Erica G. Wilson

Metabolic classification of South American Ilex species by NMR-based metabolomics.

The genus Ilex to which mate (Ilex paraguariensis) belongs, consists of more than 500 species. A wide range of metabolites including saponins and phenylpropanoids has been reported from Ilex species. However, despite the previous works on the Ilex metabolites, the metabolic similarities between species which can be used for chemotaxonomy of the species are not clear yet. In this study, nuclear magnetic resonance (NMR) spectroscopy-based metabolomics was applied to the classification of 11 South American Ilex species, namely, Ilex argentina, Ilex brasiliensis, Ilex brevicuspis, Ilex dumosa var. dumosa, I. dumosa var. guaranina, Ilex integerrima, Ilex microdonta, I. paraguariensis var. paraguariensis, Ilex pseudobuxus, Ilex taubertiana, and Ilex theezans. (1)H NMR combined with principal component analysis (PCA), partial least square-discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA) showed a clear separation between species and resulted in four groups based on metabolomic similarities. The signal congestion of (1)H NMR spectra was overcome by the implementation of two-dimensional (2D)-J-resolved and heteronuclear single quantum coherence (HSQC). From the results obtained by 1D- and 2D-NMR-based metabolomics it was concluded that species included in group A (I. paraguariensis) were metabolically characterized by a higher amount of xanthines, and phenolics including phenylpropanoids and flavonoids; group B (I. dumosa var. dumosa and I. dumosa var. guaranina) with oleanane type saponins; group C (I. brasiliensis, I. integerrima, I. pseudobuxus and I. theezans) with arbutin and dicaffeoylquinic acids, and group D (I. argentina, I. brevicuspis, I. microdonta and I. taubertiana) with the highest level of ursane-type saponins. Clear metabolomic discrimination of Ilex species and varieties in this study makes the chemotaxonomic classification of Ilex species possible.

Extraction for Metabolomics: Access to The Metabolome

INTRODUCTION The value of information obtained from a metabolomic study depends on how much of the metabolome is present in analysed samples. Thus, only a comprehensive and reproducible extraction method will provide reliable data because the metabolites that will be measured are those that were extracted and all conclusions will be built around this information. OBJECTIVE To discuss the efficiency and reliability of available sample pre-treatment methods and their application in different fields of metabolomics. METHODS The review has three sections: the first deals with pre-extraction techniques, the second discusses the choice of extraction solvents and their main features and the third includes a brief description of the most used extraction techniques: microwave-assisted extraction, solid-phase extraction, supercritical fluid extraction, Soxhlet and a new method developed in our laboratory--the comprehensive extraction method. RESULTS Examination of over 200 studies showed that sample collection, homogenisation, grinding and storage could affect the yield and reproducibility of results. They also revealed that apart from the solvent used for extraction, the extraction techniques have a decisive role on the metabolites available for analysis. CONCLUSION It is essential to evaluate efficacy and reproducibility of sample pre-treatment as a first step to ensure the reliability of a metabolomic study. Among the reviewed methods, the comprehensive extraction method appears to provide a promising approach for extracting diverse types of metabolites.

Metabolomics: a tool for anticancer lead-finding from natural products.

Natural products have been the source of many drugs used in modern therapeutics, and particularly in the case of anticancer drugs, more than 50 % originally came from natural products. Their importance as a source of leads for new drugs therefore cannot be underestimated. However, due to the painstaking way of conventional lead-finding, the attention towards natural products has been deviated in the last decades. A new strategy for the detection of active compounds is necessary to get natural product research out of its stalemate. Metabolomics, with its holistic approach and the possibility it provides for the simultaneous detection of all sorts of metabolites, has the potential to be instrumental for this new approach. Therefore, this review aims at providing examples that illustrate the possibilities of using metabolomics as a tool to find active compounds from natural products, specifically anticancer drugs. Two different methods, IN SILICO and IN SITU, have been introduced as possible approaches. Current methods to detect anticancer activity in natural products have been briefly reviewed and compared in the first section, and various applications of metabolomics in cancer research are mentioned as they can provide comprehensive information of cancer metabolites utilized in the IN SITU approach. Metabolomics will certainly improve the efficiency of lead-finding from natural products and thus reinstate this prolific source of potential anticancer drugs.

Identification of possible compounds possessing adenosine A1 receptor binding activity in the leaves of orthosiphon stamineus using TLC and multivariate data analysis

Abstract A novel approach to identify compounds possessing adenosine A1 receptor binding activity in the leaves of O. stamineus was developed. O. stamineus extract is one of the components of a functional beverage used in Indonesia for the treatment of kidney stones. In this study, adenosine A1 receptor binding, which is related to the diuretic action in the treatment of kidney stones was tested. A combination of thin layer chromatography of different extracts prepared by extraction with diverse solvents (n-hexane, chloroform, n-butanol and water), and multivariate data analysis based on orthogonal partial least squares proved to be a promising approach to determine these active compounds. Several methoxyflavonoids, fatty acids or terpenoids were estimated to be related to this activity. The results of this study support the traditional use in Indonesia of O. stamineus as a functional drink to treat kidney stones.

Investigation of Chemomarkers of Astragali Radix of Different Ages and Geographical Origin by NMR Profiling

Astragalus roots from Astragalus membranaceus Bunge or Astragalus membranaceus var. mongholicus (Bunge) Hsiao are among the most popular traditional medicinal plants due to their diverse therapeutic uses based on their tonic, antinephritic, immunostimulant, hepatoprotectant, diuretic, antidiabetic, analgesic, expectorant and sedative properties. Currently, the herb is produced or cultivated in various sites, including 10 different locations in China with very diverse environmental conditions. These differences affect their metabolic pools and consequently their medicinal properties. The comparative metabolic profiling of plants of different geographical origins or ages could contribute to detect biomarkers for their quality control and thus guarantee the efficacy of the herbal medicines produced with this drug. In this paper nuclear magnetic resonance spectroscopy (NMR)-based metabolomics was applied for to plants of different origins and age for this purpose. The results of this study show that in the set of samples evaluated, age is more discriminating than geographical location. The quantity of individual flavonoids and some primary metabolites contributed most to this age differentiation. On the other hand, based on the analysis of orthogonal partial least square (OPLS) modeling, the marker metabolites for the geographical origin were saponins and isoflavonoids.

High Performance Liquid Chromatographic Method for Iso‐α‐Acids

Abstract Using pure trans/cis‐isocohumulone, trans/cis‐isohumulone, and trans/cis‐isoadhumulone an isocratic HPLC system has been developed for quantitation of these compounds in hop extracts and beers. The mobile phase contains acetonitrile‐water‐ H3PO4 (50∶50∶0.01, v/v/v) and is used with a Phenomenex Hypersil 5 µ C18 column 250×4.6 mm, flow rate 1.5 mL/min. Baseline separation of all 6 isomers was achieved with a total run time of 25 min. The UV spectrum of these pure compounds using this system are quite different. The effect of different mobile phase compositions on separation was investigated as well as the chromatographic parameters, detection limit, and linearity.