Chemical Analysis and in Vitro Antiviral Effects of Northeast Türkiye Propolis Samples against HSV-1.

Propolis is one of the mixtures with the widest biological activity among natural products used in complementary medicine. HSV-1 is a highly contagious and endemic virus. Available drugs are insufficient for recurrent HSV-1 infections. Therefore, new approaches to treat HSV-1 infections are still being developed. In this study, it was aimed to investigate the inhibition effect of ethanolic Anatolian propolis extracts obtained from the Eastern Black Sea Region (Pazar, Ardahan, and Uzungöl) on HSV-1. In addition to the total phenolic (TPC) and the total flavonoid content (TFC), the phenolic profiles of the extracts were analyzed by HPLC-UV. The antiviral activity of the extracts were tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), quantitative Real Time Polymerase Chain Reaction (qRT-PCR), and plaque reduction tests, and the results were evaluated statistically. It was determined that the total amount of phenolic substances varied between 44.12 and 166.91 mg GAE/g, and the total flavonoid content of the samples varied between 12.50 and 41.58 (mg QUE/g). It was shown that all propolis samples used in the current study were effective against HSV-1, but the higher phenolic compounds contained in the samples showed the higher activity. The results show that ethanolic propolis extracts are promising candidates for HSV-1 treatment.

Comparison of Protective Effect of Aqueous and Ethanolic Extracts of Propolis against Gastric Ulceration in Rats.

This study focused on the protective effects of different types of propolis extracts on gastric mucosa in indomethacin-induced rats. The animals were divided into nine groups: control, negative control (ulcer), positive control (omeprazole), and experimental groups, which were summarized by 200, 400, and 600 mg/kg, bw for aqueous-based and ethanol, respectively. According to the histopathological evaluation, more than others, the doses of 200 and 400 mg/kg of aqueous-based propolis extracts had different degrees of positive effects on the gastric mucosa. Generally, the biochemical analyses of the gastric tissue showed a correlation with microscopic evaluations. According to the phenolic profile analysis, while pinocembrin (684.34±1.70 µg/ml) and chrysin (540.54±9.06 µg/ml) were the most abundant phenolics in the ethanolic extract, ferulic acid (53.77±0.07 µg/ml) and p-coumaric acid (52.61±0.42 µg/ml) dominated the aqueous-based extract. Also, the total phenolic content (TPC), total flavonoid content (TFC), and DPPH radical scavenging activity of the ethanolic extract showed almost nine-fold superiority compared to the aqueous-based extracts. Based on data from preclinical data, it was decided that the best doses for the main goal of the study were 200 mg and 400 mg/kg, bw for aqueous-based propolis extract.

A comparative study of antimicrobial, anti-quorum sensing, anti-biofilm, anti-swarming, and antioxidant activities in flower extracts of pecan (Carya illinoinensis) and chestnut (Castanea sativa).

Antibiotic resistance, which has increased rapidly in recent years because of uncontrolled and unconscious antibiotic consumption, poses a major threat to public health. The inadequacy of existing antibiotics has increased the need for new, effective, and less toxic antibiotic raw materials or antibiotic derivatives. Pecan (Carya illinoinensis) and Chestnut (Castanea sativa) flowers possess abundant pollen contents and exhibit similar morphological features. The purpose of this study was to compare these two flower extracts in terms of their antimicrobial and antioxidant activities. Total phenolic content, total flavonoid contents, and phenolic components were also analyzed in aquatic and ethanolic extracts. Antioxidant activities were measured using ferric reducing/antioxidant capacity (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. Antimicrobial and antifungal activities were compared by means of agar diffusion tests against bacteria including Staphylococcus aureus, Bacillus cereus, Mycobacterium smegmatis, Acinetobacter haemolyticus, and Chromobacterium violaceum, and the yeasts Candida albicans and Candida parapsilosis. Anti-quorum sensing (anti-QS), anti-biofilm, and anti-swarming (SW) activities were also studied against Chromobacterium violaceum ATCC 31532, Chromobacterium violaceum ATCC 12472, and Pseudomonas aeruginosa PA01, respectively. Both extracts were rich in ellagic acid and gallic acid and exhibited similar antioxidant properties. Both flower extracts exhibited high antimicrobial and antifungal activities as well as anti-biofilm, anti-QS, and anti-SW activities.

Targeting CoV-2 spike RBD and ACE-2 interaction with flavonoids of Anatolian propolis by in silico and in vitro studies in terms of possible COVID-19 therapeutics.

Propolis is a multi-functional bee product rich in polyphenols. In this study, the inhibitory effect of Anatolian propolis against SARS-coronavirus-2 (SARS-CoV-2) was investigated in vitro and in silico. Raw and commercial propolis samples were used, and both samples were found to be rich in caffeic acid, p-coumaric acid, ferulic acid, t-cinnamic acid, hesperetin, chrysin, pinocembrin, and caffeic acid phenethyl ester (CAPE) at HPLC-UV analysis. Ethanolic propolis extracts (EPE) were used in the ELISA screening test against the spike S1 protein (SARS-CoV-2): ACE-2 interaction for in vitro study. The binding energy values of these polyphenols to the SARS-CoV-2 spike and ACE-2 protein were calculated separately with a molecular docking study using the AutoDock 4.2.6 program. In addition, the pharmacokinetics and drug-likeness properties of these eight polyphenols were calculated according to the SwissADME tool. The binding energy value of pinocembrin was highest in both receptors, followed by chrysin, CAPE, and hesperetin. Based on the in silico modeling and ADME (absorption, distribution, metabolism, and excretion) behaviors of the eight polyphenols, the compounds exhibited the potential ability to act effectively as novel drugs. The findings of both studies showed that propolis has a high inhibitory potential against the Covid-19 virus. However, further studies are now needed.

Investigation of potential inhibitor properties of ethanolic propolis extracts against ACE-II receptors for COVID-19 treatment by molecular docking study.

The angiotensin-converting enzyme (ACE)-related carboxypeptidase, ACE-II, is a type I integral membrane protein of 805 amino acids that contains 1 HEXXH-E zinc binding consensus sequence. ACE-II has been implicated in the regulation of heart function and also as a functional receptor for the coronavirus that causes the severe acute respiratory syndrome (SARS). In this study, the potential of some flavonoids presents in propolis to bind to ACE-II receptors was calculated with in silico. Binding constants of ten flavonoids, caffeic acid, caffeic acid phenethyl ester, chrysin, galangin, myricetin, rutin, hesperetin, pinocembrin, luteolin and quercetin were measured using the AutoDock 4.2 molecular docking program. And also, these binding constants were compared to reference ligand of MLN-4760. The results are shown that rutin has the best inhibition potentials among the studied molecules with high binding energy - 8.04 kcal/mol, and it is followed by myricetin, quercetin, caffeic acid phenethyl ester and hesperetin. However, the reference molecule has binding energy of - 7.24 kcal/mol. In conclusion, the high potential of flavonoids in ethanolic propolis extracts to bind to ACE-II receptors indicates that this natural bee product has high potential for COVID-19 treatment, but this needs to be supported by experimental studies.

Distinct Epigenetic Reprogramming, Mitochondrial Patterns, Cellular Morphology, and Cytotoxicity after Bee Venom Treatment.

BACKGROUND: Bee venom is a promising agent for cancer treatment due to its selective cytotoxic potential for cancer cells through apoptotic pathways. However, there is no evidence for changes in the epigenome and mitochondrial DNA copy numbers after bee venom application. The purpose of this study was to determine the impact of bee venom on cytosine modifications and mitochondrial DNA copy number variation. METHODS: A broad range of methods was applied to elucidate the impact of bee venom on neoplastic cells. These included MTT assay for detection of cytotoxicity, immunostaining of cytosine modifications and mitochondria, assessment of cellular morphology by flow cytometry, and quantification of mitochondrial DNA copy numbers using QPCR. RESULTS: Bee venom-induced cell death was selective for cancer cells, where it triggered a response characterized by alteration of cytosine modification. In contrast, normal cells were more resistant to DNA modifications. Furthermore, application of the venom resulted in variation of mitochondrial membrane permeability and mitochondrial DNA copy numbers, together with alterations in cell morphology, manifesting as reduced affected cell size. CONCLUSION: The study findings suggest that bee venom can be used as a selective DNA (de)methylating agent in cancer. Various agents (such as decitabine and 5-azacytidine) have been synthesized and developed for cancer treatment, and a range of syntheses and preparation and application methods have been described for these patented drugs. However, to the best of our knowledge, no previous research has investigated the use of bee venom or any component thereof for epigenetic therapy in cancer cells.

Pollen Beads: A New Carrier for Propolis Active Compounds.

BACKGROUND: Pollen and propolis are two bee products with highly health promoting properties. But there are some limitations of raw propolis usage not only in daily consumption but also in putting it in food formulations. Propolis should be extracted to convert it into consumable form and ethanol is the first choice as a solvent. But ethanol consumption, either in health-wise or religious aspect, is one of the factors limiting the usage of propolis extract. The strong taste and strong smell of propolis are other factors. The immobilization of propolis active compounds could be a tool for overcoming either all or some of these factors. OBJECTIVE: This study was aimed at the immobilization of propolis active constituents on the surface of whole pollen grains. METHODS: Chemical composition of raw propolis was determined by using GC-MS technique. Total phenolic content and antioxidant activity of the samples were measured spectrophotometrically. The release property of the beads was determined. RESULTS: Immobilization efficiency was 53%. Total phenolic and flavonoid content of pollen, propolis and pollen-propolis beads were measured. It was determined that pollen-propolis beads contain more phenolics than pollen and propolis itself. Ferric reducing activity of the samples was also investigated and pollen-propolis beads showed better activity. Release behavior of pollen and pollen-propolis beads was studied in simulated digestive systems. Better release properties of pollen-propolis beads were achieved in all tested systems as well. These findings support the immobilization of propolis active compounds on the surface of whole pollen grains. CONCLUSION: It could be concluded that the product obtained, pollen-propolis beads, could be considered as a more valuable healthy product since the synergistic action of pollen and propolis.

Comparison between Phenolic Content, Antioxidant, and Antibacterial Activity of Algerian and Turkish Propolis.

BACKGROUND: Propolis is a natural resinous material produced by honeybees. The biological activity and phenolic profile of propolis were largely studied all over the world. However, only a few investigations have been carried out on Algerian and Turkish propolis. The aim of the present study was to compare the phenolic content, antioxidant, and antibacterial activity of propolis samples collected from different localities of Algeria and Turkey. METHODS: Propolis extracts were performed using maceration in ethanol 80%. Total phenolic and flavonoid contents were determined. Antioxidant and antibacterial activities were evaluated using FRAP assay and the MIC was determined against four bacterial strains (S. aureus ATCC 25923, E. coli ATCC 25922, P. aeruginosa ATCC 27853 and K. pneumonia). RESULTS: TP varied from 19.51 ± 0.86 to 219.66 ± 1.23 mg GAE/g. Whereas, TF varied from 5.27± 0.07 to 74.57 ± 1.03 QE/g. All samples showed good ferric reducing antioxidant power ranging from 267.30 ± 4.77 to 2387.30 ± 44.15 µmol Trolox eq./g. All Algerian propolis samples displayed a more pronounced activity against S. aureus ATCC 25923 with MIC values ranging from 0,04 ± 0.00 mg/mL to 0.30±0.06 mg/Ml, with an activity 30 times more powerful than Anatolian propolis. While, Anatolian propolis samples were most active against P. aeruginosa ATCC 27853 with MIC values ranging from 0.20±0.00 mg/mL to 0.60±0.00 mg/Ml, with an activity 5 to 10 times more powerful than Algerian propolis. CONCLUSION: Algerian and Anatolian propolis possessed considerable phenolic and flavonoids contents. In addition, they exhibited interesting antioxidant and antibacterial activities. Our findings suggest that both propolis could be useful in the food and pharmaceutical industries.

Anti-Ulcerogenic and Cytoprotective Effects of Saharian (Sidr) Honey from Algeria.

AIM AND OBJECTIVE: This study aimed at investigating the gastro-protective effects of Algerian Sahara (Sidr) honey from Apis mellifera intermissa against HCl/Ethanol-induced gastric ulcers in rats. MATERIALS AND METHODS: Total phenolic content, antioxidant activity and phenolic compounds were determined. Then, three groups of rats (control, HCl/ Ethanol-induced ulcer, and orally administered honey) were used for the determination of gastro-protective effect of Sidr honey. RESULTS: Total phenolic content, total flavonoid content, and DPPH activity of the honey sample were determined as 47.35±3.35 mg GAE/ 100 g, 2.13±0.17 mg QE/ 100 g, and 229.24±0.02 mg/mL, respectively. Oral pretreatment of rats with honey (1.2 g/Kg body weight orally at an interval of 2 days) protected gastric mucosa against HCl/Ethanol-induced damage by decreasing ulcer score, the volume and acidity of gastric juice and increasing pH. CONCLUSION: These results were confirmed by the histological assessment, which demonstrated a significant gastro-protective activity of Saharian (Sidr) honey against HCl/Ethanol-induced stomach ulcer. Plasma tumor necrosis factor-α, IL-6 and PGE2 were also measured. Sahara honey significantly decreased the plasma TNF-α, PGE2, and IL-6 concentrations.

In vivo and in vitro anti-diabetic activity of ethanolic propolis extract.

The study investigated whether ethanolic propolis extract would exhibit an anti-diabetic effect in rats. The animals were divided into four groups of five rats each. Diabetic rats received 30% or 15% propolis extract at a dosage of 0.5 ml/100 g for 4 weeks. Data for the diabetic groups treated with 30% and 15% propolis showed a decrease in blood sugar levels from 393 ± 192.7 to 154 ± 28.0 mg/dl and from 386 ± 141.1 to 331.5 ± 123.74 mg/dl, respectively. Compared with the diabetic control group, an improvement was observed in both groups treated with propolis at the pancreatic, hepatic, and renal tissue levels. Antioxidant capacity, phenolic analysis, and the inhibition of α-amylase and α-glucosidase were also tested using the propolis samples to support in vivo data. Chrysin and caffeic acid phenyl ester were the dominant phenolics. The IC50 results for α-amylase (0.62 ± 0.00 µg/ml) and α-glucosidase (40.40 ± 0.09 µg/ml) were also encouraging. PRACTICAL APPLICATIONS: Bee products, non-synthetic compounds including propolis, are of great interest due to their potential therapeutic effects in metabolic disorders. The current study was designed and is now reported in order to confirm this potential benefit. The results obtained indicate that the higher concentration (30%) of ethanolic propolis extract exhibited excellent potential anti-diabetic activity by reducing blood sugar levels in diabetic rats. In addition, compared to the diabetic rat group, this extract exhibited a promising effect on the pancreatic, hepatic, and renal tissues of the propolis-treated groups. The current results indicate that propolis is a remarkable natural product with clinical potential in the treatment of diabetic disease.

Protective effects of aqueous extracts of some honeys against HCl/ethanol-induced gastric ulceration in rats.

This study focused on the concept of the possible protective effect of some honey types against HCl/ethanol-induced gastric ulcers in male Wistar albino rats. Rats were pretreated with rhododendron, chestnut, and oak honey orally with doses of 1.25 and 2.5 g/kg, bw (body weight) for three consecutive days. On fourth day, nothing was applied, and after the administration of anesthesia on the fifth day, their stomachs were surgically removed to investigate the histopathological examinations. Besides analyses of some blood serum profiles and antioxidant parameters of gastric tissue, some biochemical properties of honeys were investigated to support the histopathological results. The degrees of ulcer lesions in all groups revealed a statistically significant difference (p = .011). Although this difference originated from the additional ulcerative inducing effect of some honeys, the lower concentration rhododendron honey indicated more promising data than the positive control group (pantoprazole) in consequence of the microscopic and macroscopic evaluations. PRACTICAL APPLICATIONS: As being a member of natural products, honey has acquired fame among the studies in recent years due to its versatility as a source of food and complementary medicine. For contributing to this argument, this comprehensive study was performed and results were focused on the lower concentration of rhododendron honey thanks to its clinical potential with protecting the gastric mucosa. According to the obtained results, our suggestion came into prominence that this honey might be protecting the mucosa, better than the different concentrations of chestnut and oak honeys, by being better-absorbed through the gastric mucosa.

Apitherapy products enhance the recovery of CCL4-induced hepatic damages in rats.

BACKGROUND/AIM: Our objective was to identify the antioxidant properties of honeybee products from Turkey, chestnut honey, pollen, propolis, and royal jelly, and their hepatoprotective activity against CCl4-induced hepatic damage in rats. MATERIALS AND METHODS: Animals were fed with honeybee products for 7 days following CCl4 injection. Development of liver damage and oxidative stress were monitored by measuring the activities of the enzymes alanine transaminase, aspartate transaminase, malondialdehyde, superoxide dismutase, and catalase. Antioxidant capacities of the bee products were identified using FRAP and DPPH assays, as well as by measuring total phenolic and flavonoid contents. RESULTS: The antioxidant activities of the honeybee products were highest in propolis, followed, in order, by pollen, honey, and royal jelly. Despite their different levels of antioxidant capacity, their roles in the prevention of liver damage induced by CCl4 were very similar, which can be explained through their bioavailability to the treated animals. CONCLUSIONS: Our results suggest that honey, propolis, pollen, and royal jelly significantly enhanced the healing of CCl4-induced liver damage, partially due to their antioxidant properties and bioavailability.

Inhibition properties of propolis extracts to some clinically important enzymes.

The present study was conducted to envisage inhibition effects of propolis on the crucial enzymes, urease, xanthine oxidase (XO) and acetylcholinesterase (AChE). Some of the antioxidant properties of the propolis samples were determined using the total phenolic content (TPE) and total flavonoids in the eight different ethanolic propolis extracts (EPE) samples. Inhibition values of the enzymes were expressed as inhibition concentration (IC50; mg/mL or µg/mL) causing 50% inhibition of the enzymes with donepezil, acetohydroxamic acid and allopurinol as reference inhibitors. All the propolis extracts exhibited variable inhibition effects on these enzymes, but the higher the phenolic contents the lower the inhibitions values (IC50 = 0.074 to 1.560 mg/mL). IC50 values of the P5 propolis sample having the highest TPE, obtained from Zonguldak, for AChE, urease and XO were 0.081 ± 0.009, 0.080 ± 0.006 and 0.074 ± 0.011 µg/mL, respectively. The EPE proved to be a good source of inhibitor agents that can be used as natural inhibitors to serve human health.

Effects of Mad Honey on Some Biochemical Parameters in Rats.

The aims of this study were to determine grayanotoxin (GTX-III) toxin level in mad honey using liquid chromatography-tandem mass spectrometry and examine the dynamic changes of certain biochemical parameters in blood serum of rats that consumed mad honey. For the experimental animal study, 20 Sprague-Dawley female rats were divided into 5 groups of 4 rats each, with one group being the control group (Group 1) and the others being the experimental groups (Groups 2-5). Groups 2, 3, 4, and 5 were, respectively, given mad honey extract at doses of 0.3, 0.6, 1.2, and 2.4 mg/g body weight/day via oral gavage for 8 days. According to results, the quantity of GTX-III found in the honey sample as 39.949 ± 0.020 µg GTX-III/g honey, and the biochemical analysis of the tested parameters (aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, alkaline phosphatase, creatine kinase, and creatine kinase muscle and brain) showed a significant elevation with increasing concentration of honey. In conclusion, the use of increasing concentrations of Rhododendron honey was seen as a source of enzymatic symptoms.

A Member of Complementary Medicinal Food: Anatolian Royal Jellies, Their Chemical Compositions, and Antioxidant Properties.

This study investigated various chemical and antioxidant properties of Anatolian royal jelly samples. Moisture, pH, total protein, 10-hydroxy-2-decenoic acid (10-HDA) and sugars were analyzed from 18 samples. Total phenolic contents, ferric reducing antioxidant capacity and 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity were measured as antioxidant determinants. 10-HDA contents and total protein content of fresh weight ranged between 1.0% and 3.9%, and 11.4% and 15.8%, respectively. The main sugars detected were glucose and fructose. Maltose, trehalose, and melibiose were detected at less than 1.0% in all samples. Lactose, a milk sugar, was detected in only 3 samples, at values between 0.8% and 1.4%. Total henolic content ranged from 91.0 to 301.0 mg gallic acid equivalents/kg fresh weight. Antioxidant activity is due to both to the total phenolic content, proteins and fatty acids of royal jelly. Anatolian royal jelly samples were not different from other royal jelly samples from across the world.

An investigation of Turkish honeys: their physico-chemical properties, antioxidant capacities and phenolic profiles.

This study investigated some physico-chemical and biochemical characteristics of different honey types belonging to Turkish flora. Sixty-two honey samples were examined on the basis of pollen analyses, including 11 unifloral honeys (chestnut, heather, chaste tree, rhododendron, common eryngo, lavender, Jerusalem tea, astragalus, clover and acacia), two different honeydew honeys (lime and oak), and 7 different multifloral honeys. Electrical conductivity, moisture, Hunter color values, HMF, proline, diastase number, and sugar analyses of the honey samples were assessed for chemical characterization. Some phenolic components were analyzed by reverse phase high performance liquid chromatography (RP-HPLC) to determine honeys' phenolic profiles. Total phenolic compounds, total flavonoids, ferric reducing antioxidant capacity (FRAP) and 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity were measured as antioxidant determinants. The study results confirm that physico-chemical and biological characteristics of honeys are closely related to their floral sources, and that dark-colored honeys such as oak, chestnut and heather, have a high therapeutic potential.

Polyphenol oxidase activity and antioxidant properties of Yomra apple (Malus communis L.) from Turkey.

In this study, firstly, antioxidant and polyphenol oxidase (PPO) properties of Yomra apple were investigated. Seventeen phenolic constituents were measured by reverse phase-high-performance liquid chromatography (RP-HPLC). Total phenolic compounds (TPCs), ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activities were performed to measure antioxidant capacity. Some kinetic parameters (Km, Vmax), and inhibition behaviors against five different substrates were measured in the crude extract. Catechin and chlorogenic acid were found as the major components in the methanolic extract, while ferulic acid, caffeic acid, p-hydroxybenzoic acid, quercetin and p-coumaric acid were small quantities. Km values ranged from 0.70 to 10.10 mM in the substrates, and also 3-(4-hydroxyphenyl) propanoic acid (HPPA) and L-DOPA showed the highest affinity. The inhibition constant of Ki were ranged from 0.05 to 14.90 mM against sodium metabisulphite, ascorbic acid, sodium azide and benzoic acid, while ascorbic acid and sodium metabisulphite were the best inhibitors.

Hepatoprotective potential of chestnut bee pollen on carbon tetrachloride-induced hepatic damages in rats.

Bee pollen has been used as an apitherapy agent for several centuries to treat burns, wounds, gastrointestinal disorders, and various other diseases. The aim of our study was to investigate the hepatoprotective effects of chestnut bee pollen against carbon tetrachloride (CCI4)-induced liver damage. Total phenolic content, flavonoid, ferric reducing/antioxidant power, and DPPH radical activity measurements were used as antioxidant capacity determinants of the pollen. The study was conducted in rats as seven groups. Two different concentrations of chestnut bee pollens (200 and 400 mg/kg/day) were given orally and one group was administered with silibinin (50 mg/kg/day, i.p.) for seven days to the rats following the CCI4 treatment. The protective effect of the bee pollen was monitored by aspartate transaminase (AST) and alanine transaminase (AST) activities, histopathological imaging, and antioxidant parameters from the blood and liver samples of the rats. The results were compared with the silibinin-treated and untreated groups. We detected that CCI4 treatment induced liver damage and both the bee pollen and silibinin-treated groups reversed the damage; however, silibinin caused significant weight loss and mortality due, severe diarrhea in the rats. The chestnut pollen had showed 28.87 mg GAE/g DW of total phenolic substance, 8.07 mg QUE/g DW of total flavonoid, 92.71 mg Cyn-3-glu/kg DW of total anthocyanins, and 9 mg ß -carotene/100 g DW of total carotenoid and substantial amount of antioxidant power according to FRAP and DPPH activity. The results demonstrated that the chestnut bee pollen protects the hepatocytes from the oxidative stress and promotes the healing of the liver damage induced by CCI4 toxicity. Our findings suggest that chestnut bee pollen can be used as a safe alternative to the silibinin in the treatment of liver injuries.

Composition and antimicrobial activity of essential oils from Centaurea sessilis and Centaurea armena.

The essential oils of air-dried Centaurea sessilis and Centaurea armena obtained by hydrodistillation were analyzed by gas chromatography-mass spectrometry (GC-MS). Forty and twenty components were identified in the essential oils and the main component of these taxons was beta-eudesmol in the ratios of 12.4% and 19.3% from C. sessilis and C. armena, respectively. The antimicrobial activity of the isolated essential oil of the plants was also investigated. They showed moderate antibacterial activity against Gram-positive and Gram-negative bacteria, but no antifungal activity was observed against two yeastlike fungi.