A new ultra-high pressure liquid chromatography method for the determination of antioxidant flavonol aglycones in six Lysimachia species

Abstract

UPLC-DAD method was developed and validated for the quantitative determination of free flavonol aglycones (kaempferol, quercetin and myricetin) after acidic hydrolysis in six Lysimachia species. Quantitative analyses showed that the amounts of various flavonol aglycones were significantly different in Lysimachia vulgaris, Lysimachia nummularia, Lysimachia punctata, Lysimachia christinae, Lysimachia ciliata and Lysimachia clethroides. The L. clethroides sample was found to be the richest in kaempferol (25.77 ± 1.29 μg/mg extract) and quercetin (97.67 ± 4.61 μg/mg extract), while the L. nummularia sample contained the highest amount of myricetin (20.79 ± 1.00 μg/mg extract). The antioxidant capacity of hydrolysed extracts was evaluated using in vitro DPPH^• (2,2-diphenyl-1-picrylhydrazyl) and ABTS^•+ [2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)] decolourisation tests. The observed radical scavenging capacities of the extracts showed a relationship with the measured flavonol aglycone content and composition. The acidic treatment resulted in an increased free radical scavenging activity compared to the untreated methanol extract.

Keywords:

• UPLC
• Lysimachia
• flavonoid
• antioxidant
• loosestrife

Acknowledgement

The authors render thanks for the Garden of Medicinal Plants, Jagiellonian University, Cracow, Poland for the L. ciliata and L. clethroides herb samples.

Funding

This work was supported by the OTKA [grant number PD 109373].