Identification of punicalagin as the bioactive compound behind the antimicrobial activity of pomegranate (Punica granatum L.) peels

Extracts from ‘Zhéri’ and ‘Hicaznar’ varieties of pomegranate, Punica granatum L., were obtained by subjecting powdered peels to extraction using water, water/ethanol (1:1; v/v), ethanol, acetone heptane. Using the agar diffusion assay, extracts with water and/or ethanol shown display significant antimicrobial activity diameters inhibition zones up 20 mm. Ethanolic extracts, which most active, fractionated SPE, HPLC UHPLC, active compounds they contain identified mass spectrometry. Punicalagin, under its ? ? anomeric forms, was as antibacterial compound in pomegranate peel extracts. Both forms MIC values between 0.3 1.2 µg.ml?1, easily converted one other an ?/? equilibrium ratio 3/7. Their spectrum targeted 10 out 13 Gram positive two three negative bacteria well a yeast strain.