Polyphenol Composition and Antioxidant Capacity of Three Lysimachia Species

The polyphenol composition and antioxidant properties of three Lysimachia species (L. nummularia L., L. vulgaris L. and L. punctata L.) and their column chromatographic fractions were investigated. The antioxidant activity of herb extracts and 54 different column chromatographic fractions was evaluated using in vitro DPPH• and ABTS•+ decolorization tests. The total polyphenol content was determined by spectrophotometric methods. The phenolic compounds of extracts of different Lysimachia species and their bioactive fractions were characterized by online chromatographic methods. For identification of the compounds, UV spectral data, accurate molecular mass and formula, as well as MS and fragmentation patterns given by LC-DAD-ESI/MS/MS and LC-ESI-TOF analyses were used. Quantification of the compounds was performed by LC-DAD using an external standard method. In the extracts, caffeic acid derivatives, chlorogenic acid, free flavonoid aglycones, and 11 various flavonoid glycosides were identified. Flavonoid composition of Lysimachia extracts showed significant differences. L. punctata extracts had the strongest DPPH• and ABTS•+ radical scavenger activity (IC50=43.3 μg/mL and 21.3 μg/mL), due to their high myricitrin and quercetin-hexoside content. Correlation between polyphenol content and radical scavenging activity of each column chromatographic fractions is also included.