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Prakash I.,The Coca-Cola Company | Chaturvedula V.S.P.,The Coca-Cola Company | Chaturvedula V.S.P.,Natural Products Research Group
Molecules | Year: 2014

Four new minor diterpene glycosides with a rare α-glucosyl linkage were isolated from a cyclodextrin glycosyltransferase glucosylated stevia extract containing more than 98% steviol glycosides. The new compounds were identified as 13-[(2-O-β-D-glucopyranosyl-3-O-(4-O-α-D-glucopyranosyl)-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(4-O-α-D-glucopyranosyl-β-D-glucopyranosyl) ester] (1), 13-[(2-O-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(4-O-(4-O-(4-O-α-D-glucopyranosyl)-α-D-glucopyranosyl)-α-D-glucopyranosyl)-β-D-glucopyranosyl ester] (2), 13-[(2-O-β-D-glucopyranosyl-3-O-(4-O-(4-O-(4-O-α-D-glucopyranosyl)-α-D-glucopyranosyl)-α-D-glucopyranosyl)-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid β-D-glucopyranosyl ester (3), and 13-[(2-O-β-D-glucopyranosyl-3-O-(4-O-(4-O-(4-O-α-D-glucopyranosyl)-α-D-glucopyranosyl)-α-D-glucopyranosyl)-β-D-glucopyranosyl-β-D-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(4-O-α-D-glucopyranosyl-β-D-glucopyranosyl) ester] (4) on the basis of extensive NMR and mass spectral (MS) data as well as hydrolysis studies. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Chi X.,University of Kentucky | Baba S.,Daiichi Sankyo | Tibrewal N.,University of Kentucky | Funabashi M.,Natural Products Research Group | And 2 more authors.
MedChemComm | Year: 2013

Muraminomicin is a lipopeptidyl nucleoside antibiotic produced by Streptosporangium amethystogenes SANK 60709. Similar to several members of this antibiotic family such as A-90289 and muraymycin, the structure of muraminomicin consists of a disaccharide comprised of two modified ribofuranose units linked by an O-β(1 → 5) glycosidic bond; however, muraminomicin holds the distinction in that both ribose units are 2-deoxy sugars. The biosynthetic gene cluster of muraminomicin has been identified, cloned and sequenced, and bioinformatic analysis revealed a minimum of 24 open reading frames putatively involved in the biosynthesis, resistance, and regulation of muraminomicin. Fives enzymes are likely involved in the assembly and attachment of the 2,5-dideoxy-5-aminoribose saccharide unit, and two are now functionally assigned and characterized: Mra20, a 5′-amino-2′,5′-dideoxyuridine phosphorylase and Mra23, a UTP:5-amino-2,5-dideoxy-α-d-ribose-1-phosphate uridylyltransferase. The cumulative results are consistent with the incorporation of the ribosyl appendage of muraminomicin via the archetypical sugar biosynthetic pathway that parallels A-90289 biosynthesis, and the specificity for this appendage is dictated primarily by the two characterized enzymes. © The Royal Society of Chemistry 2013.

Chaturvedula V.S.P.,Natural Products Research Group | Zamora J.,Natural Products Research Group
Natural Product Communications | Year: 2014

From the commercial extract of the leaves of the sweet plant Stevia rebaudiana Bertoni obtained from Sinochem Qingdao Co. Ltd., a new diterpene glycoside having three β-D-glucopyranosyl units of which two of them were connected in a relatively rare linkage of 3-β-D-glucobiosyl substitution at C-19 position of the aglycone steviol. The structure of the new compound has been characterized as 13-β-D-glucopyranosyloxy ent-kaur-16-en-19-oic acid-[(3-O-β-Dglucopyranosyl- β-D-glucopyranosyl) ester (1) on the basis of extensive 1D (1H and 13C) and 2D NMR (TOCSY, HMQC, and HMBC), and High Resolution mass spectroscopic data as well as hydrolysis studies. Copyright © 2014 Natural Product Communciations Inc.

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