Brigitte Lukas

Oregano: a source for peroxisome proliferator-activated receptor gamma antagonists.

Peroxisome proliferator-activated receptors (PPARs) are drug targets for several perturbations of metabolic syndrome, defined as the coexistence of obesity, hyperglycemia, hypertension, and hyper/dyslipidemia. In this study, PPAR activation by oregano (e.g., Origanum vulgare) and its components was tested. Oregano extracts bind but do not transactivate PPARgamma, and binding affinity differs among different oregano extracts. The extracts contain PPARgamma antagonists (e.g., quercetin, luteolin, rosmarinic acid, and diosmetin), selective PPARgamma modulators (e.g., naringenin and apigenin), and PPARgamma agonists (e.g., biochanin A). Oregano extract and isolated compounds in the extract antagonize rosiglitazone-mediated DRIP205/TRAP220 recruitment to PPARgamma, pointing to oregano extracts as putative food supplements for weight reduction. Rosmarinic acid and biochanin A, PPARalpha agonists, may ameliorate the lipid profile. By endothelial nitric oxide synthase activation, oregano extract could prevent atherosclerosis. The results warrant further investigation of oregano extract for its potential to prevent and ameliorate metabolic syndrome and its complications.

A Strategy to Setup Codominant Microsatellite Analysis for High-Resolution-Melting-Curve-Analysis (HRM)

BackgroundHigh resolution melting curve analysis (HRM) is a technique that measures exactly the decreasing fluorescence of intercalating dye in the process of dissociation of double stranded DNA. The measurement is immediately following PCR in a one-step, closed-tube method. The shape of the melting curve depends on the GC content, length and sequence of the amplicon. Hence it is a powerful, fast and cheap method to detect Single Nucleotide Polymorphisms (SNPs) and other mutations.ResultsHere we present a strategy to set up microsatellite analysis for HRM including the correct assignment of heterozygous samples by comparative analysis and artificial mixtures of samples. The approach is demonstrated on two Simple Sequence Repeat (SSR) loci of different complexity in the genus Origanum. Following this strategy all alleles of our sample sets could be classified correctly.ConclusionHRM can be used in microsatellite analysis and other codominant marker systems implementing a protocol of comparative melting curve assignment with artificial mixtures of samples to overcome difficulties in correctly assigning heterozygous samples. The method is faster, more sensitive and cheaper than standard protocols for microsatellite analysis.

Composition of essential oil compounds from different Syrian populations of Origanum syriacum L. (Lamiaceae).

The chemical compositions of the essential oil compounds of 117 individual plants belonging to 11 Syrian populations of Origanum syriacum L. (Lamiaceae) were studied by GC-FID and GC-MS. The composition was dominated by carvacrol and/or thymol with a high degree of polymorphism in the occurrence of these two compounds between the different populations. In three populations carvacrol was dominating, with thymol being present only in minor amounts, whereas in only one population thymol was the main compound, with carvacrol only in traces. In all other populations both carvacrol and thymol were present as major compounds. No geographical pattern could be detected for the occurrence of the chemotypes. Thymoquinone, a promising anticancer candidate, was present in the extracts in a wide range between 0.04 and 23.7%.

Identification and characterization of simple sequence repeat markers from a glandular Origanum vulgare expressed sequence tag

Oregano (Origanum vulgare) and marjoram (Origanum majorana) are two sensorial distinct spices within the genus Origanum (Lamiaceae). Simple sequence repeat (SSR) markers were developed from expressed sequence tags (ESTs) of essential oil glands of O. vulgare. Thirteen EST‐SSR loci were evaluated using 20 individual plants of O. vulgare and 19 plants of Origanum majorana. The number of alleles per locus ranged from one to four. All loci developed from O. vulgare successfully cross‐amplified in O. majorana.

Identification of Verbena officinalis Based on ITS Sequence Analysis and RAPD-Derived Molecular Markers

Verbenae herba is a widely used drug and consists of the aerial parts of Verbena officinalis (Verbenaceae). Until now, the identification has been performed based on morphological and phytochemical analyses, which are not reliable enough to distinguish Verbena officinalis from other relevant species of the genus Verbena. Hence, impurities and adulterants, negatively influencing the therapeutic effect of the drug, may remain undetected. In an attempt to generate an accurate authentication method we used two different DNA-based approaches: comparison of ITS sequences and molecular markers (RAPD). Both approaches generally enabled discrimination of V. officinalis from the rest of the genus despite the intraspecific variation existing within V. officinalis. The application of the two independent methods, supporting each other, increases the security of identification. For better reproducibility and faster analysis, however, a SCAR marker and primers for HRM were derived from the RAPD results. The SCAR marker could distinguish V. officinalis from all other verbena species except its closest relative V. hastata, while discrimination of V. officinalis even from V. hastata was unproblematic with HRM.

Validation of a quantitative assay of arbutin using gas chromatography in Origanum majorana and Arctostaphylos uva-ursi extracts

INTRODUCTION Arbutin is a skin-whitening agent that occurs naturally in the bark and leaves of various plants. It is commonly quantified in plant extracts and skin-whitening products by HPLC. OBJECTIVE To develop an alternative gas chromatographic method for the separation and quantification of arbutin in Origanum majorana and Arctostaphylos uva-ursi extracts. METHODOLOGY N,O-Bis(trimethylsilyl)acetamide and trimethylchlorosilane were used as silylation reagents, and the gas chromatographic separation of silylated extracts and standards was performed using a DB-5 narrow bore column. GC-MS was used for the compound identification, and the quantification was carried out by GC-FID. The quantitative results were compared with those of HPLC analysis. RESULTS The developed method gave a good sensitivity with linearity in the range 0.33-500 mg/mL and recovery >98%, allowing the quantification of arbutin in O. majorana and A. uva-ursi extracts. The relative standard deviations (RSD) relating to intra-day and inter-day precision were <0.002% and <4.8%, respectively. The GC results correlated well with those obtained by HPLC analysis. CONCLUSION The analysis of marjoram and bearberry samples showed that the established GC method was rapid, selective, and demonstrated that arbutin could be screened alternatively by gas chromatography.

The Essential Oil Composition of Wild Growing Sweet Marjoram (Origanum majorana L., Lamiaceae) from Cyprus -Three Chemotypes

Abstract Individual plants grown in a greenhouse from seeds of a natural population of sweet marjoram (Origanum majorana L.) from Cyprus were analyzed for their essential oil composition. Three chemotypes were detected in the population. Besides the standard ‘marjoramy’ composition (‘sabinyl chemotype’) with 74% of oil compounds belonging to the bicyclic compounds sabinene, trans- and cis-sabinene hydrate and cis-sabinene hydrate acetate (‘sabinyl compounds’), two further chemotypes were present in the population, namely a pure α—terpineol chemotype (73% α—terpineol) and a mixed sabinyl/α—terpineol chemotype (41% sabinyl compounds, 40% α—terpineol). The chemotype frequencies found in this population were 56% of the plants belonging to the sabinyl chemotype, 4% to the pure α—terpineol chemotype and 40% to the mixed sabinyl/α—terpineol chemotype.

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.

DNA-Based Identification of Calendula officinalis (Asteraceae)

Premise of the study: For the economically important species Calendula officinalis, a fast identification assay based on high-resolution melting curve analysis was designed. This assay was developed to distinguish C. officinalis from other species of the genus and other Asteraceae genera, and to detect C. officinalis as an adulterant of saffron samples. Methods and Results: For this study, five markers (ITS, rbcL, 5′ trnK-matK, psbA-trnH, trnL-trnF) of 10 Calendula species were sequenced and analyzed for species-specific mutations. With the application of two developed primer pairs located in the trnK 5′ intron and trnL-trnF, C. officinalis could be distinguished from other species of the genus and all outgroup samples tested. Adulterations of Calendula DNA in saffron could be detected down to 0.01%. Conclusions: With the developed assay, C. officinalis can be reliably identified and admixtures of this species as adulterant of saffron can be revealed at low levels.

Phytogenic pigments in animal nutrition: potentials and risks.

Phytogenic pigments are secondary plant compounds responsible for coloring effects in plant tissues. In particular, phenolic flavonoids and terpenoid carotenoids, but also rare compounds like curcumin and betalain, form this group of biochemical agents used in animal nutrition. From the perspective of ecological mutuality between plants and animals, these compounds are of crucial importance because they serve as visual attraction for herbivores but also signal nutritional and/or health-promoting values. This review focuses on the properties of phytogenic pigments which are likely to impact feed intake and preferences of livestock. Also natural prophylactic and/or therapeutic properties and, in particular, the potential of pigments to enhance quality and health value of animal products for human consumption are important issues. Nevertheless, reasonable limits of use due to possible adverse indications have been suggested recently. Pathways of digestion, metabolism and excretion in animals play a crucial role not only in the evaluation of effectiveness but also in the prediction of potential risks for human consumption. The popularity of natural feed additives is growing; therefore, more research work is needed to better understand metabolic pathways in the animals body and to better estimate the potentials and risks of pigmenting plant compounds used in animal nutrition.