Antimicrobial effect of aqueous and methanolic extracts of white tea on standard and clinical strains involved in wound infection

Background and Aim : Skin health is important as the body's first line of defense. Treatment of skin wound infections is one of the major concerns of medical science. The use of antibiotics is a common treatment method, but today, due to the increase in antibiotic resistance, in most cases, early treatment is not achieved. Therefore, efforts to reduce the use of antibiotics by replacing natural active ingredients can be worthwhile. Medicinal plant extracts are considered due to having active ingredients with antimicrobial, anti-inflammatory, and antioxidant properties, as well as their easy availability and reasonable price. The aim of this study was to investigate the antimicrobial effect of white tea extract on standard and clinical strains isolated from purulent wound secretions.Methods : In this study, aqueous and methanolic extracts of Iranian white tea leaves were prepared by maceration method and their antimicrobial activity was evaluated by disk diffusion and agar well diffusion methods. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were evaluated by microdilution method. Bacteria included standard strains of Staphylococcus aureus (ATCC ۲۵۹۲۳), Pseudomonas aeruginosa (ATCC ۲۷۸۵۳), Klebsiella pneumoniae (ATCC ۱۳۸۸۳) and Escherichia coli (ATCC ۲۵۹۲۲), and their clinical strains isolated from purulent wound secretions.Results : Aqueous and methanolic extracts of white tea showed antimicrobial effect on all strains. The most antimicrobial effect was related to aqueous extract of white tea on standard Staphylococcus aureus and the concentration of ۵۰ mg / ml of this extract resulted in an average diameter of growth inhibition zone in the disk diffusion method and agar well diffusion method of ۲۴.۳ mm and ۲۹.۶ mm, respectively. The MIC and MBC of this extract on this bacterium were ۲۵ and ۵۰ mg / ml, respectively. Conclusion : The aqueous extract of white tea had the most antimicrobial effect on the studied strains, especially gram-positive bacteria. Therefore, it can be used in the preparation of medicinal ointments with topical application at the site of wound infection after assessment of its efficacy and safety in the laboratory mice and then volunteer patients having purulent wound.