Diabetes mellitus (DM) is frequently diagnosed at a time when patients already suffer from several cardiovascular complications. Our previously published data (Molecules 201520 (11): 20538-50) on the anti-oxidative properties of Agrimonia eupatoria L. (AE) and Cynara cardunculus L. (CC) prompted us to extend the available evidence on their possible protective activities on selected DM-related parameters in a streptozotocin-induced DM rat model and in a series of in vitro experiments. Male rats were divided into four groups: control group, untreated diabetic group, AE and CC treated diabetic groups. During a five-week period, changes in blood glucose and body weight were monitored. Then, rats were sacrificed and subjected to the assessment of changes in the reactivity of aortas and measurement of butyrylcholinesterase activity. To complete the panel of experiments, α-glucosidase activity was assessed in vitro. Our results demonstrate that both tested extracts exert similar anti-diabetic activities. However, better anti-oxidant activity of the A. eupatoria extract indicates its higher clinical potential in the prevention and/or adjuvant therapy of developing cardiovascular complications related to DM and diseases associated with oxidative stress.

Protein-binding interactions are displacement reactions which have been implicated as the causative mechanisms in many drug-drug interactions. Thus, the aim of presented study was to analyse human serum albumin-binding displacement interaction between two ligands, hypoglycaemic drug gliclazide and widely distributed plant flavonoid quercetin. Fluorescence analysis was used in order to investigate the effect of substances on intrinsic fluorescence of human serum albumin (HSA) and to define binding and quenching properties of ligand-albumin complexes in binary and ternary systems, respectively. Both ligands showed the ability to bind to HSA, although to a different extent. The displacement effect of one ligand from HSA by the other one has been described on the basis of the quenching curves and binding constants comparison for the binary and ternary systems. According to the fluorescence data analysis, gliclazide presents a substance with a lower binding capacity towards HSA compared with quercetin. Results also showed that the presence of quercetin hindered the interaction between HSA and gliclazide, as the binding constant for gliclazide in the ternary system was remarkably lower compared with the binary system. This finding indicates a possibility for an increase in the non-bound fraction of gliclazide which can lead to its more significant hypoglycaemic effect. Additionally, secondary and tertiary structure conformational alterations of HSA upon binding of both ligands were investigated using synchronous fluorescence, circular dichroism and FT-IR. Experimental data were complemented with molecular docking studies. Obtained results provide beneficial information about possible interference upon simultaneous co-administration of the food/dietary supplement and drug.

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The content of phenolic compounds (total phenolic compounds, tannins, flavonoids and anthocyanidins) of three species of thyme (Thymus pulegioides, Thymus pannonicus, Thymus praecox) of different origin (Bohemian-Moravian highlands, Křivoklát and Považský Inovec) was determined using spectrophotometric methods of European Pharmacopoeia 8 th edition. Furthermore, the determination of the content of essential oil and analysis of its constituents was realised. The amount of total phenolics was determined by a spectrophotometric method using the Folin-Ciocalteu reagent. Their content ranged from 3.87 to 8.86%. The content of tannins was established on a preliminary determination of the total phenolics, followed by adsorption of tannins on hide powder. The amount of tannins in our samples varied from 1.96 to 5.65%. The content of total flavonoids was determined by a spectrophotometric method using aluminium chloride. Quantitative analysis of flavonoids has shown that content in our samples ranged from 0.59 to 1.52% expressed as luteolin-7-O-glucoside (λ = 392 nm) and from 0.41 to 1.12% expressed as rutin (λ = 420 nm). Anthocyanins represent a small amount of total polyphenol content in Thymus species. In our samples, the content of anthocyanins expressed as cyanidin-3-O-glucoside varied from 0.02 to 0.1%. The determination of essential oil was realised by method of European Pharmacopoeia 8 th edition. Its contents in our samples ranged from 0.2 to 0.75%. Gas chromatography-mass spectrometry was used for essential oil analysis. According to the presence of main monoterpene in Thymus essential oil, we can distinguish three chemotypes: thymol, carvacrol and linalool. Due to variations of chemical constituents of thyme essential oil, it was possible to observe a relationship between occurrence of certain chemotype and origin of sample. Differences in content of flavonoids have not shown a significant relationship to locality of origin.Predložená práca bola zameraná na stanovenie obsahu vybraných fenolových zlúčenín (celkové fenoly, triesloviny, flavonoidy a antokyány) troch rôznych druhov rodu Thymus (T. pulegioides, T. pannonicus, T. praecox) s rozdielnym pôvodom (Českomoravská vrchovina, Křivoklát a Považský Inovec). Na stanovenie týchto zložiek boli využité spektrofotometrické metódy Európskeho liekopisu, 8. vydanie. Zároveň bol stanovený aj obsah silice a bola vykonaná analýza jej zložiek. Obsah celkových polyfenolov bol stanovený spektrofotometrickou metódou s využitím Folin-Ciocalteovho činidla. Obsah kolísal od 3.87 % do 8,86 %. Obsah trieslovín bol realizovaný na základe predošlého stanovenia obsahu celkových fenolov, a to adsorpciou trieslovín na kožný prášok. Ich obsah sa pohyboval v rozmedzí 1,96 % do 5,65 %. Na stanovenie obsahu flavonoidov bola využitá spektrofotometrická metóda s chloridom hlinitým. Obsah flavonoidov vyjadrených ako luteolín-7-O-glukozid (λ = 392 nm) kolísal od 0,59 % do 1,52 % a obsah flavonoidov vyjadrených ako rutín (λ = 420 nm) sa pohyboval v rozmedzí od 0,41 % do 1,12 %. Antokyány zaber...