The roots of licorice (Glycyrrhiza glabra L.) have been widely used in traditional and officinal medicines for the treatment of different diseases. Natural deep eutectic solvents (NADES) have become popular for the extraction of active principles from medicinal plants. However, the ability of NADES to co-extract trace elements during the isolation of target active compounds is rarely investigated. The aim of this study was to analyze the content of trace elements in acid-based NADES extracts from the roots of G. glabra and the health risks associated with them. In this study, we have tested for the first time the ability of several acid-based NADES to co-extract glycyrrhizic acid (GA) and trace elements from the roots of G. glabra. GA has been identified as the dominant phytochemical in G. glabra NADES extracts (0.145–0.495 mg/g). Due to the close pKa of lactic acid and GA, the yield of GA in lactic acid-based NADES was higher in comparison with other tested NADES. The yield of GA in NADES3-NADES5 was statistically significant and surpassed the yield of GA in water. The recovery of all elements (except Li) by all tested NADES was low (less than 6%). According to an ANOVA test, the hydrogen bond donor type plays a decisive role in the extraction of elements. A strong positive correlation between the recovery of GA and MPI was noted. The metal pollution index, hazard quotient, hazard index, and chronic daily intake were calculated and suggest that all tested NADES extracts of G. glabra roots were nontoxic and possess no health risk for both ingestion and topical application.

Water avens (Geum rivale L.) is a common Rosaceae plant widely spread in Europe and North America. It is rich in biologically active natural products, some of which are promising as prospective pharmaceuticals. The extracts of water avens are well known for their triterpenoid metabolites and associated anti-inflammatory, antimicrobial and antioxidant activities. However, the polyphenolic profiles of G. rivale L. are still awaiting complete characterization. Accordingly, the contribution of its individual components to the antioxidant, antibacterial and neuroprotective activity of the extracts is still unknown. As this plant can be available on an industrial scale, a better knowledge of its properly-relevant constituents might give access to new highly-efficient pharmaceutical substances and functional products. Therefore, herein we comprehensively characterize the secondary metabolome of G. rivale by ESI-HR-MS, ESI-HR-MSⁿ and NMR spectroscopy with a special emphasis on the polyphenolic composition of its aerial parts. Furthermore, a multilateral evaluation of the antioxidant, neuroprotective and antibacterial properties of the aqueous and ethyl acetate fractions of the total aqueous alcoholic extract as well as individual isolated polyphenols was accomplished. Altogether four phenolic acid derivatives (trigalloyl hexose, caffeoyl-hexoside malate, ellagic acid and ellagic acid pentoside), six flavonoids (three quercetin derivatives, kaempferol and three its derivatives and two isorhamnetin derivatives) and four tannins (HHDP-hexoside, proantocyanidin dimer, pedunculagin I and galloyl-bis-HHDP-hexose) were identified in this plant for the first time. The obtained aqueous and ethyl acetate fractions of the total extract as well as the isolated individual compounds showed pronounced antioxidant activity. In addition, a pronounced antibacterial activity against several strains was proved for the studied fractions (for ethyl acetate fraction the highest activity against E. coli АТСС 25922 and S. aureus strains ATCC 27853 and SG-511 (MIC 15.6 μg/mL) was observed; for aqueous fraction—against Staphylococcus aureus SG-511 (MIC 31.2 μg/mL)). However, the anti-neurodegenerative (neuroprotective) properties could not be found with the employed methods. However, the antibacterial activity of the fractions could not be associated with any of the isolated individual major phenolics (excepting 3-O-methylellagic acid). Thus, the aerial parts of water avens represent a promising source of polyphenolic compounds with antioxidant activity and therefrom derived human health benefits, although the single constituents isolated so far lack a dominant selectively bioactive constituent in the bioassays performed.

Противомикробная активность соединений полифенольной природы

Flavonoid aglycones are secondary plant metabolites that exhibit a broad spectrum of pharmacological activities, including anti-inflammatory, antioxidant, anticancer, and antiplatelet effects. However, the precise molecular mechanisms underlying their inhibitory effect on platelet activation remain poorly understood. In this study, we applied flow cytometry to analyze the effects of six flavonoid aglycones (luteolin, myricetin, quercetin, eriodictyol, kaempferol, and apigenin) on platelet activation, phosphatidylserine externalization, formation of reactive oxygen species, and intracellular esterase activity. We found that these compounds significantly inhibit thrombin-induced platelet activation and decrease formation of reactive oxygen species in activated platelets. The tested aglycones did not affect platelet viability, apoptosis induction, or procoagulant platelet formation. Notably, luteolin, myricetin, quercetin, and apigenin increased thrombin-induced thromboxane synthase activity, which was analyzed by a spectrofluorimetric method. Our results obtained from Western blot analysis and liquid chromatography–tandem mass spectrometry demonstrated that the antiplatelet properties of the studied phytochemicals are mediated by activation of cyclic nucleotide-dependent signaling pathways. Specifically, we established by using Förster resonance energy transfer that the molecular mechanisms are, at least partly, associated with the inhibition of phosphodiesterases 2 and/or 5. These findings underscore the therapeutic potential of flavonoid aglycones for clinical application as antiplatelet agents.

Introduction.Among the different groups of drugs, diuretics are one the most popular classes that have been used for treatment of cardiovascular system and kidney diseases. At the same time, synthetic diuretics which are widely used, cause large amounts of side effects, such as violation of electrolyte, acid-base and water balances, carbohydrate and lipid metabolism. Therefore, it is important to search for individual compounds of plant origin – potential pharmaceutical substances for the treatment of urinary tract diseases. In this study individual compounds were isolated from the terrestrial parts of Ononis arvensis L. and Solidago canadensis L. The diuretic activity of the summary extracts of Ononis arvensis and Solidago canadensis has previously been proven.Aim.Method development for the isolation of individual compounds, using modern physicochemical methods of analysis, from the terrestrial parts of Ononis arvensis and Solidago canadensis and the elucidation of their structure.Materials and methods.Aerial parts of Ononis arvensis and Solidago canadensis were collected in the Saint Petersburg State Chemical-Pharmaceutical University (SPCPU) Nursery Garden of Medicinal Plants (Leningrad region, Vsevolozhsky district, Priozersk highway, 38 km) in August 2019 and identified by Dr. Goncharov Mikhail of the Saint-Petersburg chemical-pharmaceutical university, Saint-Petersburg, Russia. Fraction analysis were preformed with analytical high-performance liquid chromatography using a LC-20 Prominence (Shimadzu corp., Japan) with a SPD-M20A diode-array detector. Isolation of individual compounds was carried out by preparative high-performance liquid chromatography using a Smartline (Knauer, Germany). The structures of the isolated compounds were elucidated using 1D and 2D NMR experiments (Bruker Avance III 400 MHz) along with HR-ESI-MS (Bruker Micromass Q-TOF).Results and discussion.Using the developed methods, from the aerial part of the field restharrow (O. arvensis) we managed to isolate and characterised three individual compounds (1-3). Compounds 1 and 2 are isloflavonoids – pseudobaptigenin-7-О-ß-D-glucopyranoside and formononetin-7-О-ß-D-glucopyranoside, respectively. Compound (3) is a flavonoid – kaempferol-3-O-ß-D-glucopyranoside (astragalin). All compounds were isolated for O. arvansis for the first time. Along with this, four individual compounds (4-7) were isolated from the aerial part of the canadian goldenrod (S. canadensis), namely, quercetin-3-O-ß-D-6''-acetylglucopyranoside, isoramnetin-3-О-ß-D-rutinoside (narcissin), quercetin-3-О-rutinoside (rutin) and quercetin, respectively.Conclusion.As a result of the research, methods have been developed for the isolation of 7 individual compounds, using modern physicochemical methods of analysis, from the aerial parts of Ononis arvensis and Solidago canadensis, the structures of all the isolated compounds were elucidated. Future assessment of the isolated compounds biological activity is presumed.