Native and endemic Iranian Nepeta spp.: powerful antimicrobial agents.

Pathogenic microorganisms are more or less successfully treated by synthetic chemical compounds, whose residues often cause serious health problems. Plant specialized metabolites with antimicrobial properties have for a long time been the focus of both medicine and pharmacology. This study was conducted to evaluate the in vitro antimicrobial activity of methanol extracts of selected endemic and native Iranian Nepeta species against some of the most important pathogenic bacteria and fungi. The results indicated that N. kotschyi leaf extract was the most efficient against the tested bacteria, with Pseudomonas aeruginosa being the most sensitive and fungal species were more susceptible to the extracts than bacterial strains. Nepeta spp. extracts showed a strong antifungal activity against micromycetes, except for quite resistant Aspergillus niger. Antibacterial MIC values (mg.mL-1) ranged from 0.01 (N. kotschyi) to 0.20 (N. crassifolia), while antifungal MIC values ranged from 0.02 (N. crassifolia, N. kotschyi, N. menthoides, and N. cataria) to 0.13 (N. crassifolia and N. menthoides). When compared to positive controls, in most cases the extracts performed much better. The recorded antimicrobial activity candidates the selected 4 endemic and native Iranian Nepeta spp. as prospective and promising antimicrobial agents to be used in both pharmacology and biotechnology.

Uncovering the Interrelation between Metabolite Profiles and Bioactivity of In Vitro- and Wild-Grown Catmint (Nepeta nuda L.).

Nepeta nuda L. is a medicinal plant enriched with secondary metabolites serving to attract pollinators and deter herbivores. Phenolics and iridoids of N. nuda have been extensively investigated because of their beneficial impacts on human health. This study explores the chemical profiles of in vitro shoots and wild-grown N. nuda plants (flowers and leaves) through metabolomic analysis utilizing gas chromatography and mass spectrometry (GC-MS). Initially, we examined the differences in the volatiles' composition in in vitro-cultivated shoots comparing them with flowers and leaves from plants growing in natural environment. The characteristic iridoid 4a-α,7-ß,7a-α-nepetalactone was highly represented in shoots of in vitro plants and in flowers of plants from nature populations, whereas most of the monoterpenes were abundant in leaves of wild-grown plants. The known in vitro biological activities encompassing antioxidant, antiviral, antibacterial potentials alongside the newly assessed anti-inflammatory effects exhibited consistent associations with the total content of phenolics, reducing sugars, and the identified metabolic profiles in polar (organic acids, amino acids, alcohols, sugars, phenolics) and non-polar (fatty acids, alkanes, sterols) fractions. Phytohormonal levels were also quantified to infer the regulatory pathways governing phytochemical production. The overall dataset highlighted compounds with the potential to contribute to N. nuda bioactivity.

Solvent System-Guided Extraction of Centaurium spicatum (L.) Fritch Provides Optimized Conditions for the Biological and Chemical Characteristics of the Herbal Extracts.

Spiked centaury (Centaurium spicatum) is a well-known medicinal plant from the Mediterranean region with various bioactivities, but there are no studies addressing the use of different solvent systems to improve its pharmacological potential. Nine extraction procedures were adapted to study the effects of solvent composition on the content of bioactive compounds in C. spicatum extracts and on corresponding bioactivities. Targeted metabolomics was performed to obtain information on the chemical composition of extracts. Ethanol-water-based extraction procedures were the most efficient in isolating polyphenols, while less polar butanol extract contained the highest amount of iridoids. Antioxidant potential analysis revealed stronger activity in extracts with higher polyphenol content. Bacillus cereus and Staphylococus aureus were designated as the most sensitive bacterial strains to the activity of extracts, while among the micromycetes tested, Penicillium funiculosum was the most susceptible strain. Butanol extract showed antivirulence potential on Candida albicans morphological transition from yeast to hyphal form, and selected extracts were effective against biofilm formation in two Candida species. All the extracts tested in this study showed no cytotoxic activity to immortalize human skin keratinocyte cell line (HaCaT), whereas extracts obtained by ethanol-water extraction stand out for their potent wound healing effects. Moreover, the influence of the extraction solvent system on various bioactivities of C. spicatum is reported herein for the first time. Overall, the results presented in this study promote the use of C. spicatum as a source of natural products with potential antioxidant, wound healing, and antimicrobial applications that are potentially safe for human use.

Leaves micromorphology, chemical profile, and bioactivity of in vitro-propagated Nepeta cyrenaica (Lamiaceae).

INTRODUCTION: The endemic species Nepeta cyrenaica Quézel & Zaffran, native to northeastern Libya, is valued as an important honey-bearing plant. OBJECTIVES: This study was aimed to examine the micromorphology, phytochemistry, and bioactivity of in vitro-propagated N. cyrenaica for the first time. MATERIALS AND METHODS: The leaf indumentum was examined using light and scanning electron microscopy and further characterised for histochemistry. The chemical composition of essential oil (EO) was performed using GC-MS analysis, while dichloromethane (DCM), methanol (ME), ethanol (ET), and aqueous (AQ) extracts were analysed using qualitative and quantitative LC/MS analyses. The antioxidant activities of EO and extracts were assessed using three parallel assays, while enzyme-inhibiting effects were evaluated against four enzymes. RESULTS: The leaves bear various types of glandular trichomes, with lipophilic secretion predominating. The main EO component of EO was 1,8-cineole. A considerable number of phenolics and iridoids were tentatively identified in the ME extract. Quantitative LC/MS analysis confirmed that ferulic acid, rosmarinic acid, and epigallocatechin gallate were present in the highest amount in the extracts, in which three iridoids were also quantified. Although the ME extract contained the highest amount of polyphenolics and iridoids, the DCM extract showed the best overall biological potential. Additionally, EO exerted the strongest acetylcholinesterase and tyrosinase inhibition. CONCLUSION: This study demonstrated that the endemic N. cyrenaica can be efficiently grown under in vitro conditions, where it develops various glandular trichomes that are thought to secrete and/or accumulate bioactive compounds with valuable medicinal potential.

UHPLC-MS Phytochemical Profiling and Insight into Bioactivity of Rabelera holostea (Greater Stitchwort) Extract.

Rabelera holostea (L.) M. T. Sharples & E. A. Tripp (Greater Stitchwort), formerly known as Stellaria holostea L., is widespread in the warm temperate areas of Europe and Western Asia, the Caucasus region, as well as in some countries of North Africa. Nowadays it is considered as a weed, but earlier it was often used raw in salads or for the treatment of various inflammatory disorders. The goal of this study was to determine the constituents of the methanol extract of R. holostea aerial parts and its biological potential in terms of antioxidant, antimicrobial, and anti-inflammatory properties. Until now, the constituents and biological activities of this plant were not reported in detail. A comprehensive phytochemical profiling of the extract has shown that phenolic acids, such as ferulic, chlorogenic, and p-coumaric acid, flavonoids and flavonoid glucosides, such as chrysoeriol, rutin, and naringin, are the most abundant compounds. The antioxidant activity of R. holostea extract towards DPPH and ABTS radicals, but also the total antioxidant capacity and the inhibition of lipid peroxidation were moderate. The antimicrobial potential was pronounced mostly towards some fungi such as F. oxysporum (MIC 1.25 mg/mL), whereas the capacity of R. holostea to affect the growth of bacteria was much less pronounced. R. holostea extract was most inclined to anti-inflammatory activity. At a concentration of 50 µg/mL, it significantly inhibited both cyclooxygenase enzymes (COX-1 and COX-2) by 71.24% and 72.83%, respectively. Molecular docking studies indicated that chlorogenic acid and chrysoeriol are the main contributors to COX-1 and COX-2 inhibitory activity.

Catmint (Nepeta nuda L.) Phylogenetics and Metabolic Responses in Variable Growth Conditions.

Nepeta nuda (catmint; Lamiaceae) is a perennial medicinal plant with a wide geographic distribution in Europe and Asia. This study first characterized the taxonomic position of N. nuda using DNA barcoding technology. Since medicinal plants are rich in secondary metabolites contributing to their adaptive immune response, we explored the N. nuda metabolic adjustment operating under variable environments. Through comparative analysis of wild-grown and in vitro cultivated plants, we assessed the change in phenolic and iridoid compounds, and the associated immune activities. The wild-grown plants from different Bulgarian locations contained variable amounts of phenolic compounds manifested by a general increase in flowers, as compared to leaves, while a strong reduction was observed in the in vitro plants. A similar trend was noted for the antioxidant and anti-herpesvirus activity of the extracts. The antimicrobial potential, however, was very similar, regardless the growth conditions. Analysis of the N. nuda extracts led to identification of 63 compounds including phenolic acids and derivatives, flavonoids, and iridoids. Quantification of the content of 21 target compounds indicated their general reduction in the extracts from in vitro plants, and only the ferulic acid (FA) was specifically increased. Cultivation of in vitro plants under different light quality and intensity indicated that these variable light conditions altered the content of bioactive compounds, such as aesculin, FA, rosmarinic acid, cirsimaritin, naringenin, rutin, isoquercetin, epideoxyloganic acid, chlorogenic acid. Thus, this study generated novel information on the regulation of N. nuda productivity using light and other cultivation conditions, which could be exploited for biotechnological purposes.

New Evidence for Artemisia absinthium L. Application in Gastrointestinal Ailments: Ethnopharmacology, Antimicrobial Capacity, Cytotoxicity, and Phenolic Profile.

Artemisia absinthium L. (Asteraceae) is traditionally used for gastrointestinal ailments and disorders linked to numerous risk factors including microbial infections. We aimed to provide contemporary evidence for its ethnopharmacological use and determine its antimicrobial capacity and mode of action, cytotoxicity, and phenolic constituents. Ethnopharmacological survey was conducted using semistructured interviews. Antimicrobial and antibiofilm capacities were determined by microdilution/crystal violet assay, respectively. Modes of action tested include estimation of exopolysaccharide production (congo red binding assay) and interference with membrane integrity (crystal violet uptake and nucleotide leakage assay). Cytotoxicity was determined using crystal violet assay. Polyphenolic profiling was done by advanced liquid chromatography/mass spectrometry (UHPLC-LTQ OrbiTrap MS). Artemisia absinthium in Serbia is traditionally used for gastrointestinal disorders, among others. Further study revealed high antifungal capacity of herb ethanolic extract towards range of Candida species (MIC 0.5-1 mg/mL) along with promising antibacterial activities (MIC 0.25-4 mg/mL). Interference with membrane integrity could be observed as a possible antimicrobial mechanism. Antibiofilm potential can be considered as high (towards C. krusei) to limited (towards P. aeruginosa) and moderate based on reduction in exopolysaccharide content. In concentrations up to 400 µg/mL, no cytotoxicity was observed towards HaCaT and HGF-1 cell lines. Polyphenolic analysis revealed twenty-one different constituents. A. absinthium usage as a gastrointestinal ailment remedy has been confirmed in vitro by its antimicrobial capacity towards microorganisms whose presence is linked to the diseases and associated complications and noncytotoxic nature of the natural product. The observed activities could be attributed to the present phenolic compounds.

Comparative Metabolite and Gene Expression Analyses in Combination With Gene Characterization Revealed the Patterns of Flavonoid Accumulation During Cistus creticus subsp. creticus Fruit Development.

Cistus creticus L. subsp. creticus (rockrose) is a shrub widespread in Greece and the Mediterranean basin and has been used in traditional medicine as herb tea for colds, for healing and digestive hitches, for the treatment of maladies, as perfumes, and for other purposes. Compounds from its flavonoid fraction have recently drawn attention due to antiviral action against influenza virus and HIV. Although several bioactive metabolites belonging to this group have been chemically characterized in the leaves, the genes involved in their biosynthesis in Cistus remain largely unknown. Flavonoid metabolism during C. creticus fruit development was studied by adopting comparative metabolomic and transcriptomic approaches. The present study highlights the fruit of C. creticus subsp. creticus as a rich source of flavonols, flavan-3-ols, and proanthocyanidins, all of which displayed a decreasing trend during fruit development. The majority of proanthocyanidins recorded in Cistus fruit are B-type procyanidins and prodelphinidins, while gallocatechin and catechin are the dominant flavan-3-ols. The expression patterns of biosynthetic genes and transcription factors were analyzed in flowers and throughout three fruit development stages. Flavonoid biosynthetic genes were developmentally regulated, showing a decrease in transcript levels during fruit maturation. A high degree of positive correlations between the content of targeted metabolites and the expression of biosynthetic genes indicated the transcriptional regulation of flavonoid biosynthesis during C. creticus fruit development. This is further supported by the high degree of significant positive correlations between the expression of biosynthetic genes and transcription factors. The results suggest that leucoanthocyanidin reductase predominates the biosynthetic pathway in the control of flavan-3-ol formation, which results in catechin and gallocatechin as two of the major building blocks for Cistus proanthocyanidins. Additionally, there is a decline in ethylene production rates during non-climacteric Cistus fruit maturation, which coincides with the downregulation of the majority of flavonoid- and ethylene-related biosynthetic genes and corresponding transcription factors as well as with the decline in flavonoid content. Finally, functional characterization of a Cistus flavonoid hydroxylase (F3'5'H) was performed for the first time.

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.

Summer savory (Satureja hortensis L.) extract: Phytochemical profile and modulation of cisplatin-induced liver, renal and testicular toxicity.

The aim of our study was to examine the potential ameliorating effect of the methanolic extract of Satureja hortensis L. (summer savory) aerial parts against cisplatin-induced oxidative damage in renal, hepatic, and testicular tissues. S. hortensis methanol extract at the doses of 50, 100 and 200 mg/kg of body weight were orally administered to Wistar rats once daily for 10 days. Toxicity was induced by intraperitoneal injection of a single dose of cisplatin (7.5 mg/kg of body weight) on the 5th day of the experiment. Applied treatment with S. hortensis extract restored tissue morphology, ameliorated levels of serum parameters for liver, renal and testes function, tissue oxidative stress parameters, and increased Bcl-2/Bax ratio as an indicator of apoptosis in experimental animals caused by application of cisplatin. UHPLC/DAD/HESI-MS/MS analysis revealed that S. hortensis extract was rich in phenolic compounds with rosmarinic acid (24.9 mg/g) as the main compound, followed by caffeic acid (1.28 mg/g) and naringenin (1.06 mg/g). Our findings suggest that S. hortensis may be a valuable source of dietary and pharmacologically important phenolic compounds, especially rosmarinic acid, in pharmaceutical and functional food formulations in order to maintain normal health conditions or as a remedy in various diseases caused by oxidative damage.

Nepeta rtanjensis (Lamiaceae), a plant endemic to the Balkans: Phenolic composition, antioxidant activity, and in vitro antigenotoxic effects in triiodothyronine-induced DNA damage in human lymphocytes.

The success of antioxidant therapy in hyperthyroidism implies that disease is mediated by oxidative stress, which is known as one of the causing agents of ageing, degenerative diseases, and cancer. The main objective of our study was to determine possible protective effects of methanolic extract of N. rtanjensis in triiodothyronine (T3)-induced DNA breaks of human lymphocytes under in vitro conditions, based upon plant antioxidant capacity related to its phytochemical profile, mainly its polyphenolic complex. The total phenolic and flavonoid content and the antioxidant activity using in vitro 1,1-dyphenyl-2- picrylhydrazyl reagent (DPPH) was determined in methanolic extracts of plant leaves and flowers. The phenolic compound content of 62.73±1.80mg of GaA/g, exhibited solid antioxidant activity (IC50= 112.59±0.95µg/ml). The antigenotoxic activity of 0.2, 0.5 and 1.0mg/ml N. rtanjensis methanol extracts mixture with 100µM of T3 was studied in human lymphocytes in vitro using the Comet assay. It is supposed that the antigenotoxicity of N. rtanjensis methanol extracts was caused by high presence of chlorogenic acid, rosmarinic acid and rutin, all known as efficient antioxidant bioactive compounds, which were determined by ultrahigh-pressure liquid chromatograph with MS/MS Mass Spectroscopy (UHPLC/-HESI-MS / MS).

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.

Simultaneous UHPLC/DAD/(+/-)HESI-MS/MS analysis of phenolic acids and nepetalactones in methanol extracts of Nepeta species: a possible application in chemotaxonomic studies.

INTRODUCTION: Nepeta species contain a variety of secondary metabolites, including iridoid monoterpenes - nepetalactones and phenolic acids - that are considered the main bioactive constituents. This work represents the first attempt to comparatively explore variations in these two major groups of secondary metabolites within the genus. OBJECTIVE: To develop an efficient analytical methodology for simultaneous analysis of nepetalactones and phenolic acids in methanol extracts of selected Nepeta species, and to evaluate its potential application in chemotaxonomic studies. MATERIAL AND METHODS: A UHPLC combined with linear-trap quadrupole (LTQ) orbitrap MS method was used to characterise chemical diversity and complexity of phenolics among 12 selected Nepeta species. A targeted metabolomic approach using UHPLC coupled to a diode array detector (DAD) and combined with (+/-) heated electrospray ionisation (HESI) MS/MS was developed and validated for quantitative analysis of six hydroxycinnamic acid derivatives and four nepetalactones. RESULTS: Phenolic profiling provided a valuable database of bioactive compounds in the plant group studied, including phenolic acids (hydroxybenzoic and hydroxycinnamic acids) and flavonoids (flavones, flavonols and flavanones). Principal component analysis and cluster analysis suggested the applicability of 10 targeted compounds as chemomarkers for chemotaxonomic studies. Pearson's correlation analysis revealed significant positive correlations between metabolites involved in different biosynthetic pathways (phenylpropanoid or monoterpenoid). CONCLUSION: The described targeted metabolomic approach proved to be highly beneficial in designing a phytochemical overview of the genus Nepeta, and might have applications in further clarification of phylogenetic relations. Furthermore, it has the potential to be implemented in a routine quality control of plant material and herbal preparations.

Hepatoprotective effects of secoiridoid-rich extracts from Gentiana cruciata L. against carbon tetrachloride induced liver damage in rats.

The objective of this work was to investigate the effects of the methanol extracts of Gentiana cruciata L. aerial parts (GCA) and roots (GCR) against carbon tetrachloride-induced liver injury in rats. Pretreatment with GCA and GCR, containing sweroside, swertiamarin and gentiopicrin in high concentrations, dose-dependently and significantly decreased the levels of serum transaminases, alkaline phosphatase and total bilirubin, whereas an increase in the level of total protein was found compared with the CCl4-treated group. Moreover, oral administration of extracts significantly enhanced antioxidant enzyme activities (superoxide dismutase and catalase), increased the content of glutathione and decreased the content of TBARS. Microscopic evaluations of the liver revealed CCl4-induced lesions and related toxic manifestations that were minimal in the liver of rats pretreated with extracts at the dose of 400 mg per kg b.w. The results suggest that the use of G. cruciata extracts has a merit as a potent candidate in protecting the liver against chemical induced toxicity.

Centauries as underestimated food additives: antioxidant and antimicrobial potential.

Methanol extracts of aerial parts and roots of five centaury species (Centaurium erythraea, C. tenuiflorum, C. littorale ssp. uliginosum, C. pulchellum, and Schenkia spicata) were analysed for their main secondary metabolites: secoiridoid glycosides, a group of monoterpenoid compounds, and phenolics (xanthones and flavonoids), and further investigated for antioxidant capacity and antimicrobial activity. The results of ABTS, DPPH, and FRAP assays showed that above ground parts generally displayed up to 13 times higher antioxidant activity compared to roots, which should be related to higher phenolics content, especially flavonoids, in green plant organs. Secoiridoid glycosides showed no antioxidant activity. All the tested extracts demonstrated appreciative antibacterial (0.05-0.5 mg ml(-1)) and strong antifungal activity (0.1-0.6 mg ml(-1)). Our results imply that above ground parts of all centaury species studied, could be recommended for human usage as a rich source of natural antioxidants and also in food industry as strong antimicrobial agents for food preservation.

Hepatoprotective effects of Gentiana asclepiadea L. extracts against carbon tetrachloride induced liver injury in rats.

This study is an attempt to evaluate the hepatoprotective activity of Gentiana asclepiadea L. against carbon tetrachloride-induced liver injury in rats. Methanol extracts of aerial parts (GAA) and roots (GAR) of G. asclepiadea at doses of 100, 200, and 400mg/ kg b.w. were orally administered to Wistar rats once daily for 7 days before they were treated with CCl(4). The hepatoprotective activity of the extracts in this study was compared with the reference drug silymarin. In CCl(4) treated animals, GAA and GAR significantly decreased levels of serum transaminases, alkaline phosphatase and total bilirubin, and increased the level of total protein. Treatment with the extracts resulted in a significant increase in the levels of catalase, superoxide dismutase and reduced glutathione, accompanied with a marked reduction in the levels of malondialdehyde, as compared to CCl(4) treated group. The histopathological studies confirmed protective effects of extracts against CCl(4)-induced liver injuries. No genotoxicity was observed in liver cells after GAA treatment, while GAR showed only slight genotoxic effects by comet assay. Phytochemical analysis revealed the presence of sweroside, swertiamarin and gentiopicrin in high concentrations in both extracts. It could be concluded that the use of G. asclepiadea extracts in the treatment of chemical-induced hepatotoxicity.

Antibacterial and antifungal screening of Centaurium pulchellum crude extracts and main secoiridoid compounds.

The main principles of C. pulchellum (Sw.) Druce, secoiridoid glycosides, have been studied as potent bioactive compounds. Here we scored their content in extracts of ten populations of this species. Antibacterial and antifungal assays of the extracts and pure secoiridoid glycosides were performed against eight bacterial strains and five fungal species. Methanol extracts from both aerial parts and roots exhibited excellent antibacterial (0.05-0.2 mg mL(-1)) and very good antifungal (0.1-2 mg mL(-1)) activity. Pure secoiridoid glycosides isolated from these extracts demonstrated very strong antibacterial (0.01-0.04 mg mL(-1)) and especially antifungal (0.001-0.1 mg mL(-1)) activity.

Nepetalactone content in shoot cultures of three endemic Nepeta species and the evaluation of their antimicrobial activity.

Rapid micropropagation of Nepeta rtanjensis, N. sibirica and N. nervosa was performed. Qualitative and quantitative nepetalactone content in methanol extracts of in vitro grown plants was analysed by reverse-phase HPLC coupled with UV and MS detection. Only trans,cis-nepetalactone was detected in shoots of N. rtanjensis, while cis,trans-nepetalactone stereoisomer was present in N. sibirica. No nepetalactone was observed in shoots of N. nervosa. The antimicrobial activity of methanol extracts, against eight bacterial and eight fungal species, was evaluated. All the tested extracts showed significant antibacterial and strong antifungal activity. However, N. rtanjensis extract exhibited the best antimicrobial potential.