Antimicrobial and antioxidant activity of the extracts from Origanum vulgare L . wild growing in Bosnia and Herzegovina

Antifungal, antimicrobial, insecticidal and antioxidant activities of Origanum vulgare L. provide the basis for suggesting that oregano plant extracts may be useful for prevention and treatment of infections. The main goal of this study was to determine antimicrobial and antioxidant activities of methanolic and aqueous extracts of the leaves and flowers of O. vulgare. Antimicrobial testing of plant extracts was done using well diffusion method. Activity of extracts was tested against Gram positive bacteria: Staphylococcus aureus ATCC 25923, methicillinresistant Staphylococcus aureus (MRSA) ATCC 33591, Bacillus subtilis ATCC 6633, Enterococcus faecalis ATCC 29212 and five Gram-negative bacteria: Salmonella abony ATCC 6017, Salmonella enterica serovar Enteritidis ATCC 31194, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 25922, extended-spectrum β-lactamase (ESBL) producing Escherichia coli ATCC 35218 and fungus Candida albicans ATCC 1023. Antibiotic ampicillin and antimycotic nystatin were used as positive control. The antioxidant activity was determined using the DPPH (1,1-diphenyl-2-picrylhydrazyl) method. The highest values for inhibition zone for methanolic and aqueous extracts were recorded for Gram positive B. subtilis, S. aureus and MRSA. Methanolic extracts exhibited antibacterial activity against tested Gram negative bacteria in variable degree while the growth of these bacteria was not inhibited by aqueous extracts. Tested fungus C. albicans was not sensitive to investigated oregano extracts. All the extracts showed moderate to potent antioxidant activity with methanolic flower extract demonstrating the strongest antioxidative activity with the IC50 value of 0.205 mg/mL. Therefore it can be concluded that flower and leaf oregano extracts have significant antibacterial and antioxidant potential. *Correspondence E-mail: renatabestagajevic@gmail. com