From Targeted Quantification to Untargeted Metabolomics

Abstract

Metabolomics is an emerging and rapidly evolving technology tool, which involves quantitative and qualitative metabolite assessments science. It offers tremendous promise for different applications in various fields such as medical, environmental, nutrition, and agricultural sciences. Metabolomic approach is based on global identification of a high number of metabolites present in a biological fluid. This allows to characterize the metabolic profile of a given condition and to identify which metabolites or metabolite patterns may be useful in the discrimination between different groups. The use of one mass spectrometry (MS) platform from targeted quantification to untargeted metabolomics will make more efficient workflows in many fields and should allow projects to be more easily undertaken and realized. Metabolomics can be divided into non-targeted and targeted. The first one can analyze metabolites derived from the organisms comprehensively and systematically, so it is an unbiased metabolomics analysis that can discover new biomarkers. Targeted metabolomics, on the other hand, is the study and analysis of specific metabolites. Both have their own advantages and disadvantages, and are often used in combination for discovery and accurate weight determination of differential metabolites, and allow in-depth research and analysis of subsequent metabolic molecular markers. Targeted and non-targeted metabolomics are involved in food identification, disease research, animal model verification, biomarker discovery, disease diagnosis, drug development, drug screening, drug evaluation, clinical plant metabolism and microbial metabolism research. The aim of this chapter is to highlight the versatility of metabolomic analysis due to both the enormous variety of samples and the no strict barriers between quantitative and qualitative analysis. For this purpose, two examples from our group will be considered. Using non-targeted metabolomics in opposite Antarctic cryptoendolytic communities exposed to the sun, we revealed specific adaptations. Instead, through the targeted metabolomics applied to the urine during childbirth, we identified a different distribution of specific metabolites and the metabolic differences allowed us to discriminate between the two phases of labor, highlighting the metabolites most involved in the discrimination. The choice of these two approaches is to highlight that metabolomic analysis can be applied to any sample, even physiologically and metabolomically very distant, as can be microorganisms living on Antarctic rocks and biological fluids such as urine.

Integrated transcriptome and metabolome profiling of Camellia reticulata reveal mechanisms of flower color differentiation

“…We further performed targeted metabolome profiling with the petals of three contrasting genotypes of C. reticulata with the aim of identifying specific flavonoid/anthocyanin compound(s) that may account for white coloration observed in XJ and TZM genotypes relative to HHYC genotype. Targeted metabolome profiling offers absolute quantification, higher accuracy, and greater selectivity ( Beckles and Roessner, 2012 ; Cao et al, 2020 ; Lelli et al, 2021 ). From this, 310 metabolites comprising 282 and 28 flavonoid/anthocyanin and tannin compounds, were detected, respectively ( Supplementary Table S4 ).…”

Evaluation of Sustainable Recycled Products to Increase the Production of Nutraceutical and Antibacterial Molecules in Basil Plants by a Combined Metabolomic Approach

“…Targeted metabolomics identifies a predefined group of metabolites for which standards are available to provide a sensitive and accurate detection for metabolite quantification [ 32 , 33 ]. On the other hand, untargeted metabolomics focuses on the simultaneous measurement of as many unknown metabolites as possible in a biological system, enabling a more exhaustive picture on the changes of the complete metabolic profile based on the identification of compounds affected by an external treatment [ 34 , 35 ].…”

Defining Blood Plasma and Serum Metabolome by GC-MS

“…Target metabolomics allows to qualitatively and quantitatively characterize a specific, often relatively narrow, group of metabolites [76]. In this case, at the extraction stage, it is required to reduce interference from off-target compounds and increase the completeness of extraction of target groups of metabolites.…”

“…Panoramic metabolomics is aimed at the broadest possible coverage of a wide variety of chemically diverse metabolites [76]. For such global tasks, an unselective extractant is selected that will effectively extract substances belonging to different chemical classes to ensure adequate depth of metabolite coverage and represent the actual composition of the sample under study.…”