Determination of polyphenols and in vitro antimicrobial and antioxidant activity of Calluna vulgaris (L.) Hull

Calluna vulgaris (L.) Hull belonging to Ericaceae family occurs mostly at sour habitats in subalpine regions in Europe. The species is cultivated in many countries, but it is known as medicinal plant because of polyphenols and aucubin as main compounds. In this work, the polyphenolic, flavonoid, and tannin content, as well as the antimicrobial and antioxidant activity of the aerial part, were evaluated. In phytochemical analyses, methanol extract showed the highest phenolic and flavonoid content, followed by ethanol, methanol/water, and aqueous extracts. In antimicrobial tests, chloroform, ethyl acetate, butanol, and water extracts inhibited the growth of S. aureus and MRSA , while butanol and water fractions were effective against E. coli , and water extract for E. coli ESBL and K. pneumoniae ESBL. Water extract showed the most inhibitory effect for the tested 2 g-positive and 3 g-negative strains including both bactericidal and bacteriostatic activity. Data analysed by Pearson coefficient correlation showed positive correlation between polyphenol and flavonoid content. The determined antioxidant capacity of the herb ranged from 0.145 to 0.296 mg/mL. The results highlight the significance of the plant as possible antioxidant source and as an antimicrobial agent for further studies.