Articolul precedent |
Articolul urmator |
798 13 |
Ultima descărcare din IBN: 2023-07-10 18:33 |
Căutarea după subiecte similare conform CZU |
547.59:543.429.23 (1) |
Chimie organică (475) |
Metode de analiză spectrală. Metode de analiză optică (65) |
SM ISO690:2012 GRINCO, Marina, BARBA, Alic, DUKA, Gh., UNGUR, Nikon, KULCIŢKI, Veaceslav. The use of qNMR spectroscopy for analytical evaluation of natural extracts. The case of apple pomace. In: New frontiers in natural product chemistry.: A destiny on the altar of research. Dedicated to academician Pavel Vlad, Ed. 6, 21 mai 2021, Chișinău. Chișinău, Republica Moldova: Tipografia "Artpoligraf", 2021, Ediția 6, p. 29. ISBN 978-9975-3336-7-2. DOI: https://doi.org/10.19261/nfnpc.2021.ab22 |
EXPORT metadate: Google Scholar Crossref CERIF DataCite Dublin Core |
New frontiers in natural product chemistry. Ediția 6, 2021 |
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Conferința " New frontiers in natural product chemistry." 6, Chișinău, Moldova, 21 mai 2021 | |||||||
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DOI: https://doi.org/10.19261/nfnpc.2021.ab22 | |||||||
CZU: 547.59:543.429.23 | |||||||
Pag. 29-29 | |||||||
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NMR spectroscopy is a convenient method for structural identification of both individual compounds and complex natural products mixtures. The main advantages of this powerful analytical tool are, among others, high resolution power, as well as simultaneous qualitative and quantitative evaluation of the investigated sample [1]. The current work presents the determination of ursolic 1 and oleanolic 2 acids content in apple pomace extracts basing on fast and reliable 2D NMR correlations [2]. Both triterpenic acids are present in the apple skins [3] and their biological activity spectrum is well known. Due to very similar chemical structure, simultaneous determination of acids 1 and 2 by routine techniques poses significant challenges which requires additional efforts and complex solutions. Ursolic acid (1) HO COOH Oleanolic acid (2) HO COOH The crude apple pomace was air dried in shade, grinded into a fine powder and extracted with EtOAc on combining cyclic passive macerations with ultrasonic irradiations on heating. Total extraction time did not exceed 3 hours. An aliquot of the crude extract was submitted to preparative chromatography on silica gel in order to isolate a pure mixture of 1 and 2 (cca. 30 % of total extract). The content of individual acids 1 and 2 was determined basing on the 2D NMR (1Н-13С HSQC) quantitative experiment on integration of 2D-plots of diagnostic signals corresponding to individual acids. Methyl paranitrobenzoate was used as internal standard and the calibration plots have been drawn separately for each acid. Basing on these data, determination of 1 and 2 was performed in both purified fractions and crude EtOAc-extracts from apple pomace. Obtained results showed identical data with parallel GC-MS experiments. |
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