Investigation of Thyme (Thymus vulgaris L.) Essential Oil by Use of the BioArena System

JPC – Journal of Planar Chromatography – Modern TLC - The composition of the essential oil of Thymus vulgaris L. has been determined by GC-FID and GC-MS. Because separation of thymol,...     

Direct Bioautographic Detection of Antibacterial Components of Clary Sage and Spearmint Essential Oils

JPC – Journal of Planar Chromatography – Modern TLC - The antibacterial effect of the components of clary sage (Salvia sclarea L.) and spearmint (Mentha spicata L. var. crispa (Bentham)...     

Antioxidant and antiacetylcholinesterase activities of some commercial essential oils and their major compounds

The commercial essential oils of Citrus aurantium L., Cupressus sempervirens L., Eucalyptus globulus Labill., Foeniculum vulgare Mill. and Thymus vulgaris L., isolated by steam distillation by a company of Morocco were evaluated in terms of in vitro antioxidant activity through several methods. In vitro acetylcholinesterase inhibitory activity was also determined. Citrus limon (L.) Burm. f. oil was also studied, but it was obtained by peel expression. The best antioxidant was T. vulgaris oil, independent of the method used, mainly due to the presence of the phenolic monoterpenes thymol and carvacrol, which when studied as single compounds also presented the best activities. Concerning the acetylcholinesterase inhibition activity, E. globulus was the most effective. Nevertheless its main components 1,8-cineole and limonene were not the most active, a feature that corresponded to d-3-carene.     

High-Performance Thin-Layer Chromatographic Quantification of Kaempferol and Apigenin in the Whole-Plant Powder of Sida spinosa Linn

JPC – Journal of Planar Chromatography – Modern TLC - Sida spinosa Linn. (synonyms: S. alba L., S. angustifolia Lam., S. angustifolia Mill.), Malvaceae, is an annual erect, branched...     

Ruta Essential Oils: Composition and Bioactivities

Ruta L. is a typical genus of the citrus family, Rutaceae Juss. and comprises ca. 40 different species, mainly distributed in the Mediterranean region. Ruta species have long been used in traditional medicines as an abortifacient and emmenagogue and for the treatment of lung diseases and microbial infections. The genus Ruta is rich in essential oils, which predominantly contain aliphatic ketones, e.g., 2-undecanone and 2-nonanone, but lack any significant amounts of terpenes. Three Ruta species, Ruta chalepensis L., Ruta graveolens L., and Ruta montana L., have been extensively studied for the composition of their essential oils and several bioactivities, revealing their potential medicinal and agrochemical applications. This review provides a systematic evaluation and critical appraisal of publications available in the literature on the composition and bioactivities of the essential oils obtained from Ruta species and includes a brief outlook of the potential applications of nanotechnology and chitosan-based products of Ruta essential oils.     

TLC and GC Analysis of the Essential Oils of Stachys Species

JPC – Journal of Planar Chromatography – Modern TLC - Species of the Lamioideae subfamily of the family Lamiaceae, including Stachys species, do not contain much essential oil. The...     

Oregano and Thyme Essential Oils Encapsulated in Chitosan Nanoparticles as Effective Antimicrobial Agents against Foodborne Pathogens

The use of natural compounds with biocidal activity to fight the growth of bacteria responsible for foodborne illness is one of the main research challenges in the food sector. This study reports the preparation and physicochemical characterization of chitosan nanoparticles loaded with Thymus capitatus (Th-CNPs) and Origanum vulgare (Or-CNPs) essential oils. The nanosystems were obtained by ionotropic gelation technique with high encapsulation efficiency (80–83%) and loading capacity (26–27%). Nanoparticles showed a spherical shape, bimodal particle size distribution, and good stability (zeta potential values > 40 mV). The treatment of the nanosuspensions at different temperatures (4 and 40 °C) and storage times (7, 15, 21, and 30 days) did not affect their physicochemical parameters and highlights their reservoir ability for essential oils also under stressful conditions. Both Or-CNPs and Th-CNPs exhibited an enhanced bactericidal activity against foodborne pathogens (S. aureus, E. coli, L. monocytogenes) than pure essential oils. These ecofriendly nanosystems could represent a valid alternative to synthetic preservatives and be of interest for health and food safety.     

Deuterium/hydrogen ratio analysis of thymol, carvacrol, gamma-terpinene and p-cymene in thyme, savory and oregano essential oils by gas chromatography-pyrolysis-isotope ratio mass spectrometry

Isotope ratio mass spectrometry online coupled with capillary gas chromatography (GC-Py-IRMS) on column INNOWAX is used in the origin specific analysis and the authenticity control of the phenolic essential oils (EOs). Isotopic data delta(2)H(V-SMOW) of thymol and carvacrol in natural essential oils were evidently more depleted than synthetic products (from -49 to 7 per thousand for thymol and -61 per thousand for carvacrol). delta(2)H(V-SMOW) values of p-cymene, gamma-terpinene and thymol in authentic thyme oils (Thymus vulgaris L. and Thymus zygis L.) were found from -300 to -270 per thousand, from -285 to -248 per thousand and from -259 to -234 per thousand, respectively. delta(2)H(V-SMOW) values of carvacrol and p-cymene in authentic oregano oils (Origanum heracleoticum L., Coridothymus capitatus L. and Origanum compactum L.) varied from -223 to -193 per thousand and from -284 to -259 per thousand, respectively. For authentic Satureja montana subsp. montana essential oils, the mean delta(2)H(V-SMOW) value for aromatic compounds were found to be the following: gamma-terpinene -273 per thousand (SD=4.6 per thousand) and p-cymene -283 per thousand (SD=3.0 per thousand), thymol -245 per thousand (SD=1.8 per thousand) and carvacrol -226 per thousand (SD=1.7 per thousand). In addition, p-cymene was previously found as a precursor of the biosynthesis of thymol and carvacrol in thyme oil, thus, we considered p-cymene as an endogenous reference compound (ERC) for D/H ratio analysis. The isotopic fractionation factors alpha(thymol/p-cymene)=1.05 and alpha(carvacrol/p-cymene)=1.08 were obtained and also used to control the authenticity of the phenolic EOs.     

Purification and characterization of anti-complementary polysaccharide from leaves of Thymus vulgaris L.

For the purification of the anti-complementary polysaccharide from Thymus vulgaris L., the hot-water extract of thyme leaves was successively fractionated by ethanol precipitation and ultra-filtration. The retentate with 300-kDa membrane cartridge showed a potent anti-complementary activity. It was further purified by open column chromatographies on DEAE-Toyopearl 650C, Butyl-Toyopearl 650M and Sephadex G-100, obtaining TV3-IIA-I, the purified anti-complementary polysaccharide. The anti-complementary polysaccharide exhibited the anti-complementary activity via both classical and alternative pathways. Based upon the methylation analysis and the reaction with beta-glucosyl Yariv reagent, the anti-complementary polysaccharide from thyme might contain an arabinogalactan moiety, at least in part.     

Fatty Acid Composition of Seed Oils of Twelve Salvia Species Growing in Turkey

Seed oils of 12 Salvia species collected from different regions in Turkey (S. Albimaculata Hedge & Hub.-Mor., S. Candidisima Vahl., S. Cedronella Boiss., S. Cryptantha Montbret & Aucher ex Bentham, S. Forskahlei L., S. Fruticosa Miller (Sin. S. Triloba L. Fil), S. Halophila Hedge, S. Hypargeia Fisch. & Mey., S. Sclarea L., S. Tomentosa Miller, S. Tchihatcheffii (Fisch. & Mey.) Boiss., S. Virgata Jacq.) were obtained by Soxhlet apparatus using hexane. The oil yields were found to be between 2.0% and 20.9%. Fatty acids in the oils were converted to methyl esters and determined by GC/MS in methyl ester form. The main fatty acid components of S. halophila, S. Hypargeia, and S. Sclarea are unsaturated oleic, linoleic, and linolenic acids. In others except S. Candidissima, the dominant acids are oleic, linoleic and palmitic acids.     

Absolute Antioxidant Activity of Five Phenol-Rich Essential Oils

Essential oils (EOs) have promising antioxidant activities which are gaining interest as natural alternatives to synthetic antioxidants in the food and cosmetic industries. However, quantitative data on chain-breaking activity and on the kinetics of peroxyl radical trapping are missing. Five phenol-rich EOs were analyzed by GC-MS and studied by oxygen-uptake kinetics in inhibited controlled autoxidations of reference substrates (cumene and squalene). Terpene-rich Thymus vulgaris (thymol 4%; carvacrol 33.9%), Origanum vulgare, (thymol 0.4%; carvacrol 66.2%) and Satureja hortensis, (thymol 1.7%; carvacrol 46.6%), had apparent k_inh (30 °C, PhCl) of (1.5 ± 0.3) × 10⁴, (1.3 ± 0.1) × 10⁴ and (1.1 ± 0.3) × 10⁴ M⁻¹s⁻¹, respectively, while phenylpropanoid-rich Eugenia caryophyllus (eugenol 80.8%) and Cinnamomum zeylanicum, (eugenol 81.4%) showed apparent k_inh (30 °C, PhCl) of (5.0 ± 0.1) × 10³ and (4.9 ± 0.3) × 10³ M⁻¹s⁻¹, respectively. All EOs already granted good antioxidant protection of cumene at a concentration of 1 ppm (1 mg/L), the duration being proportional to their phenolic content, which dictated their antioxidant behavior. They also afforded excellent protection of squalene after adjusting their concentration (100 mg/L) to account for the much higher oxidizability of this substrate. All investigated EOs had k_inh comparable to synthetic butylated hydroxytoluene (BHT) were are eligible to replace it in the protection of food or cosmetic products.     

Influence of fibre coating in headspace solid-phase microextraction-gas chromatographic analysis of aromatic and medicinal plants

Solid-phase microextraction (SPME) is a solvent-free technique, which is well established in headspace analysis since it is sensitive, because of the concentration factor achieved by the fibres, and selective, because of different coating materials which can be used. The performance of eight commercially available SPME fibres was compared to evaluate the recoveries of some characteristic components with different polarities and structures present in the headspace of four aromatic and medicinal plants: rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), thyme (Thymus vulgaris L.) and valerian (Valeriana officinalis L.). The relative concentration capacity of each fibre on the same components of each plant was also determined by comparing their abundance with that obtained by classical static-headspace GC. The partition coefficient, K1, between the headspace gaseous phase and SPME polymeric coating, and the relative concentration factors, of some of the characteristic components of the plant investigated dissolved in dibutyl phtalate, were also determined, under rigorously standardised analysis conditions. The results showed that the most effective fibres were those consisting of two components, i.e., a liquid phase (polydimethylsiloxane) and a porous solid (carboxen or divinylbenzene, or both).     

High-Performance Thin-Layer Chromatographic Quantification of Some Essential Oils from Anethum graveolens Extracts

JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatography (HPTLC) method has been established for the analysis of α-phellandrene and...     

Thymol bioactivity: A review focusing on practical applications

Thymol is a natural volatile monoterpenoid phenol that is the main active ingredient of oil extracted from species Thymus vulgaris L., commonly known as thyme, and other plants such as Ocimum gratissimum L., Origanum L., Carum copticum L., different species of the genus Satureja L., Oliveria decumbens Vent, and many others. It is a versatile molecule with a wide variety of practical applications such as medical, dentistry, veterinary, food, and agrochemicals, among others. Its pharmacological applications have been the most investigated and reported, focusing on its prominent antimicrobial, antioxidant, anti-inflammatory, cicatrizing activities. Furthermore, it is noteworthy that the research on its agricultural applications has increased, highlighting its uses as a natural agrochemical and preservative to safeguard foods from pathogenic microorganisms both in sowing and storage, which could have a beneficial effect on human health and the environment. Research has also been reported on its activity as an insecticide, acaricide, and animal repellent. This review summarizes important aspects of thymol such as its bioavailability, synthesis, and biological activities, with special interest in practical applications.     

The Impact of Selected Essential Oils Applied to Non-Woven Viscose on Bacteria That Cause Lower Urinary Tract Infections—Preliminary Studies

Inflammation of the lower urinary tract is a very common problem, which occurs particularly in women. A concept of a biotextronics system for preventive and support treatment of lower urinary tract inflammations was presented. The system includes a non-woven viscose insert for essential oils application. The oils were deposited on the non-woven viscose and incubated in the temperature of 37 °C and served a model for their action in the vapor phase as the element of the biotextronics system. The essential oils used in the research were the following: chamomile (Matricaria chamomilla L.), sage (Salvia officinalis L. and Salvia lavandulaefolia), juniper (Juniperus communis L.), thyme (Thymus vulgaris L.), and mixtures of chamomile oil with oils of each sage species in a 1:1 ratio. The oils were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Staphylococcus saprophyticus, and Enterococcus faecalis. The best inhibitory effect in vapor phase was noted for chamomile essential oil at the lowest concentration (0.054 µL/cm³). Both mixtures of chamomile and sage acted antagonistically, lowering the antibacterial activity of the individual oils applied solely. Juniper and Salvia officinalis essential oils at the concentrations tested increased the growth of at least one of the bacteria tested. Salvia lavandulaefolia Vahl. essential oil inhibited all bacteria, only at the concentration 0.214 µL/cm³. The thyme oil, at the concentration 0.054 µL/cm³, reduced the growth of all bacterial species tested. Chamomile and thyme essential oils were chosen for further research in the biotextronics pantiliner system.     

Determination of the Component Composition of Essential Oil of Thyme Species by the Method of Gas Chromatography

Abstract—A comparative study of the component composition of the essential oil of cultivars of Thymus serpyllum L. and similar kinds to expose marker connections for the authentication of raw material is conducted by the method of gas chromatography. In the essential oil of one of the specimen the propionates discovered are typical representatives of the Lamiaceae family.     

Heteroleptic Tin(II) Initiators for the Ring‐Opening (Co)Polymerization of Lactide and Trimethylene Carbonate: Mechanistic Insights from Experiments and Computations

The tin(II) complexes {LO^x}Sn(X) ({LO^x}^?=aminophenolate ancillary) containing amido ( 1 – 4 ), chloro ( 5 ), or lactyl ( 6 ) coligands (X) promote the ring‐opening polymerization (ROP) of cyclic esters. Complex 6 , which models the first insertion of L ‐lactide, initiates the living ROP of L ‐LA on its own, but the amido derivatives 1 – 4 require the addition of alcohol to do so. Upon addition of one to ten equivalents of iPrOH, precatalysts 1 – 4 promote the ROP of trimethylene carbonate (TMC); yet, hardly any activity is observed if tert‐butyl (R)‐lactate is used instead of iPrOH. Strong inhibition of the reactivity of TMC is also detected for the simultaneous copolymerization of L ‐LA and TMC, or for the block copolymerization of TMC after that of L ‐LA. Experimental and computational data for the {LO^x}Sn(OR) complexes (OR=lactyl or lactidyl) replicating the active species during the tin(II)‐mediated ROP of L ‐LA demonstrate that the formation of a five‐membered chelate is largely favored over that of an eight‐membered one, and that it constitutes the resting state of the catalyst during this (co)polymerization. Comprehensive DFT calculations show that, out of the four possible monomer insertion sequences during simultaneous copolymerization of L ‐LA and TMC: 1) TMC then TMC, 2) TMC then L ‐LA, 3) L ‐LA then L ‐LA, and 4) L ‐LA then TMC, the first three are possible. By contrast, insertion of L ‐LA followed by that of TMC (i.e., insertion sequence 4) is endothermic by +1.1 kcal mol^?1, which compares unfavorably with consecutive insertions of two L ‐LA units (i.e., insertion sequence 3) (?10.2 kcal mol^?1). The copolymerization of L ‐LA and TMC thus proceeds under thermodynamic control.     

Essential Oils of Seven Lamiaceae Plants and Their Antioxidant Capacity

Oxidative stress has been reported as a cause of many diseases like Parkinson′s, Alzheimer′s, cardiovascular disease, and diabetes. Oxidative stress can also lead to cancer formation by promoting tumor development and progression. Antioxidants derived from Lamiaceae plants play an important role in natural medicine, pharmacology, cosmetology, and aromatherapy. Herein, we examine the antioxidative capacity of essential oils from seven aromatic Lamiaceae plants against the synthetic radicals DPPH and ABTS. Among the essential oils analyzed, the most robust scavenging capacities were found in mixtures of volatile compounds from thyme and savory. The scavenging activity of tested EOs against the ABTS radical was clearly higher than activity towards DPPH. Analysis of essential oils with weaker antioxidant activity has shown that volatile compounds from marjoram, sage, and hyssop were more active than EOs from lavender and mint. It can be suggested that the potent antioxidant capacity of thyme (Thymus vulgaris) and savory (Satyreja hortensis) are related to a high level of phenolic constituents, such as thymol and carvacrol. On the other hand, the elevated antioxidative power of marjoram, sage, and hyssop essential oils may also be due to their terpinene, o-cymene, terpinolene, and terpinen-4-ol constituents. Although non-phenolic components are less active than thymol or carvacrol, they may affect antioxidant capacity synergistically.     

Phytochemical analysis of the essential oil of Thymus serpyllum L. growing wild in Estonia

Variations in the essential oil composition of Thymus serpyllum L., growing wild in Estonia (33 samples) and in some other countries (Russia, Latvia and Armenia, seven samples) were determined. The oil were obtained from Estonia (46 samples) in yields 0.6-4.4 and 1.9-8.2 mL kg(-1) in other countries. The T. serpyllum herb grown in Estonia usually did not confirmed to the EP standard in the aspect of the essential oil contents (3.0 mL kg(-1)). Variations in the essential oil composition of wild thyme were studied using capillary gas chromatographic methods. A total of 94 components were identified. Thymol and carvacrol, mentioned in literature as principial components, are not the main components of the essential oil of wild thyme growing in Estonia. (E)-nerolidol, caryophyllene oxide, myrcene and borneol chemotypes of wild thyme drug are distinguishable. The chemical composition of samples from Russia, Latvia and Armenia is very variable.     

Biological Activity of Essential Oils of Four Juniper Species and Their Potential as Biopesticides

The objective of this study was to assess the biological activity of essential oils (EOs) of four Juniperus species obtained via two different distillation methods and their potential as biopesticides. The studied factors were juniper species (Juniperus communis L., J. oxycedrus L., J. pygmaea C. Koch., and J. sibirica Burgsd), plant sex (male (M) and female (F)), and distillation method (hydrodistillation via a standard Clevenger apparatus (ClevA) and semi-commercial (SCom) steam distillation). The hypothesis was that the EO will have differential antioxidant, antimicrobial, and insecticidal activities as a function of plant species, plant sex, and distillation method. The two distillation methods resulted in similar EO composition within a given species. However, there were differences in the EO content (yield) due to the sex of the plant, and also differences in the proportions of some EO components. The concentration of α-pinene, β-caryophyllene, δ-cadinene and δ-cadinol was dissimilar between the EO of M and F plants within all four species. Additionally, M and F plants of J. pygmaea, and J. sibirica had significantly different concentrations of sabinene within the respective species. The EOs obtained via ClevA extraction showed higher antioxidant capacity within a species compared with those from SCom extraction. All of the tested EOs had significant repellent and insecticidal activity against the two aphid species Rhopalosiphum padi (bird cherry-oat aphid) and Sitobion avenae (English grain aphid) at concentrations of the EO in the solution of 1%, 2.5%, and 5%. The tested EOs demonstrated moderate activity against selected pathogens Fusarium spp., Botrytis cinerea, Colletotrichum spp., Rhizoctonia solani and Cylindrocarpon pauciseptatum. The results demonstrate that the standard ClevA would provide comparable EO content and composition in comparison with SCom steam distillation; however, even slight differences in the EO composition may translate into differential bioactivity.