Johannes Novak

Chemical composition and antimicrobial activity of Cymbopogon citratus and Cymbopogon giganteus essential oils alone and in combination.

As part of ongoing research on the chemical composition and the antimicrobial properties of Burkinabe plants essential oils alone and in combination, essential oils (EOs) from leaves of Cymbopogon citratus and Cymbopogon giganteus from Burkina Faso were analyzed by GC-FID and GC-MS. Five constituents, which accounted for 96.3% of the oil, were identified in the EO of C. citratus. Geranial (48.1%), neral (34.6%) and myrcene (11.0%) were the major constituents. For C. giganteus a total of eight compounds were identified which represented 86.0% of the oils extracted. The dominant compounds were limonene (42%) and a set of monoterpene alcohols: trans-p-mentha-1(7),8-dien-2-ol (14.2%), cis-p-mentha-1(7),8-dien-2-ol (12%), trans-p-mentha-2,8-dien-1-ol (5.6%) and cis-p-mentha-2,8-dien-1-ol (5.2%). The EOs were tested against nine bacteria by using disc diffusion and microdilution methods. C. giganteus EO showed antimicrobial effects against all microorganisms tested whereas C. citratus EO failed to inhibit Pseudomonas aeruginosa. The antimicrobial activity of combinations of the two EOs was quantified by the checkerboard method. Combinations of the two EOs exerted synergistic, additive and indifferent antimicrobial effects. Results of the present investigation provide evidence that the combinations of plant EOs could be assessed for synergistic activity in order to reduce their minimum effective dose.

Diversity of essential oil glands of clary sage (Salvia sclarea L., Lamiaceae)

The Lamiaceae is rich in aromatic plant species. Most of these species produce and store essential oils in specialised epidermal oil glands, which are responsible for their specific flavour. Two types of glands producing essential oil and possessing different morphological structure can be found in Salvia sclarea: peltate and capitate glands. The content of single oil glands from different positions on the plant (corolla, calyx and leaf) were sampled using an SPME fibre and analysed by gas chromatography in order to study variability of the essential oil composition. It was found that the composition of terpenoids is quite variable within an individual plant. Capitate oil glands mainly produce three essential oil compounds: the monoterpenes linalool and linalyl acetate, and the diterpene sclareol. Peltate oil glands, however, accumulate noticeable concentrations of sesquiterpenes and an unknown compound (m/z = 354). Furthermore, the oil composition varies within each gland type according to the plant organ. Linalool and linalyl acetate are characteristic substances of flowers, whereas the sesquiterpenes occur in higher proportions in leaves. Even within one gland type on a single leaf, the chemical variability is exceedingly high.

Botanical species being used for manufacturing plant food supplements (PFS) and related products in the EU member states and selected third countries.

A great wealth of plants and plant derived preparations are used in the intention to supplement the basic nutrition in order to sustain and promote health. They may be used directly or consumed as manufactured plant food supplements (PFS) in dosed form. The use of these plants may already have a long tradition as fruit, vegetable or (folk) medicinal plants. Due to globalisation, more and more plants originating from all over the world are now offered and marketed in European countries, including species from China, South Africa and the American continent. For reasons of security, EU wide lists of plants accepted or prohibited to be used in food supplements are in elaboration. A crucial point is the correct identification of the plant material. The identity can be assessed by morphological, chemical and DNA specific methods. The active substances usable in PFS are secondary plant products that are often characteristic for certain plant groups (taxa), species or plant parts. They comprise not only polyphenols, essential oils, carotenoids and phytosterols, but also glucosinolates or saponins. The quality of the plant material used for PFS depends on a variety of factors, including the natural phytochemical, intraspecific variation with the occurrence of chemotypes, the ontogenetic variation, the considered plant parts and environmental influences during plant growth. In the production of the raw materials for PFS international standards (good agricultural practice, fair trade) should be applied.

Polyacetylenes from Radix et Rhizoma Notopterygii Incisi with an Inhibitory Effect on Nitric Oxide Production In Vitro

Notopterygium roots (Qiang Huo) have been used in traditional Chinese medicine for treating colds, inflammatory diseases like rheumatoid arthritis, and as an analgesic. The anti-inflammatory activity of the roots of Notopterygium incisum has been evaluated by testing the inhibitory activity on nitric oxide production by inducible nitric oxide synthase. The apparent authenticity of the sample was checked by DNA sequence comparison. Using activity-guided isolation, different compounds were isolated and structurally characterized by means of NMR and mass spectroscopy. Eight polyacetylenes could be identified and were tested on their inhibitory activity on nitric oxide production in RAW 264.7 mouse macrophages using the Griess assay. Different 3-hydroxy allyl polyacetylenes exhibited significant activity (IC50: 8-acetoxyfalcarinol, 20.1 µM; falcarindiol, 9.2 µM; 9-epoxyfalcarindiol, 8.8 µM; and crithmumdiol, 23.6 µM).

Temperature Influences Thymol and Carvacrol Differentially in Origanum spp. (Lamiaceae)

Abstract The composition of secondary metabolites is often modified by environment and ontogenesis. To explicitly study the Influence of temperature on essential oil compositions, experiments on a hybrid of Origanum vulgare x Origanum majorana (containing both major monoterpene pathways of the genus Origanum, ‘sabinyl’ and ‘cymyl’-pathway) and on Origanum syriacum ssp. syriacum (only ‘cymyl’-pathway) were conducted in growth chambers. Clonally propagated plants were grown at three different temperature levels and the solvent extracts analyzed by GC/MS for their composition of essential oil compounds. The major ‘sabinyl’ compound cis-sabinene hydrate was not influenced by temperature, while temperature significantly influenced thymol and carvacrol and other essential oil compounds. Although thymol and carvacrol are closely related monoterpene phenols, they reacted to varying levels of temperature in an opposite way. Thymol increased with decreasing temperatures while carvacrol increased with increasing temperatures.

Essential oil composition and antioxidant activity of Stachys sylvatica L. (Lamiaceae) from different wild populations in Kosovo

Leaves and inflorescences of Stachys sylvatica L. (Lamiaceae) were collected from three different wild populations in Kosovo to study the natural variation of the chemical composition of essential oils, total flavonoids, total phenolics and the antioxidant activity. Essential oils were obtained by steam distillation and analysed by GC-FID and GC–MS, whereas total flavonoids, total phenolics and antioxidant activities were determined by spectrophotometric methods. Yields of essential oils ranged from 0.001% to 0.007% (v per dry weight). Twenty-eight volatile constituents were identified. The main constituents were α-pinene, β-pinene and germacrene-D. Total phenolics ranged from 39.3 to 70.8 mg g−1 dry mass, whereas total flavonoid content ranged from 30.44 to 70.63 mg g−1 dm. The antioxidant activity, as measured by the DPPH method, exhibited a rather high degree of activity ranging from 25.5% to 57.2%, whereas the FRAP antioxidant activity showed a lower variability and ranged from 93 to 133.4 mg g−1 dm.

Volatile fraction differences for Lamiaceae species using different extraction methodologies

To achieve a detailed chemical characterization and to find the changes in the composition the volatiles of Lavandula latifolia, Salvia lavandulifolia and Thymus mastichina were analyzed through GC-FID/MS and a total of 47, 48 and 48 compounds were identified, respectively. 1,8-cineol+limonene was the main compound in the three species. Three extracting methodologies were used: hydrodistillation (HD), microdistillation (MD) and dichloromethane extraction (EX). The amount of volatile compounds was affected by the kind of method used and by the kind of species analyzed, thus, S. lavandulifolia produced a higher amount of volatiles with the EX and T. mastichina with MD. HD showed significantly lower amount of volatiles for the three species. With HD and MD a higher amount of β-pinene was obtained. MD produced a higher proportion of 1,8-cineol+limonene. Canonical discrimination function was done using the two most predictable compounds to distinguish among techniques revealing the method used for each species.

Chemical Composition of Juniperus communis L. Cone Essential Oil and Its Variability among Wild Populations in Kosovo.

Ripe cones of Juniperus communis L. (Cupressaceae) were collected from five wild populations in Kosovo, with the aim of investigating the chemical composition and natural variation of essential oils between and within wild populations. Ripe cones were collected, air dried, crushed, and the essential oils obtained by hydrodistillation. The essential‐oil constituents were identified by GC‐FID and GC/MS analyses. The yield of essential oil differed depending on the population origins and ranged from 0.4 to 3.8% (v/w, based on the dry weight). In total, 42 compounds were identified in the essential oils of all populations. The principal components of the cone‐essential oils were α‐pinene, followed by β‐myrcene, sabinene, and D‐limonene. Taking into consideration the yield and chemical composition, the essential oil originating from various collection sites in Kosovo fulfilled the minimum requirements for J. communis essential oils of the European Pharmacopoeia. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were used to determine the influence of the geographical variations on the essential‐oil composition. These statistical analyses suggested that the clustering of populations was not related to their geographic location, but rather appeared to be linked to local selective forces acting on the chemotype diversity.

Comparative analysis of the essential oils of Valeriana hardwickii Wall. from Vietnam and Valeriana officinalis L. from Austria

The volatile compounds from roots, stems, and leaves of Valeriana hardwickii and Valeriana officinalis were obtained by microdistillation and analyzed by gas chromatography–flame ionization detector (GC–FID) and gas chromatography–mass spectometry (GC–MS). In V. hardwickii, sixty-two, thirty-one, and thirty-one components were identified representing 90, 90, and 92% of total oil in the roots, stems, and leaves, respectively. The major compounds in the root oil were camphene (12.9%), bornyl acetate (17.6%), and maaliol (10.6%), while borneol (6.2%), trans-anethole (32.7%), and maaliol (6.3%) were the dominant components in the stem oil and camphene (12.6%), bornyl acetate (15.0%), and hexahydrofarnesyl acetone (9.2%) were the principal components in the leaf oil. In V. officinalis, bornyl acetate (7.8%), δ-elemene (9.3%), and valerenal (14.7%) were the dominant components in the roots among fifty-four compounds identified which accounted for 80% of the total oil. In contrast to V. hardwickii, the stems and roots of V. officinalis contained very small amounts of essential oil and consequently, only a few compounds were identified in the leaves and none could be detected in the stems.

Arnica montana subsp. atlantica: Really a subspecies?

In Arnica montana L. (Asteraceae) two subspecies are described, A. montana subsp. atlantica (AMA), present only on the Iberian Peninsula and A. montana subsp. montana (AMM) with a very wide distribution area. The morphological differences between the two subspecies are small and variable. Therefore, this concept is sometimes questioned. To establish the genetic background of the two subspecies, populations of AMA and AMM together with herbarium samples and DNA Bank material of AMM were tested with 12 microsatellite markers. A. montana propagates by seeds or by clonal propagation of its rhizome. In AMA, clonality was frequent while in AMM only one case of clonality could be identified. Therefore, further results were clone-corrected. Genetically, AMA separated very well from AMM with a GST between the subspecies of 0.81, genetically justifying the subspecies concept of A. montana. Genetic variability in AMA (Hexp = 0.28) was lower than in the AMM populations (Hexp = 0.70). A somewhat higher fixation index of AMA (FST = 0.17, compared to an FST = 0.08 for AMM) may indicate that geneflow in AMA is a bit more restricted than in alpine AMM. However, the fixation index of AMA is not deviating from Hardy–Weinberg equilibrium. No inbreeding was observed for AMA (FIS = 0.10) and AMM (FIS = 0.08).