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A new combined gas chromatography and mass spectrometry (GC-MS) method has been developed suitable for the urine sample treatment in aqueous phase with ethyl chloroformate (ECF) derivatization agents. The method has been extensively optimized and validated over a broad range of different compounds and urine samples. Analysis of test metabolite derivatives, containing spiked standards, or rat urine exhibited acceptable linearity, satisfactory intra-batch precision (repeatability) and stability, relative standard deviations (R.S.D.) less than 10 and 15% within 48 h, respectively. The quantification limits were 150-300 pg on column for most metabolites. Recovery of several representative compounds, at different concentrations, ranged from 70 to 120%, with R.S.D. better than 10% for rat urine. We were able to generally eliminate potentially confounding variables such as medium complexity, different urea concentrations, and/or derivatization procedure variability. Metabonomic profiling of 1,2-dimethylhydrazine (DMH)-induced precancerous colon rat urine using GC-MS with ECF derivatization was performed to evaluate the proposed method. The analytical variation of the method was smaller than the biological variation in the rat urine samples, proving the suitability of the method to analyze differences in the metabonome of a living system with perturbed metabolic network. Thus, the proposed GC-MS analytical method is reliable to analyze a large variety of metabolites and can be used to investigate human pathology including disease onset, progression, and mortality.

Abstract:The morphological appearance and some ingredients of Panax ginseng, Panax notoginseng and Panax japonicus of the Panax genus are similar. However, their pharmacological activities are obviously different due to the significant differences in the types and quantity of saponins in each herb. In the present study, ultra-performance liquid chromatography-quadrupole time-offlight mass spectrometry (UPLC-QTOFMS) was used to profile the abundances of metabolites in the three medicinal Panax herbs. Multivariate statistical analysis technique, that is, principle component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to discriminate between the Panax samples. PCA of the analytical data showed a clear separation of compositions among the three medicinal herbs. The critical markers such as chikusetsusaponin IVa, ginsenoside R0, ginsenoside Rc, ginsenoside Rb1, ginsenoside Rb2 and ginsenoside Rg2 accountable for such variations were identified through the corresponding loading weights, and the tentative identification of biomarkers is completed by the accurate mass of TOFMS and high resolution and high retention time reproducibility performed by UPLC. The proposed analytical method coupled with multivariate statistical analysis is reliable to analyze a group of metabolites present in the herbal extracts and other natural products. This method can be further utilized to evaluate chemical components obtained from different plants and/or the plants of different geographical locations, thereby classifying the medicinal plant resources and potentially elucidating the mechanism of inherent phytochemical diversity. Article:INTRODUCTION It is estimated that about 65-80% of the world's population is using traditional medicine as the primary form of healthcare (Akerele 1992). Traditional Chinese medicines (TCMs) are gaining more and more attention in many fields because of their low toxicity and good therapeutic performance. The quality and contents of herbs are highly variable depending on geographical origins, climate, cultivation, and the growth stage when harvested (Mahady et al. 2001). The profiling of natural products requires an analytical system capable of generating an information rich data set and needs to identify the compounds of interest, compare different batches of material to be compared and contrasted and isolate the compounds of interest from bulk solution. However, because of the chemical diversity of the metabolome, which for any given multicellular species comprises a mixture of thousands of compounds differing in size, polarity etc., and varying in abundance by several orders of magnitude, the need for multiparallel analytical techniques is obvious and well-accepted (Goodacre et al. 2004;Hall 2006). A number of techniques including nuclear magnetic resonance (NMR), liquid chromatography (LC) or gas chromatography (GC) coupled with mass spectrometry (MS) have been employed for metabolite profiling (Fiehn et al. 2000;Want et al. 2005;Fukusaki et al. 2006;Nordstrom et al...

Community participation is crucial for successful heritage tourism and community development. Levels and ways of participation vary, depending on nature and context of heritage sites. This paper explores community participation in tourism at Mutianyu Great Wall, China. General positive perceptions toward World Heritage, tourism development and tourism impacts are held by different groups of the local community. Between-group differences indicate that local opinions are influenced by different levels of impacts from and participation in tourism. Community members receive benefits with minimal participation in decision making. This study provokes reflections on community participation theory and management practices in the Chinese context.

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