Polyphenols from Plants: Phytochemical Characterization, Antioxidant Capacity, and Antimicrobial Activity of Some Plants from Different Sites of Greece

Polyphenols are present in many plants and herbs, and the scientific community and consumers are aware of their health-promoting effects. Plants of Greek origin were studied for their polyphenol content and their antioxidant and antimicrobial activities. Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography coupled to a diode array detector (HPLC-DAD) were used for the identification and characterization of plant polyphenols. For GC-MS, a silylation procedure was employed. Ferulic acid, quercetin, and catechin were the most abundant polyphenols. The Rancimat test, FRAP (Ferric-reducing Antioxidant power) assay, and DPPH (2,2-Diphenyl-1-picrylhydrazyl) assay were used to study the antioxidant capacity, which was proven for all studied plants. The antimicrobial activity was studied against specific pathogenic microorganisms. Pelargonium purpureum and Sideritis scardica plant extracts inhibited most microorganisms such as L. monocytogenes and E. coli. Extracts of studied plants showed both antioxidant and antimicrobial activities; hence, they can be considered to be used by the food industry.