Antibacterial activity of Hungarian varietal honeys against respiratory pathogens as a function of storage time.

Today, antibiotic therapies that previously worked well against certain bacteria due to their natural sensitivity, are becoming less effective. Honey has been proven to inhibit the biofilm formation of some respiratory bacteria, however few data are available on how the storage time affects the antibacterial effect. The activity of black locust, goldenrod, linden and sunflower honeys from three consecutive years (2020, 2021, 2022) was analyzed in 2022 against Gram-negative (Haemophilus influenzae, H. parainfluenzae, Pseudomonas aeruginosa) and Gram-positive (Streptococcus pneumoniae) bacteria using in vitro microbiological methods. After determining the physicochemical parameters of honey, broth microdilution was applied to determine the minimum inhibitory concentration of each honey type against each bacterium, and crystal violet assay was used to test their antibiofilm effect. The possible mechanism of action was explored with membrane degradation test, while structural changes were illustrated with scanning electron microscopy. Honeys stored for one or two years were darker than fresh honeys, while older honeys had significantly lower antibacterial activity. The most remarkable inhibitory effect was exerted by linden and sunflower honeys, and P. aeruginosa proved to be the most resistant bacterium. Based on our results, honey intended for medicinal purposes should be used as fresh as possible during a treatment.

Application of Alcohols to Inhibit the Formation of Ca(II) Dodecyl Sulfate Precipitate in Aqueous Solutions.

The presence of alkaline earth cations, in particular, Ca2+ and Mg2+ ions in brine, causes undesired effects in solutions containing anionic surfactants because of precipitate formation. In the present study, an anionic surfactant, sodium dodecyl sulfate (SDS), was investigated, focusing on the determination of various properties (surface tension, critical micelle concentration, micelle size, turbidity) in the presence of alcohols and, in particular, the inhibition of the precipitation of SDS with calcium ions. The calcium ions were added to the surfactant in increasing concentrations (3.0-10.0 g/L), and short-carbon-chain alcohols (methanol, ethanol, n-propanol and n-butanol) were used to shift the onset of precipitate formation. The critical micelle concentration (CMC) of SDS in the presence of alcohols was also determined. It was established that among these alcohols, methanol and ethanol did not exert significant effects on the solubility of the Ca(DS)2 precipitate, while n-propanol and n-butanol were found to be much more efficient inhibitors. In addition, all the alcohols in the applied concentration range (up to 20 V/V%) were found to decrease the critical micelle concentration of SDS.

Chestnut Honey Is Effective against Mixed Biofilms at Different Stages of Maturity.

The irresponsible overuse of antibiotics has increased the occurrence of resistant bacterial strains, which represents one of the biggest patient safety risks today. Due to antibiotic resistance and biofilm formation in bacteria, it is becoming increasingly difficult to suppress the bacterial strains responsible for various chronic infections. Honey was proven to inhibit bacterial growth and biofilm development, offering an alternative solution in the treatment of resistant infections and chronic wounds. Our studies included chestnut honey, valued for its high antibacterial activity, and the bacteria Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and S. epidermidis, known to form multi-species biofilm communities. Minimum inhibitory concentrations (MIC) of chestnut honey were determined for each bacterial strain. Afterwards, the mixed bacterial biofilms were treated with chestnut honey at different stages of maturity (incubation times: 2, 4, 6, 12, 24 h). The extent of biofilm inhibition was measured with a crystal violet assay and demonstrated by scanning electron microscopy (SEM). As the incubation time increased and the biofilm became more mature, inhibition rates decreased gradually. The most sensitive biofilm was the combination MRSA-S. epidermidis, with a 93.5% inhibition rate after 2 h of incubation. Our results revealed that chestnut honey is suitable for suppressing the initial and moderately mature stages of mixed biofilms.

Medicinal-Chemistry-Driven Approach to 2-Substituted Benzoxazole-Estradiol Chimeras: Synthesis, Anticancer Activity, and Early ADME Profile.

The efficient synthesis of novel estradiol-based A-ring-fused oxazole derivatives, which can be considered as benzoxazole-steroid domain-integrated hybrids containing a common benzene structural motif, is described. The target compounds were prepared from steroidal 2-aminophenol precursors by heterocycle formation or functional group interconversion (FGI) strategies. According to 2D projection-based t-distributed stochastic neighbor embedding (t-SNE), the novel molecules were proved to represent a new chemical space among steroid drugs. They were characterized based on critical physicochemical parameters using in silico and experimental data. The performance of the compounds to inhibit cell proliferation was tested on four human cancer cell lines and non-cancerous cells. Further examinations were performed to reveal IC50 and lipophilic ligand efficiency (LLE) values, cancer cell selectivity, and apoptosis-triggering features. Pharmacological tests and LLE metric revealed that some derivatives, especially the 2-(4-ethylpiperazin-1-yl)oxazole derivative exhibit strong anticancer activity and trigger the apoptosis of cancer cells with relatively low promiscuity risk similarly to the structurally most closely-related and intensively studied anticancer agent, 2-methoxy-estradiol.

Phenolic compounds in Hungarian acacia, linden, milkweed and goldenrod honeys.

Honey is a valuable source of nutrients, minerals and phenolic compounds. Phenolic acids and flavonoids are associated with health benefits of honey and can serve as markers for distinguishing honey types. This study aimed at determining the phenolic profile of four Hungarian unifloral honeys that were not analyzed previously. After verifying their botanical origin with melissopalynological analysis, total reducing capacity was determined with Folin-Ciocalteau method, and phenolic composition was analyzed with HPLC-DAD-MS. From the 25 phenolic substances examined, pinobanksin was the most abundant, followed by chrysin, p-hydroxybenzoic acid and galangin. Quercetin and p-syringaldehyde were detected only in acacia honey, which contained higher levels of chrysin and hesperetin compared to the other three honeys. Milkweed and linden honeys displayed higher levels of caffeic, chlorogenic, ferulic and p-coumaric acids compared to acacia and goldenrod honeys. Taxifolin may serve as a unique marker compound of milkweed honey. Goldenrod honey contained the highest level of syringic acid. Principal component analysis supported the indicator role of polyphenols in honey identification, discriminating clearly the four unifloral honeys. Our results suggest that phenolic profiles may be useful to find markers of honey's floral origin, but geographical origin can strongly influence the composition of characteristic compounds.

Antibacterial and Antibiofilm Effect of Unifloral Honeys against Bacteria Isolated from Chronic Wound Infections.

Honey is known as an alternative remedy for the treatment of wounds. To evaluate the potential of five Hungarian honey types against wound-associated bacteria, in vitro microbiological assays were conducted on Pseudomonas aeruginosa, Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus (MRSA). Minimum inhibitory concentration (MIC) was determined with the broth macrodilution method, and biofilm degradation capacity was tested with a crystal violet assay. To understand the underlying mechanisms, the effects of honey treatments were assessed on bacterial membrane integrity and quorum sensing (QS). The highest antibacterial activity, indicated by the lowest MIC values, as well as the highest biofilm inhibition rates and membrane disruption, was displayed by chestnut and linden honeys. The most sensitive bacterium was S. epidermidis. Bacterial membrane degradation took place 40 min after treatment with honey solutions of at least a 40% concentration. Each honey sample exhibited anti-QS activity, which was most pronounced in the case of chestnut honey. It was concluded that the antibacterial, biofilm-inhibiting and anti-QS activities of linden and chestnut honeys were superior to those of acacia, goldenrod and milkweed honeys. In addition to the floral source, the antibacterial effect of honey is influenced by the microbial species treated. The use of honey in wound treatment can be justified by its diverse antibacterial mechanisms.

The Importance of Pine Species in the Ethnomedicine of Transylvania (Romania).

The geographical and ecological features of Transylvania enable the wide ethnobotanical use of pine species. The aim of this study was to survey the current ethnomedicinal and other traditional use of pine species of Hungarian-speaking ethnic groups in Transylvania and to compare them with earlier reports performed in Transylvania and from other countries related to the Carpathian Basin. Information on pine species was obtained using semi-structured interviews with 515 Transylvanian informants from 18 villages in the period 2007-2019. The young shoots of Abies alba Mill., Picea abies (L.) H. Karst., Pinus nigra J. F. Arnold, and Pinus sylvestris L. were applied to treat respiratory diseases, while the resin was used for dental problems. Syrup and decoction were made from the cones of all species, except Abies alba. Picea abies was the most frequently documented with seven preparations from different parts (even needles), and this species was mentioned in the treatment of 21 diseases. The least recorded was Abies alba, which was applied for coughs and decayed teeth. We recorded the use of the cones and needles of Picea abies for dyspnoea, thyroid glands, and kidney disorders, previously unknown in ethnomedicinal literature. Our data on the pine species confirm their current use and significance in Transylvania.

Antibacterial and Biofilm Degradation Effects of Hungarian Honeys Linked With Botanical Origin, Antioxidant Capacity and Mineral Content.

The aim of the study was to assess the impact of four unifloral honeys on the food-borne pathogens Pseudomonas aeruginosa and Staphylococcus aureus, by analyzing the honeys' antibacterial and biofilm degradation effects, as well as their antioxidant activity and element content. Linden and milkweed honeys represented light colored honeys, while goldenrod and chestnut honeys the darker ones. The botanical origin of the honeys and the relative frequency of their pollen types were established with melissopalynological analysis. The antioxidant capacities were calculated by two single electron transfer based methods (TRC - Total Reducing Capacity and TEAC - Trolox Equivalent Antioxidant Capacity) and a hydrogen atom transfer based assay (ORAC - Oxygen Radical Absorbance). The amount of four main macro- and two microelements was quantified. The antibacterial activity was determined by minimum inhibitory concentration (MIC) and membrane degradation assays. Furthermore, the biofilm degradation power of the samples was studied as well. The light colored linden honey with the lowest TRC and TEAC, but with the highest ORAC antioxidant activity and high element content showed the best antibacterial and biofilm degradation effects. Meanwhile, the dark colored chestnut honey with significantly higher single electron transfer based antioxidant capacities, with high element content, but lower ORAC showed significantly higher MIC and lower membrane degradation activity than linden honey. In case of biofilm degradation, both honey types gave similarly high inhibitory effect. Goldenrod honey was similarly effective regarding its MIC properties like chestnut honey, but had significantly lower antioxidant potential and ability to disrupt bacterial membranes and biofilms. Milkweed honey was the honey type with the lowest bioactivity and element content. The honeys, unequivocally characterized by their antioxidant characters and element content, displayed different antibacterial and biofilm degradation effects. In addition, some honey traits were found to be good predictors of the antimicrobial potential of honeys: ORAC assay showed correlation with the MIC values of both bacteria, and strict correlation was found between the mineral content and the antibiofilm activity of the studied honeys. Our studies indicate that unifloral honeys, such as linden and chestnut honeys, are plant-derived products with great potential as antimicrobial agents in food preservation, exhibiting remarkable antibacterial activity against food-borne pathogens.

Antioxidant Capacity Determination of Hungarian-, Slovak-, and Polish-Origin Goldenrod Honeys.

The goldenrod (Solidago) species are flowering plants that produce nectar and can be the sources of unifloral honeys. S. canadensis and S. gigantea are native to North America and invasive in several European countries, while S. virgaurea is native to Europe. The aim of this work was to determine and compare the antioxidant capacity of goldenrod honeys collected in three central European countries (Hungary, Poland, and Slovakia), from three locations within each country. The botanical origin of each honey sample was checked with melissopalynological analysis. Color intensity was determined using the Pfund scale. The antioxidant activity was determined with different spectrophotometric methods (DPPH, ABTS, and FRAP). The content of total polyphenols, flavonoids, and phenolic acids was quantified using spectrophotometric methods. The highest radical-scavenging activity was identified for Hungarian samples with all three antioxidant capacity assays. Medium antioxidant activity was described for Slovak samples. The DPPH and ABTS assays discriminated Polish honeys with the lowest antioxidant activity. The highest flavonoid and phenolic acid content was detected in Hungarian and Slovak honeys, while the lowest values were measured in Polish samples. Our study shows that the antioxidant capacity of unifloral goldenrod honeys can be different in various countries of origin, correlating with color intensity and polyphenol content.

Evaluation of Total Phenolic and Flavonoid Contents, Antibacterial and Antibiofilm Activities of Hungarian Propolis Ethanolic Extract against Staphylococcus aureus.

Propolis is a natural bee product that is widely used in folk medicine. This study aimed to evaluate the antimicrobial and antibiofilm activities of ethanolic extract of propolis (EEP) on methicillin-resistant and sensitive Staphylococcus aureus (MRSA and MSSA). Propolis samples were collected from six regions in Hungary. The minimum inhibitory concentrations (MIC) values and the interaction of EEP-antibiotics were evaluated by the broth microdilution and the chequerboard broth microdilution methods, respectively. The effect of EEP on biofilm formation and eradication was estimated by crystal violet assay. Resazurin/propidium iodide dyes were applied for simultaneous quantification of cellular metabolic activities and dead cells in mature biofilms. The EEP1 sample showed the highest phenolic and flavonoid contents. The EEP1 successfully prevented the growth of planktonic cells of S. aureus (MIC value = 50 µg/mL). Synergistic interactions were shown after the co-exposition to EEP1 and vancomycin at 108 CFU/mL. The EEP1 effectively inhibited the biofilm formation and caused significant degradation of mature biofilms (50-200 µg/mL), as a consequence of the considerable decrement of metabolic activity. The EEP acts effectively as an antimicrobial and antibiofilm agent on S. aureus. Moreover, the simultaneous application of EEP and vancomycin could enhance their effect against MRSA infection.

Quality Assessment of Goldenrod, Milkweed and Multifloral Honeys Based on Botanical Origin, Antioxidant Capacity and Mineral Content.

The goal of the study was to evaluate the pollen spectrum, antioxidant capacity and mineral content of four Hungarian honey types, using multivariate statistical analysis. The light colored honeys were represented by milkweed honey and a multifloral (MF) honey with dominant pollen frequency of linden (MF-Tilia); the darker ones were goldenrod honey and a multifloral honey with Lamiaceae pollen majority (MF-Lamiaceae). The pollen spectrum of the samples was established with melissopalynological analysis. The absorbance of the honeys positively correlated with the antioxidant capacity determined with three of the used methods (TRC, TEAC, DPPH), but not with ORAC. The latter method correlated negatively also with other antioxidant methods and with most of the mineral values. MF-Tilia had high ORAC value, K and Na content. The MF-Lamiaceae had the highest K, Mg, P, S, Cu and Zn content, the last five elements showing strict correlation with the TRC method. The darker goldenrod honey had higher SET values and total mineral content, than the milkweed honey. The above character-sets facilitate identification of each honey type and serve as indicators of variety. The antioxidant levels and mineral content of honeys allowed their clear separation by principal component analysis (PCA).

Copper-Loaded Layered Bismuth Subcarbonate-Efficient Multifunctional Heterogeneous Catalyst for Concerted C-S/C-N Heterocyclization.

An efficient self-supported Cu(II)Bi(III) bimetallic catalyst with a layered structure was designed and developed. By careful characterization of the as-prepared material, the host structure was identified to exhibit a Sillen-type bismutite framework, with copper(II) ions being loaded as guests. The heterogeneous catalyst enabled C-N and C-S arylations under mild reaction conditions and with high chemoselectivities, thus furnishing valuable phenothiazines via heterocyclization with wide substrate tolerance. As corroborated by detailed catalytic studies, the cooperative, bifunctional catalyst, bearing Lewis acid sites along with copper(II) catalytic sites, facilitated an intriguing concerted C-N/C-S heterocyclization mechanism. The heterogeneous nature of the catalytic reactions was verified experimentally. Importantly, the catalyst was successfully recycled and reused multiple times, persevering its original structural order as well as its initial activity.

In Vitro Antibacterial and Antibiofilm Activity of Hungarian Honeys against Respiratory Tract Bacteria.

Honey is a rich source of carbohydrates, while minor compounds such as amino acids and polyphenols contribute to its health-promoting effects. Honey is one of the oldest traditional remedies applied for microbial infections, due to its antibacterial, anti-inflammatory, and antioxidant properties. The aim of this study was to investigate the antibacterial and antibiofilm effects of Hungarian black locust, linden, and sunflower honeys against the most common biofilm-forming respiratory tract pathogens Haemophilus spp., Pseudomonas aeruginosa, and Streptococcus pneumoniae. The unifloral character of all three honey types was confirmed by melissopalynological analysis. The antibacterial activity of each honey sample against each bacterium strain was proven with agar well diffusion assay and thin layer chromatography-direct bioautography. Kinetics and mechanisms of antibacterial action were clarified with time-kill assay and membrane degradation study. The anti-biofilm activity was evidenced using crystal violet assay. In each assay, linden honey was the most effective, followed by sunflower and black locust honey. In addition, each honey sample had greater potential to suppress respiratory tract bacteria, compared to major sugar components. In conclusion, honey in general and linden honey in particular, can have a role in the treatment of respiratory tract infections caused by biofilm-forming bacteria.

Quality Evaluation of Light- and Dark-Colored Hungarian Honeys, Focusing on Botanical Origin, Antioxidant Capacity and Mineral Content.

Melissopalynology, antioxidant capacity and mineral and toxic element contents were analyzed in eight types of Hungarian honeys. Based on color, two groups were distinguished: light honeys comprised acacia, amorpha, phacelia and linden honeys; while dark honeys included sunflower, chestnut, fennel and sage honeys, with 100 to 300 and 700 to 1500 mAU, respectively. The unifloral origin of each sample was supported using pollen analysis. The absorbance of honey correlated positively with antioxidant capacity determined by three different methods (TRC, DPPH, ORAC), and also with mineral content. The exception was the light amber linden honey with significantly higher K content and antiradical activity than other light honeys. The Mn, Zn and Fe contents were the highest in chestnut, sunflower and fennel honeys, respectively. The black meadow sage honey performed best regarding the content of other elements and antioxidant activity. The concentrations of several toxic elements were below the detection limit in the samples, indicating their good quality. The principal component analysis (PCA) revealed correlations between different antioxidant assays and minerals, and furthermore, confirmed the botanical authentication of the honeys based on the studied parameters. To our best knowledge, the present study is the first to provide a complex analysis of quality parameters of eight unifloral Hungarian honeys.

Soil Humus, Iron, Sulphate and Magnesium Content Affect Nectar Traits of Wild Garlic (Allium ursinum L.).

Recent studies revealed that from various ecological factors influencing nectar yield and quality of a plant, soil properties can be as important as microclimatic features. To date, few studies have investigated the relationship of soil characters to nectar traits of bee pollinated plants growing in natural associations. Our study intended to reveal which soil properties had the most powerful impact on nectar variables of wild garlic (Allium ursinum L.). Specimens were collected from fourteen habitats in two different years, and were potted in their original soil under the same climatic conditions. Nectar volumes and sugar concentrations were measured and soil samples were analysed for fourteen parameters. Statistical analyses revealed that the number of nectar producing Allium flowers, as well as the nectar volume and sugar content of nectar in individual flowers were influenced by both year and habitat. The humus, iron and sulphate content of soil showed negative correlation with the number of flowers producing nectar; total nectar volumes were negatively correlated with humus and iron content, but positively affected by magnesium content of the soil. Our results suggest that in addition to the effect of microclimatic factors, certain soil properties can have significant impact on nectar traits.

Analyzing the Carotenoid Composition of Melilot (Melilotus officinalis (L.) Pall.) Extracts and the Effects of Isolated (All-E)-lutein-5,6-epoxide on Primary Sensory Neurons and Macrophages.

Melilotus officinalis is known to contain several types of secondary metabolites. In contrast, the carotenoid composition of this medicinal plant has not been investigated, although it may also contribute to the biological activities of the drug, such as anti-inflammatory effects. Therefore, this study focuses on the isolation and identification of carotenoids from Meliloti herba and on the effect of isolated (all-E)-lutein 5,6-epoxide on primary sensory neurons and macrophages involved in nociception, as well as neurogenic and non-neurogenic inflammatory processes. The composition of the plant extracts was analyzed by high performance liquid chromatography (HPLC). The main carotenoid was isolated by column liquid chromatography (CLC) and identified by MS and NMR. The effect of water-soluble lutein 5,6-epoxide-RAMEB (randomly methylated-ß-cyclodextrin) was investigated on Ca2+-influx in rat primary sensory neurons induced by the activation of the transient receptor potential ankyrin 1 receptor agonist to mustard-oil and on endotoxin-induced IL-1ß release from isolated mouse peritoneal macrophages. (all-E)-Lutein 5,6-epoxide significantly decreased the percent of responsive primary sensory neurons compared to the vehicle-treated stimulated control. Furthermore, endotoxin-evoked IL-1ß release from macrophages was significantly decreased by 100 µM lutein 5,6-epoxide compared to the vehicle-treated control. The water-soluble form of lutein 5,6-epoxide-RAMEB decreases the activation of primary sensory neurons and macrophages, which opens perspectives for its analgesic and anti-inflammatory applications.

Strategies for RUN1 Deployment Using RUN2 and REN2 to Manage Grapevine Powdery Mildew Informed by Studies of Race Specificity.

The Toll/interleukin-1 receptor nucleotide-binding site leucine-rich repeat gene, "resistance to Uncinula necator 1" (RUN1), from Vitis rotundifolia was recently identified and confirmed to confer resistance to the grapevine powdery mildew fungus Erysiphe necator (syn. U. necator) in transgenic V. vinifera cultivars. However, sporulating powdery mildew colonies and cleistothecia of the heterothallic pathogen have been found on introgression lines containing the RUN1 locus growing in New York (NY). Two E. necator isolates collected from RUN1 vines were designated NY1-131 and NY1-137 and were used in this study to inform a strategy for durable RUN1 deployment. In order to achieve this, fitness parameters of NY1-131 and NY1-137 were quantified relative to powdery mildew isolates collected from V. rotundifolia and V. vinifera on vines containing alleles of the powdery mildew resistance genes RUN1, RUN2, or REN2. The results clearly demonstrate the race specificity of RUN1, RUN2, and REN2 resistance alleles, all of which exhibit programmed cell death (PCD)-mediated resistance. The NY1 isolates investigated were found to have an intermediate virulence on RUN1 vines, although this may be allele specific, while the Musc4 isolate collected from V. rotundifolia was virulent on all RUN1 vines. Another powdery mildew resistance locus, RUN2, was previously mapped in different V. rotundifolia genotypes, and two alleles (RUN2.1 and RUN2.2) were identified. The RUN2.1 allele was found to provide PCD-mediated resistance to both an NY1 isolate and Musc4. Importantly, REN2 vines were resistant to the NY1 isolates and RUN1REN2 vines combining both genes displayed additional resistance. Based on these results, RUN1-mediated resistance in grapevine may be enhanced by pyramiding with RUN2.1 or REN2; however, naturally occurring isolates in North America display some virulence on vines with these resistance genes. The characterization of additional resistance sources is needed to identify resistance gene combinations that will further enhance durability. For the resistance gene combinations currently available, we recommend using complementary management strategies, including fungicide application, to reduce populations of virulent isolates.

On the spectrophotometric determination of total phenolic and flavonoid contents.

Spectrophotometric assays assessing total phenol and flavonoid content in plant samples are cheaper and faster and thus more accessible methods than analytical chromatography techniques, although these identify compound categories rather than individual compounds. Most methods are used and are published in several varieties and their general (chemically unspecific) nature is often neglected. The aim of the present in vitro study was to compare five frequently used methods in terms of cross reactivity and sensitivity using pure phenolic substances. Test compounds were selected to represent categories of phenolic compounds of special interest in plant stress studies. Examining the classic Folin-Ciocalteu test we found that in addition to phenolics, it was also reactive to ascorbate. Three flavonoid assays were also examined. These are usually applied to quantify (i) flavonols using aluminium-chloride, (ii) flavanons and flavanonols using 2,4-dinitrophenyl-hydrazine or (iii) flavanols using 4-dimethylamino-cinnamaldehyde. We found that all three methods were unaffected by the presence of ascorbate, but only the last one was specific to the group of compounds aimed at. Our results show that cross reactivities to various flavonoid groups should be taken into account when interpreting data from these assays. Methods utilizing the UV absorption of phenolic compounds were also tested and analyses of whole spectra were found more accurate than estimates based on absorptions at single wavelengths.

Essential oil composition and preliminary molecular study of four Hungarian Thymus species.

Chemical and genetic differences of twenty taxa belonging to four Thymus species were studied in order to determine whether molecular characters and essential oil components could be used as taxonomic markers and to examine the correlation between them. Plant samples, representing different taxa and geographic regions, were collected from experimentally grown populations. Essential oil samples were analysed by GC/MS and cluster analysis of volatile composition resulted in segregation of thymol chemotypes from sesquiterpenic ones. Thymol was characteristic for all the populations of Thymus glabrescens and T. pannonicus as well as for certain taxa belonging to T. praecox and T. pulegioides. Sesquiterpenes occurred in only two taxa of T. glabrescens, in each sample of T. praecox and in three taxa of T. pulegioides. Plant samples were analysed by random amplified polymorphic DNA (RAPD). The obtained dendrogram revealed high gene diversity. The 13 primers resulted 114 polymorphic RAPD bands, and the average percentage of polymorphism was 80.8%. The RAPD dendogram showed separation neither at interspecific nor at interpopulational levels. Therefore, further specific molecular studies involving more taxa are suggested. Partial correlation have been found between molecular and chemical assessments.