| Abstract [eng] |
Antioxidant testing of natural products (such as plant extracts) has attracted increasing interest in recent years, mainly due to the fact that antioxidants can neutralise harmful free radicals in vitro, thus suggesting that an antioxidant-rich diet might provide health benefits. Nepeta and peony species presented in this work are insufficiently phytochemically characterized and poorly tested in a sense of their biological activity. Due to this fact the aim of this study was determined phytochemical composition and antioxidant also bio activity of Nepeta and peony species extracts. Traditional multi-step soxhlet extraction and novel accelerated solvent extraction (ASE) were used to produce natural extracts of Nepeta and peony species. Antioxidant activity of extracts were assayed using DPPH•, ABTS•+, ORAC, HORAC and HOSC, as well as the cellular antioxidant (CAA) method. The total content of phenolic compounds in the extracts was determined using the Folin-Ciocalteu reagent method. Antioxidant activity of solid residues were tested by QUENCHER approach method. Antioxidant activity of individual compounds were analysed by HPLC-DPPH• post column assay. Quantitative and qualitative analysis of Nepeta and peony species extracts were analysed by ultra performance liquid chromatography coupled with mass quadrupole time of flight detector (UPLC-Q-TOF). Inhibitory effect of investigated extracts were analysed using α-amylase assay and IC50 values was determined. Cytotoxic properties of obtained extracts after 4, 24 and 48 hours of incubation were evaluated using cytotoxicity assay and antiproliferative effect was evaluated in human colon carcinoma HT29 cell line. The evaluation of the antioxidant activity of obtained extracts by various in vitro methods the highest activity showed extracts extracted by polar solvents, while the lowest activity possessed acetone extracts. Solid fractions evaluated by Quencher approach showed that peony leafs fractions have higher antioxidant activity than thus of rest. Qualitative analysis showed that the main compounds of Nepeta species were phenolic acids such as rosmarinic, chlorogenic, caffeic, ferulic and etc., while in peony extracts were gallic acid derivatives such as methyl digallate, digallic acid, galloylhexose etc. Quantitative analysis of Nepeta species showed that ferulic acid was the main compound in water and acetone extracts, while rosmarinic acid was the main compound in methanol extracts. The highest amount of reported compounds were found in N. racemosa, N. nuda, N. sibirica and N. melissifolia extracts. In bio assays was determined that: peony leaf extract after traditional extraction with methanol possessed the highest inhibitory activity against α-amylase. In cytotoxicity studies N. melissifolia after 48 h of incubation have cytotoxicity on Caco-2 line cells. (IC50 6.98 mg/mL) and the best antiproliferative effect was determined in water extract of N. nuda (ED50 2.75 mg of extract/mL). It may be concluded, that peony and Nepeta species are a good source of antioxidant compounds and may be promising as bioactive ingredients in food and pharmaceutical industries. |
