Phenolic content, antimicrobial and antioxidant activities ofHypericum perfoliatum L.

Phenolic composition of three extracts of Hypericum perfoliatum was investigated; moreover also their antimicrobial and antioxidant activities were evaluated. The chloroform-methanol and methanol extracts showed antioxidant activity (IC50less than 35 g/mL), probably due to the presence of flavonoids,namely hyperoside (1.6 mg/mL in both extracts) and phenolic acids, such as chlorogenic acid (0.4and 0.5 mg/mL, respectively). On the contrary, chloroform extract did not show remarkable antioxi-dant activity. Chloroform and chloroform-methanol extracts exhibited antimicrobial activity againstthe Gram positive Bacillus cereus (strains DSM 4313 and DSM 4384) and S. aureus and the Gram neg-ative Escherichia coli and Pseudomonas aeruginosa strains, as well as against the emergent pathogenChronobacter sakazakii.