Identification, natural products

Drug discovery Lead candidate Screening Protein identification natural products identification metabolic stability profiles molecular weight determination for combinatorial/ medicinal chemistry support. 

Lead identification Natural products identification Natural products dereplication Ackerman et al., 1996a... 

Applications. The most ubiquitous use of infrared spectrometry is chemical identification. It has long been an important tool for studying newly synthesi2ed compounds in the research lab, but industrial identification uses cover an even wider range. In many industries ir spectrometry is used to assay feedstocks (qv). In the flavors (see Flavors and spices), fragrances (see Perfumes), and cosmetics (qv) industries, it can be used not only for gross identification of feedstocks, but for determining specific sources. The spectra of essential oils (see Oils, essential), essences, and other natural products vary with the season and source. Adulteration and dilution can also be identified. 

Isolation and identification of substances (natural products from nature, protein purification and characterisation, etc). 

Until the second half of the twentieth century, the structure of a substance—a newly discovered natural product, for example—was determined using information obtained from chemical reactions. This information included the identification of functional groups by chemical tests, along with the results of experiments in which the substance was broken down into smaller, more readily identifiable fragments. Typical of this approach is the demonstration of the presence of a double bond in an alkene by catalytic hydrogenation and subsequent determination of its location by ozonolysis. After-considering all the available chemical evidence, the chemist proposed a candidate structure (or structures) consistent with the observations. Proof of structure was provided either by converting the substance to some already known compound or by an independent synthesis. 

The identification of non-peptidic lead structures remains a challenge. Screening of natural product extracts led to the identification of two po-lyhydroxylated biphenyls ((10a) and (10b), Figure 2.13) that show submicromolar inhibition of the viral protease [156]. A recent report discloses polyesters of glucose (11) and gallic acid (12) as micromolar inhibitors of the NS3 protease [157]. 

Sche, P. P., McKenzie, K. M., White, J. D., and Austin, D. J. (1999). Display cloning functional identification of natural product receptors using cDNA-phage display. Chem. Biol. 6, 707-716. 

Isolation and Identification of Eukaryotic Initiation Factor 4A as a Molecular Target for the Marine Natural Product Pateamine A 303... 

J. Connan, A. Nissenbaum, Conifer tar on the keel and hull planking of the Ma agan Mikhael ship (Israel, 5th century BC) identification and comparison with natural products and artefacts employed in boat construction, Journal of Archaeological Science, 30, 709 719 (2003). 

Although the mass spectra of aged diterpenoid resins are generally not characteristic enough for a clear identification, some natural products show characteristic peaks above m/z 325. These signals can be explained by particular constituents of the respective resins, so-called biomarkers. For example, copaiba balsam shows an intense peak at m/z 385, which can be attributed to 3-acetoxy-copaiferic acid [51] (see Figure 5.11). Another... 

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