Antimicrobial effect of essential oil, nano-emulsion of essential oil and green synthesis of copper (Cu) nanoparticles produced from aqueous extract of Salvia mirzayanii

BACKGROUND AND OBJECTIVESNowadays, due to the resistance of bacteria to conventional antibiotics and antimicrobial agents, many researches are being conducted to find new types of effective antimicrobial agents. Copper has been increasingly used in the form of nanoparticles with high antimicrobial activity and cheap price against all Gram-negative and Gram-positive bacteria. Salvia mirzayanii is one of the medicinal species of mint family and its antimicrobial effects have been proven. In this research, the effect of essential oil, nanoemulsion of essential oil and green synthesis of copper nanoparticles produced from the aqueous extract of Salvia mirzayanii along with the standard antibiotic gentamicin on Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) was performed.MATERIALS AND METHODSThe essential oil of Salvia mirzayanii was prepared in the laboratory. Microdilution method was used to check MIC and MBC of essential oil against the three mentioned bacteria. For the synthesis of essential oil nanoemulsion and copper nanoparticles, the aqueous extract of Salvia mirzayanii was used in laboratory. The data was analyzed by SPSS version ۲۶ software, descriptive statistics tests, average standard deviation and analytical statistical tests of analysis of variance.RESULTS AND DISCUSSIONThe results of essential oil analysis showed that the main compounds were phenolic monoterpenes. The essential oil prepared from Salvia mirzayanii did not have any inhibitory effect against P. aeruginosa, but the average MIC, MBC and ZOI of Salvia mirzayanii essential oil against E. coli were in the range of ۵۰۰, ۵۰۰, ۱۱.۴-۹.۴ microliters/ml, respectively. Also, the MIC, MBC and ZOI of Salvia mirzayanii essential oil against S. aureus were ۲۵۰, ۲۵۰-۵۰۰ and ۱۳.۵-۱۷.۵ microliters/ml, respectively. The results showed that in all bacteria, the lowest inhibitory effect was related to the essential oil and the highest inhibitory effect was related to the antibiotic gentamicin. The analysis of produced copper nanoparticles confirmed the green synthesis of nanoparticles in the range of nanoparticles.CONCLUSIONThe findings of this research showed that the aqueous extract of Salvia mirzayanii has a high potential in the production of copper nanoparticles. Also, due to the antibacterial properties of essential oil, nanoemulsion of essential oil and copper nanoparticles biosynthesized from the extract of Salvia mirzayanii, it can be used as a supplement to antibacterial drugs.