shirazi Thyme) extract against Aspergillus fumigatus Afs35 genes: crza and rpda

Aspergillus fumigatus causes a fatal infection particularly among immunocompromised individuals. Nowadays herbal and medicinal essential oils play a vital role as an alternative safe medication. Zataria multiflora Boiss essential oils have antifungal activities mainly on the expression of some gene required for fungal survival. The main objective of the study was evaluation of antifungal effects of Z. multiflora Boiss extract against A. fumigatus AfS35 strain. The strain was obtained from department of biology, Baghdad University. Various concentrations (10-300mg/mL) of Z. multiflora Boiss extract were prepared and the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined using micro-broth dilution method. The expression of crzA and rpdA genes was evaluated using the quantitative real-time PCR (RT-qPCR) technique. The concentrations ≥100mg/mL of extract inhibited the fungal growth which was non-toxic to normal cell line (MIC=100mg/mL and MFC=150mg/mL). The combination of 50mg/mL of extract plus each of amphotericin B (10mg/ml) and nystatin (10mg/mL) significantly decreased the MIC level (p<0.001). The concentration of 10mg/mL of the extract decreased the expression of crzA and rpdA genes 2.4 (p<0.001) and 3.6 (p<0.0001) fold, respectively. The same concentration of amphotericin B non- significantly decreased the crzA and rpdA genes expression by 0.6 (p=0.224) and 1.1 (p=0.033) fold, respectively. The study concluded that Z. multiflora Boiss extract exerted antifungal effect against A. fumigatus by inhibiting the cell wall biosynthesis (down-regulation of crzA), sustainability and virulence expression (rpdA). The combination therapy with Z. multifora Boiss is promising to eradicate A. fumigatus infections.