China
Africa
Explore chapters and articles related to this topic
Biochemical Markers in Ophthalmology
Published in Ching-Yu Cheng, Tien Yin Wong, Ophthalmic Epidemiology, 2022
Abdus Samad Ansari, Pirro G. Hysi
Metabolites are small molecules or compounds that are either the end or by-product of biochemical reactions in the living cell. Metabolomics is a newly emerging field that extensively analyzes the presence of metabolites in a biological specimen. Although originally metabolites were used to diagnose complex metabolic disease and monogenic disorders such as inborn errors of metabolism [114], it has evolved well beyond the scope of basic clinical chemistry techniques, to include the parallel “quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modifications” [115]. Metabolomics allows for the accurate analysis of hundreds of metabolites, permitting the characterization of metabolic phenotypes, metabolic derangements that inspire disease, the identification of innovative therapeutic targets, and the detection of biomarkers that may guide treatment and monitor disease progression [116].
Role of Metabolism in Chemically Induced Nephrotoxicity
Published in Robin S. Goldstein, Mechanisms of Injury in Renal Disease and Toxicity, 2020
The strategy that has been employed to demonstrate the requirement of β-lyase-dependent bioactivation in the nephrotoxicity of cysteine S-conjugates involves the use of specific enzyme inhibitors, cosubstrates, and nonmetabolizable analog (Figure 12). By dissecting the pathway and examining each step, the bioactivation mechanism can be validated. The metabolic pathway essentially involves transport of any one of three species into the cell, two hydrolytic reactions to produce the penultimate metabolite (i.e., the cysteine S-conjugate), and the β-lyase reaction to generate the reactive species.
Nanoparticle-Based Delivery of Plant Metabolites
Published in Megh R. Goyal, Hafiz Ansar Rasul Suleria, Ademola Olabode Ayeleso, T. Jesse Joel, Sujogya Kumar Panda, The Therapeutic Properties of Medicinal Plants, 2019
Shesan John Owonubi, Emmanuel Mukwevho, Neerish Revaprasadu
Plants are known to produce compounds (such as alcohols, amino acids, carbohydrates, nucleotides, phytosterols, and some organic acids), which are typically key to the maintenance of normal physiology processes and are important in growth, development, and reproduction. These compounds are called primary metabolites. In contrast, plants also produce secondary metabolites (such as: sterols, terpenes, alkaloids, phenols, tannins, carotenoids, flavonoids, waxes, gums), which are not directly linked to actions that effect the growth, reproduction, and development of the living plant, but seem to have some effect on the function of ecology and the mechanism of defense by production of pigments in some cases [24]. These secondary metabolites are known to be produced from the modification of primary metabolite by enzymatic means. Figure 15.4 shows the pathways to produce some secondary metabolites.
In vitro hepatic metabolism of the natural product quebecol
Published in Xenobiotica, 2023
The identification of the metabolites and the elucidation of the disposition pathways provide an understanding into the extent of metabolism. Another important concept for drug metabolism consists of the rate of metabolism which can be measured by the kinetics of depletion of substrates and/or formation of metabolites (Nagar et al. 2014). Monitoring kinetics by metabolite formation requires authentic metabolite standards to prepare calibration curves in the analytical method, and in our case requires monitoring formation of multiple products. In contrast, the substrate depletion approach is a reliable alternative to calculate the kinetic parameters by monitoring the depletion of the substrate as a function of time (Obach and Reed-Hagen 2002; Youdim and Dodia 2010; Schwaninger et al. 2011; Caspar et al. 2018). We have previously used the substrate depletion approach to follow UGT metabolism of enterolactone (Lin et al. 2013) and for this study, we have validated an HPLC-UV method to measure the Phase 2 glucuronidation using the substrate depletion approach.
Not just a gut feeling: a deep exploration of functional bacterial metabolites that can modulate host health
Published in Gut Microbes, 2022
The primary method of metabolite identification across the analyzed studies is to place emphasis on a particular disease state known to be modulated by microbes or associated with a specific microbial metabolite. Selection of a focal metabolic state allows for targeted stratification of dysregulation and comparison between healthy controls in the second major stage of metabolite identification. Then, high throughput (omics) analyses were conducted to discriminate dysregulated metabolites or bacterial species. For example, untargeted metabolomics analyses were conducted to some degree, either by the authors or extracted from previous analyses, in several reported studies (Table 1).14–20 Metabolomics, defined as “the comprehensive analysis of metabolites (small molecule intermediates or end products of metabolic processes) in a biological specimen”, is an emerging technique that allows for up to the minute phenotypic profiling of an organism’s metabolic state.21 Metabolomics can be a powerful tool for identification of metabolites or metabolic panels that can be used as biomarkers for various disease states, including cancers, neurodegenerative diseases, and metabolic abnormalities.22–24
Partial least squares regression with compositional response variables and covariates
Published in Journal of Applied Statistics, 2021
Jiajia Chen, Xiaoqin Zhang, Karel Hron
The PLS regression model discussed in the previous section is applied to a data set from metabolomics, where 16 Astragali Radix samples and 16 rats were collected, respectively [19]. This data set thus includes the chemical metabolites of Astragali Radix and the plasma metabolites of rat after giving Astragali Radix. The chemical metabolites consist of two compositional variables: primary metabolites 1. The plasma metabolites and chemical metabolites data sets are given in Appendix A.4.