In vitro antimicrobial and antioxidant activity of two selected plants from Lamiaceae species

The aim of the present study was to evaluate antimicrobial and antioxidant activity of Melissa officinalis L. and Mentha piperita L. from Lamiaceae species (The detection of antimicrobial activity was carried out by disc diffusion method and evaluation of minimal inhibition concentration against five Gram-negative bacteria: Escherichia coli CCM 3988, Klebsiella pneumoniae CCM 2318, Salmonella enterica subsp. enterica CCM 3807, Shigella sonei CCM 1373, Yersinia enterocolitica CCM 5671 and five Gram-positive bacteria: Bacillus thuringiensis CCM 19, Clostridium perfringens CCM 4435, Haemophilus influenzae CCM4456, Listeria monocytogenes CCM 4699, Staphylococcus aureus subsp. aureus CCM 2461. Antioxidant activity was determined by DPPH radical scavenging and phosphomolybdenum antioxidant methods. The content of polyphenols and flavonoids was measured by colorimetric methods. Both tested plants showed the highest antimicrobial activity against Gram-negative bacteria confirmed by both methods - disc diffusion and minimal inhibitory concentration. Additionally, both tested plants exhibited high antioxidant activity. The highest content of total polyphenol (37.37 mg GAE/g g) was identified in lemon balm, but flavonoids (33.90 µg QE/g) in peppermint