The Assessment of Plant Metabolite Profiles by NMR-Based Methodologies

Abstract

IntroductionPlants, plant-derived products and plant-derived chemicals serve mankind as medicines, nutraceuticals, functional foods, poisons, fragrances, and staple foods [1], [2]. Any of the utilised plant materials show characteristic profiles of low molecular weight biomolecules, often summarised as ªmetabolitesº. Most of the observed bioactivities can be correlated to certain metabolites or to metabolite groups. Abiotic environmental factors such as UV radiation, temperature, or moisture and biotic factors such as xenobiotics (e. g., toxins, pesticides, pharmaceuticals), nutritional sources (e. g., limited nitrogen or carbon sources, salt stress, starvation), progressing diseases, organism development, or genetic modifications lead to very specific qualitative and quantitative shifts in metabolite patterns. Detecting and identifying pattern changes from normal to anomalous is the first and often crucial step in understanding underlying biochemical changes (e. g., genetic disorders, silent mutations, intoxication) of the organism. In the case of authentication and quality control of biological materials used as food, herbal medicinal products or nutraceuticals, changes of metabolite profiles can be associated with factors like adulteration or spoilage. Here, reliable discrimination between properly treated materials and altered samples is mandatory. Hence, analytes identified as discriminators by the use of unbiased approaches and multivariate statistical methods might serve as diagnostic markers for further routine analysis [3]. Abstract NMR-based metabolic profiling techniques can simultaneously track changes in many plant metabolites and have found a number of applications in both systems biology and biosafety. Together with multivariate statistical analyses, NMR spectroscopy has been successfully applied to the characterisation of various herbs and plant products for quality control, authentication, determining geographical origin and for detecting adulteration of products. Additionally, the metabolic consequences of plant extracts have been demonstrated in experimental animals and in man using NMR-based metabonomics approaches to characterise the response. Here the application of NMR spectroscopy and chemometric tools for analysing plant-based products and their metabolic consequences are considered with particular emphasis on deconvolving biological complexity and minimising confounding biological variability with analytical`noise'.

Analytical Aspects of Plant Metabolite Profiling Platforms: Current Standings and Future Aims

“…We have been recently able to show in a preliminary case study performed on extracts of seven H. perforatum crude drug lots provided by commercial suppliers that HPLC−DAD and 1 H NMR fingerprinting had similar discriminating power in the PCA. Grouping within and separation between the lots were comparable; the most influential discriminators were found to be the phloroglucinol-type secondary metabolites such as hyperforin, adhyperforin, and flavonoids. , Hence, NMR-based metabolic profiling and fingerprinting can be predicted to show a discriminatory power similar to routinely used HPLC−DAD assays. Similar results obtained for chamomile 183 and tomato , do support our findings.…”

“…Grouping within and separation between the lots were comparable; the most influential discriminators were found to be the phloroglucinol-type secondary metabolites such as hyperforin, adhyperforin, and flavonoids. 64,190 Hence, NMRbased metabolic profiling and fingerprinting can be predicted to show a discriminatory power similar to routinely used HPLC-DAD assays. Similar results obtained for chamomile 183 and tomato 191,192 do support our findings.…”

Analytical Aspects of Plant Metabolite Profiling Platforms: Current Standings and Future Aims

“…We have been recently able to show in a preliminary case study performed on extracts of seven H. perforatum crude drug lots provided by commercial suppliers that HPLC−DAD and 1 H NMR fingerprinting had similar discriminating power in the PCA. Grouping within and separation between the lots were comparable; the most influential discriminators were found to be the phloroglucinol-type secondary metabolites such as hyperforin, adhyperforin, and flavonoids. , Hence, NMR-based metabolic profiling and fingerprinting can be predicted to show a discriminatory power similar to routinely used HPLC−DAD assays. Similar results obtained for chamomile 183 and tomato , do support our findings.…”

“…Grouping within and separation between the lots were comparable; the most influential discriminators were found to be the phloroglucinol-type secondary metabolites such as hyperforin, adhyperforin, and flavonoids. 64,190 Hence, NMRbased metabolic profiling and fingerprinting can be predicted to show a discriminatory power similar to routinely used HPLC-DAD assays. Similar results obtained for chamomile 183 and tomato 191,192 do support our findings.…”

NMR-Based Metabolomic Study on Isatis tinctoria: Comparison of Different Accessions, Harvesting Dates, and the Effect of Repeated Harvesting

“…Metabolomics is a very robust approach, in the sense that it offers a holistic view of the plant metabolome. Several groups have shown that the metabolome, as depicted by NMR spectroscopy, can be utilized for the classification of accessions and cultivars of medicinal plants and for the identification of pharmacologically active compounds in extracts. − More importantly, a multivariate metabolomics approach offers significant potential and distinct advantages in quality control of botanicals and herbal medicinal products when compared to the current approach of a quantitative determination of single compounds by means of chromatographic methods. , Our data demonstrate that within the same species it is possible to distinguish between accessions, dates of harvest, and even harvesting regime. NMR-based analysis can satisfy validation requirements, and NMR spectroscopy has been successfully used for official food control purposes .…”

“…20−24 More importantly, a multivariate metabolomics approach offers significant potential and distinct advantages in quality control of botanicals and herbal medicinal products when compared to the current approach of a quantitative determination of single compounds by means of chromatographic methods. 38,39 Our data demonstrate that within the same species it is possible to distinguish between accessions, dates of harvest, and even harvesting regime. NMRbased analysis can satisfy validation requirements, and NMR spectroscopy has been successfully used for official food control purposes.…”

Is Low-field NMR a Complementary Tool to GC-MS in Quality Control of Essential Oils? A Case Study: Patchouli Essential Oil

“…Measurement of the 17 deliberately adulterated PEOs allowed facile detection of 14 adulterations due to the presence of extra peaks. Adulteration with Clearwood did not change the fingerprint apart from a small additional peak of patchoulol ethyl ether (7). If one knows where to look for, Clearwood adulteration is thus detectable at 20 %.…”

Analytical Aspects of Plant Metabolite Profiling Platforms: Current Standings and Future Aims

“…We have been recently able to show in a preliminary case study performed on extracts of seven H. perforatum crude drug lots provided by commercial suppliers that HPLC−DAD and 1 H NMR fingerprinting had similar discriminating power in the PCA. Grouping within and separation between the lots were comparable; the most influential discriminators were found to be the phloroglucinol-type secondary metabolites such as hyperforin, adhyperforin, and flavonoids. , Hence, NMR-based metabolic profiling and fingerprinting can be predicted to show a discriminatory power similar to routinely used HPLC−DAD assays. Similar results obtained for chamomile 183 and tomato , do support our findings.…”

“…Grouping within and separation between the lots were comparable; the most influential discriminators were found to be the phloroglucinol-type secondary metabolites such as hyperforin, adhyperforin, and flavonoids. 64,190 Hence, NMRbased metabolic profiling and fingerprinting can be predicted to show a discriminatory power similar to routinely used HPLC-DAD assays. Similar results obtained for chamomile 183 and tomato 191,192 do support our findings.…”

NMR-Based Metabolomic Study on Isatis tinctoria: Comparison of Different Accessions, Harvesting Dates, and the Effect of Repeated Harvesting

“…Metabolomics is a very robust approach, in the sense that it offers a holistic view of the plant metabolome. Several groups have shown that the metabolome, as depicted by NMR spectroscopy, can be utilized for the classification of accessions and cultivars of medicinal plants and for the identification of pharmacologically active compounds in extracts. − More importantly, a multivariate metabolomics approach offers significant potential and distinct advantages in quality control of botanicals and herbal medicinal products when compared to the current approach of a quantitative determination of single compounds by means of chromatographic methods. , Our data demonstrate that within the same species it is possible to distinguish between accessions, dates of harvest, and even harvesting regime. NMR-based analysis can satisfy validation requirements, and NMR spectroscopy has been successfully used for official food control purposes .…”

“…20−24 More importantly, a multivariate metabolomics approach offers significant potential and distinct advantages in quality control of botanicals and herbal medicinal products when compared to the current approach of a quantitative determination of single compounds by means of chromatographic methods. 38,39 Our data demonstrate that within the same species it is possible to distinguish between accessions, dates of harvest, and even harvesting regime. NMRbased analysis can satisfy validation requirements, and NMR spectroscopy has been successfully used for official food control purposes.…”

Is Low-field NMR a Complementary Tool to GC-MS in Quality Control of Essential Oils? A Case Study: Patchouli Essential Oil

“…Measurement of the 17 deliberately adulterated PEOs allowed facile detection of 14 adulterations due to the presence of extra peaks. Adulteration with Clearwood did not change the fingerprint apart from a small additional peak of patchoulol ethyl ether (7). If one knows where to look for, Clearwood adulteration is thus detectable at 20 %.…”

Analytical Aspects of Plant Metabolite Profiling Platforms: Current Standings and Future Aims

“…We have been recently able to show in a preliminary case study performed on extracts of seven H. perforatum crude drug lots provided by commercial suppliers that HPLC−DAD and 1 H NMR fingerprinting had similar discriminating power in the PCA. Grouping within and separation between the lots were comparable; the most influential discriminators were found to be the phloroglucinol-type secondary metabolites such as hyperforin, adhyperforin, and flavonoids. , Hence, NMR-based metabolic profiling and fingerprinting can be predicted to show a discriminatory power similar to routinely used HPLC−DAD assays. Similar results obtained for chamomile 183 and tomato , do support our findings.…”

“…Grouping within and separation between the lots were comparable; the most influential discriminators were found to be the phloroglucinol-type secondary metabolites such as hyperforin, adhyperforin, and flavonoids. 64,190 Hence, NMRbased metabolic profiling and fingerprinting can be predicted to show a discriminatory power similar to routinely used HPLC-DAD assays. Similar results obtained for chamomile 183 and tomato 191,192 do support our findings.…”

NMR-Based Metabolomic Study on Isatis tinctoria: Comparison of Different Accessions, Harvesting Dates, and the Effect of Repeated Harvesting

“…Metabolomics is a very robust approach, in the sense that it offers a holistic view of the plant metabolome. Several groups have shown that the metabolome, as depicted by NMR spectroscopy, can be utilized for the classification of accessions and cultivars of medicinal plants and for the identification of pharmacologically active compounds in extracts. − More importantly, a multivariate metabolomics approach offers significant potential and distinct advantages in quality control of botanicals and herbal medicinal products when compared to the current approach of a quantitative determination of single compounds by means of chromatographic methods. , Our data demonstrate that within the same species it is possible to distinguish between accessions, dates of harvest, and even harvesting regime. NMR-based analysis can satisfy validation requirements, and NMR spectroscopy has been successfully used for official food control purposes .…”

“…20−24 More importantly, a multivariate metabolomics approach offers significant potential and distinct advantages in quality control of botanicals and herbal medicinal products when compared to the current approach of a quantitative determination of single compounds by means of chromatographic methods. 38,39 Our data demonstrate that within the same species it is possible to distinguish between accessions, dates of harvest, and even harvesting regime. NMRbased analysis can satisfy validation requirements, and NMR spectroscopy has been successfully used for official food control purposes.…”

Is Low-field NMR a Complementary Tool to GC-MS in Quality Control of Essential Oils? A Case Study: Patchouli Essential Oil

“…Measurement of the 17 deliberately adulterated PEOs allowed facile detection of 14 adulterations due to the presence of extra peaks. Adulteration with Clearwood did not change the fingerprint apart from a small additional peak of patchoulol ethyl ether (7). If one knows where to look for, Clearwood adulteration is thus detectable at 20 %.…”