Antidiabetic effects of polyherbal mixture made of Centaurium erythraea, Cichorium intybus and Potentilla erecta.

ETHNOPHARMACOLOGICAL RELEVANCE: The polyherbal mixture made of Centaurium erythraea aerial parts and Cichorium intybus roots and Potentilla erecta rhizomes has been used for centuries to treat both the primary and secondary complications of diabetes. AIM OF THE STUDY: As a continuation of our search for the most effective herbal mixture used as an ethnopharmacological remedy for diabetes, this study aimed to compare the in vitro biological activities of this polyherbal mixture and its individual ingredients, and, most importantly, to validate the ethnopharmacological value of the herbal mixture through evaluation of its phytochemical composition, its potential in vivo toxicity and its effect on diabetes complications. MATERIALS AND METHODS: Phytochemical analysis was performed using HPLC-UV. Antioxidant activity was estimated via the DPPH test. Potential cytotoxicity/anticytotoxicity was assessed using an in vitro RBCs antihemolytic assay and an in vivo sub-chronic oral toxicity method. Antidiabetic activity was evaluated using an in vitro α-amylase inhibition assay and in vivo using a chemically induced diabetic rat model. RESULTS: The HPLC-UV analysis revealed the presence of p-hydroxybenzoic acid, p-hydroxybenzoic acid derivative, catechin, five catechin derivatives, epicatechin, isoquercetin, hyperoside, rutin, four quercetin derivatives, caffeic acid, and four caffeic acid derivatives in the polyherbal mixture decoction. Treatment with the decoction has shown no toxic effects. The antioxidant and cytoprotective activities of the polyherbal mixture were higher than the reference's ones. Its antidiabetic activity was high in both in vitro and in vivo studies. Fourteen days of treatment with the decoction (15 g/kg) completely normalized blood glucose levels of diabetic animals, while treatments with insulin and glimepiride only slightly lowered glycemic values. In addition, lipid status of treated animals as well as levels of serum AST, ALT, ALP, creatinine, urea and MDA were completely normalized. In addition, the polyherbal mixture completely restored the histopathological changes of the liver, kidneys and all four Cornu ammonis regions of the hippocampus. CONCLUSIONS: The polyherbal mixture was effective in the prevention of both primary and secondary diabetic complications such as hyperlipidemia, increased lipid peroxidation, non-alcoholic fatty liver disease, nephropathy and neurodegeneration.

Nuclear analytical techniques used to study the trace element content of Centaurium erythraea Rafn, a medicinal plant species from sites with different pollution loads in Lower Silesia (SW Poland).

Centaurium erythraea (Gentianaceae) is a medicinal plant species with therapeutic potential officially listed in the pharmacopoeias of many European, Asian and American countries. It has had many uses in natural medicine since ancient times and it is collected mostly from wild populations. The aim of this study is to investigate the trace element composition of C. erythraea using instrumental neutron activation analysis (INAA). The results of the performed investigations show that INAA has proved to be an efficient analytical technique for the determination of trace elements in medicinal plants. The studied plant contains elements important to the human diet and metabolism that are needed for growth, development and the prevention and curing of disease. A comparison with the reference levels of elements for plants shows that the concentrations of most elements in C. erythraea collected from all types of sites exceed those regarded as the reference. Compared to the values of the elements in C. erythraea from rural areas (LP), the concentrations of most of the investigated elements in C. erythraea collected from the lignite basin, urban areas and in the vicinity of the A4 highway (MP) were significantly higher. The results obtained can be used for control and monitoring in the production of pharmaceuticals based on natural medical plants.

Isolation and cytotoxic activities of undescribed iridoid and xanthone glycosides from Centaurium erythraea Rafn. (Gentianaceae).

Centaurium erythraea Rafn. (Gentianaceae) is used in internal traditional therapy as an anthelmintic, hypotensive, antipyretic, and antidiabetic. It is used externally for the treatment of wounds. Ursolic acid, maslinic acid, secologanin, secologanin dimethyl acetal, centauroside A, erythraeaxanthone I, erythraeaxanthone II, and demethyleustomin were isolated from aerial parts of Centaurium erythraea and were identified using spectroscopic methods, including NMR and mass spectrometry. The cytotoxic potency of undescribed compounds was evaluated by the XTT assay against human breast cancer MCF-7, MDA-MB-453 and mouse fibroblast 3T3-L1 cell lines. Erythraeaxanthone II was found to have the most potent cytotoxic activity.

Phytochemical and in silico studies for potential constituents from Centaurium spicatum as candidates against the SARS-CoV-2 main protease and RNA-dependent RNA polymerase.

In the present study, a new secoiridoid glycoside lisianthoside II 1, along with seven known compounds 2-8, were isolated from Centaurium spicatum L. In-silico molecular docking and molecular dynamic simulation against SARS-CoV-2 Main protease (Mpro) and RNA-dependent RNA polymerase (RdRp) were conducted. The affinity docking scores revealed that 8 is the best bound ligand to Mpro active site with binding energy of -14.9877 kcal/mol (RSMD = 1.16 Å), while 6 was the highest against RdRp (-16.9572 kcal/mol, RMSD = 1.01 Å). Moreover, the molecular dynamic simulation revealed that 8 with a (ΔG) of -7.9 kcal/mol (RMSD value of 2.6 Å) and 6 (RMSD value of 1.6 Å) and binding free energy (ΔG) of -7.1 kcal/mol achieved the highest stability over 50 ns of MDS inside the Mpro and RdRp enzyme's active site, respectively. Hence, the isolated compounds could be a good lead for development of new leads targeting COVID-19.

Phytohormone profiles in non-transformed and AtCKX transgenic centaury (Centaurium erythraea Rafn) shoots and roots in response to salinity stress in vitro.

Plant hormones regulate numerous developmental and physiological processes. Abiotic stresses considerably affect production and distribution of phytohormones as the stress signal triggers. The homeostasis of plant hormones is controlled by their de novo synthesis and catabolism. The aim of this work was to analyse the contents of total and individual groups of endogenous cytokinins (CKs) as well as indole-3-acetic acid (IAA) in AtCKX overexpressing centaury plants grown in vitro on graded NaCl concentrations (0, 50, 100, 150, 200 mM). The levels of endogenous stress hormones including abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) were also detected. The elevated contents of total CKs were found in all analysed centaury shoots. Furthermore, increased amounts of all five CK groups, as well as enhanced total CKs were revealed on graded NaCl concentrations in non-transformed and AtCKX roots. All analysed AtCKX centaury lines exhibited decreased amounts of endogenous IAA in shoots and roots. Consequently, the IAA/bioactive CK forms ratios showed a significant variation in the shoots and roots of all AtCKX lines. In shoots and roots of both non-transformed and AtCKX transgenic centaury plants, salinity was associated with an increase of ABA and JA and a decrease of SA content.

Isolation and characterization of microsatellites markers in Centaurium grandiflorum ssp. boissieri.

BACKGROUND: Estimating outcrossing/selfing rates and characterizing genetic diversity with microsatellite markers are crucial to understanding the evolution of plant mating systems. METHODS AND RESULTS: We developed, optimized and characterized eight new primer pairs for Centaurium grandiflorum ssp. boissieri and transferred them to three subspecies of Centaurium quadrifolium. Two SSR loci were transferred from Sabatia campestris to the four Centaurium taxa. Polymorphisms, He, Ho and H-W deviations were estimated in two populations of C. grandiflorum ssp. boissieri and in seven individuals each of C. quadrifolium ssp. barrelieri, C. quadrifolium ssp. parviflorum and C. quadrifolium ssp. quadrifolium. A total of 80 individuals was used in these experiments. The number of polymorphic loci varied among species from one to ten. A total of 127 alleles was scored. The average number of alleles per locus was 12.7. He was higher than Ho in all sampled populations. Hardy-Weinberg equilibrium was found for some loci in different species. CONCLUSIONS: This is the first report of microsatellites successfully amplified in the whole Centaurium genus. They will be valuable for estimating mating system parameters and genetic diversity and exploring their relationships with the wide variation in flower morphology in the genus, especially anther-stigma separation.

Phytochemical properties, biological activities and medicinal use of Centaurium erythraea Rafn.

ETHNOPHARMACOLOGICAL RELEVANCE: Centaurium erythraea is an important medicinal plant in many countries, e.g. Morocco, Algeria, Italy, Spain, Portugal, and countries of Balkan Peninsula. It is used in folk medicine to treat various illnesses. It is also used as an antiapoplectic, anticoagulant, anticholagogue, antipneumonic, hematocathartic, and as a hypotensive agent. AIM OF THE REVIEW: In this review, previous reports on the taxonomy, botanical description, geographic distribution, ethnomedicinal applications, phytochemistry, pharmacological properties, and toxicity of Centaurium erythraea were critically summarized. MATERIALS AND METHODS: Scientific search engines including PubMed, ScienceDirect, SpringerLink, Web of Science, Scopus, Wiley Online, SciFinder, and Google Scholar were consulted to collect data on C. erythraea. The data presented in this work summarized the main reports on C. erythraea phytochemical compounds, ethnomedicinal uses, and pharmacological activities. RESULTS: C. erythraea is used in traditional medicine to treat various diseases such as diabetes, fever, rhinitis, stomach ailments, urinary tract infections, dyspeptic complaints, loss of appetite, and hemorrhoids, and as diuretic. The essential oils and extracts of C. erythraea exhibited numerous biological properties such as antibacterial, antioxidant, antifungal, antileishmanial, anticancer, antidiabetic, anti-inflammatory, insecticidal, diuretic, gastroprotective, hepatoprotective, dermatoprotective, neuroprotective, and inhibitory agent for larval development. Phytochemical characterization of C. erythraea revealed the presence of several classes of secondary metabolites such as xanthonoids, terpenoids, flavonoids, phenolic acids, and fatty acids. CONCLUSIONS: Ethnomedicinal studies demonstrated the use of C. erythraea for the treatment of various disorders. Pharmacological reports showed that C. erythraea especially its aerial parts and roots exhibited potent, and beneficial activities. These findings confirmed the link between the traditional medicinal use and the results of the scientific biological experiments. Considering these results, further investigation using diverse in vivo pharmacological assays are strongly recommended to validate the results of its traditional use. Toxicological tests and pharmacokinetic studies are also required to validate the safety and efficacy of C. erythraea and its bioactive contents.

Changes in beneficial bioactive compounds in eight traditional herbal liqueurs during a one-month maceration process.

BACKGROUND: Herbs are rich in various beneficial bioactive compounds and they can be used for many different purposes. One of the most common is maceration of herbs in alcohol. Different substances respond differently to extraction in prepared solutions. It is very important to enhance the highest proportion of beneficial ingredients during the maceration process in a herbal liqueur. A comparative analysis of numerous different phenolic compounds from eight of the most frequently used herbs for making aperitifs in Europe was performed. RESULTS: In the comparison among all studied herbs, the highest phenolic content was found with Artemisia absinthium (wormwood) (14.61 mg g-1 ) and Mentha piperita (peppermint) (13.89 mg g-1 ), while the lowest content was found with Centaurium erythraea (common centaury) (3.96 mg g-1 ). Salvianolic acid isomers and caffeic acid derivatives were the greatest contributors to the total phenolic content in lemon balm, wormwood, peppermint, fennel and sage. These compounds contain more hydroxyl groups and they were better extracted at the beginning of the maceration process. Caraway and common centaury contain more flavonols (quercetin and kaempferol derivatives), with higher chemical stability and fewer hydroxyl groups in their structure. CONCLUSION: The compositions of eight herbal liqueurs were highly related to the presence of different herbal ingredients and their solubility in the extract over time. Most flavonol derivatives were extracted over a longer time and the two liqueurs (common centaury and caraway) therefore had the highest phenolic contents after 3 weeks of maceration. © 2019 Society of Chemical Industry.

Centaurium Erythraea Extracts Exert Vascular Effects through Endothelium- and Fibroblast-dependent Pathways.

Centaurium erythraea is a plant used in traditional medicine for several cardiovascular disorders, namely hypertension, but there is no scientific evidence able to provide a molecular basis for its claimed antihypertensive effects. After a preliminary screen of extracts obtained from sequential extraction of C. erythraea aerial parts, effects of the methanolic fraction (MFCE) on changes in perfusion pressure of isolated rat mesenteric vascular bed (MVB) and in rat cardiac fibroblasts proliferation were investigated, gathering information on the mechanisms involved in endothelium-dependent effects and their dependence on a pro-proliferative stimulus. The HPLC-DAD determination of the phenolics content of MFCE revealed the presence of 22 phenolic compounds. MFCE reduced (63.3 ± 3.9%; n = 4) perfusion pressure in MVB and almost completely abrogated the Ang II-induced increase in cardiac fibroblasts proliferation. Reduction of the perfusion pressure caused by MFCE was endothelium-dependent and occurred in parallel with an increase in NO release. These effects were inhibited by muscarinic receptor antagonists, by L-NAME (a NO synthase inhibitor), and by ODQ (a soluble guanylate cyclase inhibitor). Experiments revealed that effects required the involvement of K+ channels, being inhibited by tetraethylamonium (TEA; a Ca2+ activated K+ channels inhibitor) and by glibenclamide (an ATP-sensitive K+ channels inhibitor). In conclusion, extracts from C. erythraea, particularly the compounds present in the MFCE, induce endothelium-dependent vasodilation and prevent fibroblast proliferation induced by angiotensin II, which can account for the claimed antihypertensive effects of C. erythraea in traditional medicine.

Bioactivities of Centaurium erythraea (Gentianaceae) Decoctions: Antioxidant Activity, Enzyme Inhibition and Docking Studies.

Centaurium erythraea is recommended for the treatment of gastrointestinal disorders and to reduce hypercholesterolemia in ethno-medicinal practice. To perform a top-down study that could give some insight into the molecular basis of these bioactivities, decoctions from C. erythraea leaves were prepared and the compounds were identified by liquid chromatography-high resolution tandem mass spectrometry (LC-MS/MS). Secoiridoids glycosides, like gentiopicroside and sweroside, and several xanthones, such as di-hydroxy-dimethoxyxanthone, were identified. Following some of the bioactivities previously ascribed to C. erythraea, we have studied its antioxidant capacity and the ability to inhibit acetylcholinesterase (AChE) and 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR). Significant antioxidant activities were observed, following three assays: free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction; lipoperoxidation; and NO radical scavenging capacity. The AChE and HMGR inhibitory activities for the decoction were also measured (56% at 500 µg/mL and 48% at 10 µg/mL, respectively). Molecular docking studies indicated that xanthones are better AChE inhibitors than gentiopicroside, while this compound exhibits a better shape complementarity with the HMGR active site than xanthones. To the extent of our knowledge, this is the first report on AChE and HMGR activities by C. erythraea decoctions, in a top-down analysis, complemented with in silico molecular docking, which aims to understand, at the molecular level, some of the biological effects ascribed to infusions from this plant.

Centaurium erythraea extract improves survival and functionality of pancreatic beta-cells in diabetes through multiple routes of action.

ETHNOPHARMACOLOGICAL RELEVANCE: Centaurium erythraea Rafn (CE) is used as a traditional medicinal plant in Serbia to treat different ailments due to its antidiabetic, antipyretic, antiflatulent and detoxification effects. AIM OF THE STUDY: Elucidation of the mechanisms that underlie the antioxidant and pro-survival effects of the CE extract (CEE) in beta-cells and pancreatic islets from streptozotocin (STZ)-treated diabetic rats. MATERIAL AND METHODS: Diabetes was induced in rats by multiple applications of low doses of STZ (40 mg/kg intraperitoneally (i.p.), for five consecutive days). CEE (100 mg/kg) was administered orally, in the pre-treated group for two weeks before diabetes induction, during the treatments with STZ and for four weeks after diabetes onset, and in the post-treatment group for four weeks after diabetes induction. The impact of CEE on diabetic islets was estimated by histological and immunohistochemical examination of the pancreas. Molecular mechanisms of the effects of CEE were also analyzed in insulinoma Rin-5F cells treated with STZ (12 mM) and CEE (0.25 mg/mL). Oxidative stress was evaluated by assessing the levels of DNA damage, lipid peroxidation, protein S-glutathionylation and enzymatic activities and expression of CAT, MnSOD, CuZnSOD, GPx and GR in beta-cells. The presence and activities of the redox-sensitive and islet-enriched regulatory proteins were also analyzed. RESULTS: Treatment with CEE ameliorated the insulin level and glycemic control in STZ-induced diabetic rats by improving the structural and functional properties of pancreatic islets through multiple routes of action. The disturbance of islet morphology and islet cell contents in diabetes was reduced by the CEE treatment and was associated with a protective effect of CEE on the levels of insulin, GLUT-2 and p-Akt in diabetic islets. The antioxidant effect of CEE on STZ-treated beta-cells was displayed as reduced DNA damage, lipid peroxidation, protein S-glutathionylation and alleviation of STZ-induced disruption in MnSOD, CuZnSOD and CAT enzyme activities. The oxidative stress-induced disturbance of the transcriptional regulation of CAT, MnSOD, CuZnSOD, GPx and GR enzymes in beta-cells was improved after the CEE treatment, and was observed as readjustment of the presence and activities of redox-sensitive NFκB-p65, FOXO3A, Sp1 and Nrf-2 transcription factors. The observed CEE-mediated induction of proliferative and pro-survival pathways and insulin expression/secretion after STZ-induced oxidative stress in beta-cells could be partially attributed to a fine-tuned modulation of the activities of pro-survival Akt, ERK and p38 kinases and islet-enriched Pdx-1 and MafA regulatory factors. CONCLUSIONS: The results of this study provide evidence that CEE improves the structural and functional properties of pancreatic beta-cells by correcting the endogenous antioxidant regulatory mechanisms and by promoting proliferative and pro-survival pathways in beta-cells.

HPLC-DAD-ESI/MSn phenolic profile and in vitro biological potential of Centaurium erythraea Rafn aqueous extract.

Centaurium erythraea Rafn is a food flavouring used in both food and beverage industries. Despite the existence of some works on this species, only few focus their attention on its common form of consumption (infusion). Thus, we intended to explore the chemical composition and the biological properties of infusions from C. erythraea aerial parts. Phenolic compounds were identified by HPLC-DAD-ESI/MSn, twenty-two flavonoid derivatives being reported for the first time. Concerning to the biological potential, the best scavenging activity was observed for the superoxide anion radical. Moreover, this extract revealed to have some effect on the inhibition of 5-lipoxygenase, no cytotoxicity against RAW 264.7 macrophage cells line, and a weak potential to decrease the nitric oxide levels in this cell system. The results suggest that C. erythraea aerial parts could be valuable sources of health benefits compounds, contributing to its valorisation and its further application in functional foods.

Organ-specific and genotype-dependent constitutive biosynthesis of secoiridoid glucosides in Centaurium erythraea Rafn, and its elicitation with methyl jasmonate.

While bioactive properties of Centaurium erythraea Rafn secoiridoid glucosides (SG) are widely recognized, many aspects related to their biochemistry, metabolism and relationship to the overall plant physiology are not yet understood. Here we present for the first time an insight into the molecular background of organ-specific and genotype-dependent constitutive biosynthesis of secoiridoids in C. erythraea, by comparing chemical profiles and secoiridoid glucosides-related gene expression. Genes encoding enzymes for intermediate steps of secoiridoids biosynthesis up to secologanin have been identified by analysing transcriptomic data from C. erythraea leaves. Results suggest an organ-specific capacity for the production and accumulation of secoiridoid glucosides, and highlight leaves as the main biosynthesis site. They also point out that significant differences in SG content among various C. erythraea genotypes, are, at least partially, determined by different expression patterns of SG-related genes. The biosynthesis of SG in C. erythraea leaves is enhanced upon treatments with methyl jasmonate (MeJA), which causes reprogramming of SG-related gene expression, leading to an increased production of valuable bioactive compounds. The present study unveiled several rate-limiting genes (encoding GES, G8O, 8HGO, IS and 7DLGT) in SG biosynthesis. SLS and CPR are highlighted as important genes/enzymes that might regulate biosynthetic flux through SG pathway. Information gathered within this study will help us gain deeper insight into the SG metabolism and develop strategies for enhanced biosynthesis of specific secoiridoid glucosides in homologous or heterologous systems.

Off-line coupling of new generation centrifugal partition chromatography device with preparative high pressure liquid chromatography-mass spectrometry triggering fraction collection applied to the recovery of secoiridoid glycosides from Centaurium erythraea Rafn. (Gentianaceae).

A purification sequence including a Gilson CPC 250 PRO device coupled to PrepHPLC hyphenated with a MS triggering fraction collector was applied to isolate secoiridoid glycosides from a complex methanolic extract of Centaurium erythraea. This species is widely used for ethnomedicinal purposes around the Mediterranean Sea. The solvent system ethyle acetate/ethanol/water 7.5/3/5 was determined using shake-flask method targeting swertiamarin, the major secoiridoid of the extract. Optimization of CPC experimental parameters enabled the injection of 4g of extract with a flow rate of 40mL/min at 3000rpm to provide a secoiridoid glycosides enriched fraction. 130mg of this latter was submitted to a second step of purification by preparative HPLC (gradient water/formic acid (19:1) (A) and methanol (B) as follows: 0min, 85% A; 8min, 60% A; 12min, 55% A; 35min, 55% A; 40min, 10% A; 50min, 10% A; 52min, 85% A; 55min, 85% A) to give swertiamarin (36mg, yield 27.7%, purity 98.2%). Other secoiridoid glycosides (sweroside, gentiopicroside, secologanol, secoxyloganin) were also isolated in minor amounts. As these monoterpene derivatives are responsible for several biological activities, their quick recovery with high yield and purity may serve as a model for further scale-up and industrial development.

Centaura menor (Centaurium erythraea Rafn) / Centáurea (Centaurium erythraea Rafn) / Minor centaury, Centaurium erythraea

La centaura menor es una planta medicinal de uso tradicional en Europa empleada principalmente en ámbito digestivo debido a sus características amargo-eupépticas, posicionándose en este aspecto a la altura de la genciana (Gentiana lutea L.) o a las "nencias" de Sudamérica (Gentianella sp.). Más allá de este encasillamiento digestivo, la planta ha sido vastamente estudiada enlos últimos diez años, habiéndose descrito propiedades hipoglucemiantes, antimicrobianas y antiinflamatorias (AU)

A centáurea menor é uma planta medicinal usada tradicionalmente na Europa, principalmente para problemas na área digestiva devido às suas características amargo-eupépticas, posicionando-se a este respeito ao nível da genciana (Gentiana lutea L.) ou "nencias" da América do Sul (Gentianella sp.). Para além deste uso a nível digestivo, a planta tem sido amplamente estudada nos últimos dez anos, tendo-se descrito propriedades hipoglicemiantes, antimicrobianas e anti-inflamatórias (AU)

Centaury is a medicinal plant with traditional use in Europe, being used mainly in the digestive area, by his bittereupeptic characteristics, positioning itself in this regard, at the same efficacy of gentian (Gentiana lutea L.), or the "nencias" from South America (Gentianella sp.). Beyond this digestive typecasting, the herb has been vastly studied in the last ten years, and important properties being found, like hypoglycaemic, antimicrobial and antiinflammatory (AU)

Chemodiversity of two closely related tetraploid Centaurium species and their hexaploid hybrid: Metabolomic search for high-resolution taxonomic classifiers.

Species within the genus Centaurium readily hybridize and polyploid complexes are often seen in natural populations. We describe phytochemical profiles of newly discovered allohexaploid hybrid, here named Centaurium pannonicum, and its parental tetraploid species C. erythraea and rare C. littorale ssp. compressum. Our aim was to examine chemodiversity of these taxa in the area of Vojvodina (North Serbia) and to perform metabolomics search for chemical classifiers which would provide high resolution discrimination of parental and hybrid individuals. In sum, UHPLC-MS/MS Orbitrap metabolomics fingerprinting revealed seventy compounds in methanol extracts. Despite the lack of qualitative chemical novelty in hybrid plants, UHPLC-qqqMS targeted metabolomics approach, aimed at three secoiridoid compounds and seventeen phenolics, pointed to considerable differences in quantitative composition of these dominant compounds among the plant taxa studied. In addition to the difference in the ploidy levels, the hybrid taxon was well distinguished from both parental species based on metabolite profiles, and, for most individuals, positioned intermediately to the parental taxa in both PCA and hierarchical clustering. After optimizing and comparing several statistical learning methods, it was possible to narrow the number of taxonomic classifiers to five (three xanthones, one secoiridoid glycoside, and one phenolic acid), while increasing the differentiation resolution. The presented metabolomics approach will certainly, along with morphometrics and molecular genetics studies, have high impact on further elucidation of complex relationships among taxa within the genus Centaurium.

Geographic variation in floral traits and the capacity of autonomous selfing across allopatric and sympatric populations of two closely related Centaurium species.

Floral traits and the relative contribution of autonomous selfing to total seed set varies geographically and is often driven by the availability and abundance of suitable pollinators and/or the presence of co-flowering relatives. In the latter case, competition for pollinator services and costs of hybridization can select for floral traits that reduce interspecific gene flow and contribute to prezygotic isolation, potentially leading to geographic variation in floral divergence between allopatric and sympatric populations. In this study, we investigated variation in floral traits and its implications on the capacity of autonomous selfing in both allopatric and sympatric populations of two closely related Centaurium species(Gentianaceae) across two distinct geographic regions(UK and mainland Europe). Although the magnitude and direction of floral differentiation varied between regions, sympatric populations were always significantly more divergent in floral traits and the capacity to self autonomously than allopatric populations. These results indicate that mating systems can vary substantially within a species and that the joint occurrence of plant species can have a major impact on floral morphology and capacity of autonomous selfing, most likely as a way to reduce the probability of interspecific interference.

Centaurium erythraea methanol extract protects red blood cells from oxidative damage in streptozotocin-induced diabetic rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Centaurium erythraea Rafn (CE) is a traditional medicinal herb in Serbia with antidiabetic, digestive, antipyretic and antiflatulent effects AIM OF THE STUDY: To investigate the potential protective effects of the methanol extract of the aerial parts of CE against glyco-oxidative stress in red blood cells (RBCs) in rats with experimentally induced diabetes. MATERIAL AND METHODS: Diabetes was induced in Wistar rats by intraperitoneal (i.p.) injection of multiple low-dose streptozotocin (STZ) (40mg/kg, for five consecutive days), with the 1st day after the last STZ injection taken as the day of diabetes onset. The methanol extract of CE (100mg/kg) was administered orally and daily, two weeks before the first STZ injection, during the 5-day treatment with STZ, and for four weeks after the STZ injections (pre-treated group) or for four weeks after diabetes onset (post-treated group). The effect of CE extract administration on the redox status of RBCs was evaluated by assessing lipid peroxidation, the ratio of reduced/oxidized glutathione (GSH/GSSG), the level of S-glutathionylated proteins (GSSP) and the enzymatic activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) in RBCs four weeks after diabetes onset. The major biochemical parameters of diabetes, protein glycation/glycosylation of erythrocytes and parameters which correlate with their aggregation and deformability were also evaluated. RESULTS: Daily application of CE extract to STZ-induced diabetic rats provided important antidiabetic effects, observed in both pre-treated and post-treated groups of diabetic rats as elevated serum insulin concentration, reduction of blood glucose and glycated hemoglobin concentrations and an improved lipid profile. Antioxidant effects of CE extract were detected in RBCs of diabetic rats and observed as decreased lipid peroxidation and ameliorated oxidative damage as a result of increased SOD, CAT and GR activities, an improved GSH/GSSG ratio and reduced GSSP levels. Moreover, the CE extract protected RBC proteins from hyperglycemia-induced damage by reducing non-enzymatic glycation and enzymatic glycosylation processes. CE extract was more effective when applied before diabetes induction (pre-treated group). CONCLUSIONS: The results of this study show that the Centaurium erythraea methanol extract protects RBCs in diabetic animals from oxidative damage. They provide additional support for the application of this traditionally used plant in diabetes management.

Nonprenylated Xanthones from Gentiana lutea, Frasera caroliniensis, and Centaurium erythraea as Novel Inhibitors of Vascular Smooth Muscle Cell Proliferation.

Aberrant proliferation of vascular smooth muscle cells (VSMC) plays a major role in restenosis, the pathological renarrowing of the blood vessel lumen after surgical treatment of stenosis. Since available anti-proliferative pharmaceuticals produce unfavorable side effects, there is high demand for the identification of novel VSMC proliferation inhibitors. A natural product screening approach using a resazurin conversion assay enabled the identification of gentisin (1) from Gentiana lutea as a novel inhibitor of VSMC proliferation with an IC50 value of 7.84 µM. Aiming to identify further anti-proliferative compounds, 13 additional nonprenylated xanthones, isolated from different plant species, were also tested. While some compounds showed no or moderate activity at 30 µM, 1-hydroxy-2,3,4,5-tetramethoxyxanthone (4), swerchirin (6), and methylswertianin (7) showed IC50 values between 10.2 and 12.5 µM. The anti-proliferative effect of 1, 4, 6, and 7 was confirmed by the quantification of DNA synthesis (BrdU incorporation) in VSMC. Cell death quantification (determined by LDH release in the culture medium) revealed that the compounds are not cytotoxic in the investigated concentration range. In conclusion, nonprenylated xanthones are identified as novel, non-toxic VSMC proliferation inhibitors, which might contribute to the development of new therapeutic applications to combat restenosis.

Polybrominated diphenyl ethers (PBDEs) in herbaceous Centaurium erythraea affected by various sources of environmental pollution.

Polybrominated diphenyl ethers (PBDEs) are persistent xenobiotics with harmful effects on humans and wildlife. Their levels in the environment and accumulation in biota must be carefully controlled especially in species harvested from wild populations and commonly used as medicines. Our objective has been to determine PBDE concentrations (BDEs 28, 47, 66, 85, 99, 100, 153, 154, 183 and 209) in Centaurium erythraea collected at sites with various levels of environmental pollution. PBDE congener profiles in C. erythraea were dominated by BDE209, which accounted for 47-89% of the total PBDE burden in the plants. Principal Component and Classification Analysis, which classifies the concentration of PBDEs in C. erythraea, allowed us to distinguish the pattern of these compounds characteristic for the origin of pollution: BDEs 28, 47, 66, 85, 99, 100 for lignite and general chemical industry and the vicinity of an expressway and BDEs 183 and 209 for a thermal power plant and ferrochrome smelting industry. Careful selection of sites with C. erythraea for medicinal purposes is necessary as this herb can accumulate PBDEs while growing at polluted sites.