Carbon-13 NMR spectroscopy of steroidal sapogenins and steroidal saponins

Agrawal, Pawan K.; Jain, D. C.; Gupta, Rajesh; Thakur, Raghunath S.

doi:10.1016/s0031-9422(00)80653-6

Cited by 573 publications

(380 citation statements)

References 69 publications

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“…The anomeric proton of the fucose was hidden by the HOD peak, but its coupling constant could be derived at 4.0 Hz from the coupling constants of H2, confirming an untouched a-configuration of the methyl a-L-fucoside. All 13 C chemical shifts were in acceptable accordance with the monomeric reference compounds methyl a-D-xyloside and methyl a-Lfucoside (Agrawal et al, 1985). The cross-peak at 5.09/63.4 in the HMBC spectrum corresponds to xylose(H1)-xylose(C5), proving that the xylose is in pyranose form, which also can be seen from the 13 C data, where the shifts are below 80 ppm (xylose in furanose form will have shifts above 80 ppm).…”

Section: Determination Of the Disaccharide Linkagesupporting

confidence: 56%

Arabidopsis thaliana RGXT1 and RGXT2 Encode Golgi-Localized (1,3)-α-d-Xylosyltransferases Involved in the Synthesis of Pectic Rhamnogalacturonan-II

Egelund¹,

Petersen²,

Motawia³

et al. 2006

The Plant Cell

126

144

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Two homologous plant-specific Arabidopsis thaliana genes, RGXT1 and RGXT2, belong to a new family of glycosyltransferases (CAZy GT-family-77) and encode cell wall (1,3)-a-D-xylosyltransferases. The deduced amino acid sequences contain single transmembrane domains near the N terminus, indicative of a type II membrane protein structure. Soluble secreted forms of the corresponding proteins expressed in insect cells showed xylosyltransferase activity, transferring D-xylose from UDPa-D-xylose to L-fucose. The disaccharide product was hydrolyzed by a-xylosidase, whereas no reaction was catalyzed by b-xylosidase. Furthermore, the regio-and stereochemistry of the methyl xylosyl-fucoside was determined by nuclear magnetic resonance to be an a-(1,3) linkage, demonstrating the isolated glycosyltransferases to be (1,3)-a-D-xylosyltransferases. This particular linkage is only known in rhamnogalacturonan-II, a complex polysaccharide essential to vascular plants, and is conserved across higher plant families. Rhamnogalacturonan-II isolated from both RGXT1 and RGXT2 T-DNA insertional mutants functioned as specific acceptor molecules in the xylosyltransferase assay. Expression of RGXT1-and RGXT2-enhanced green fluorescent protein constructs in Arabidopsis revealed that both fusion proteins were targeted to a Brefeldin A-sensitive compartment and also colocalized with the Golgi marker dye BODIPY TR ceramide, consistent with targeting to the Golgi apparatus. Taken together, these results suggest that RGXT1 and RGXT2 encode Golgi-localized (1,3)-a-D-xylosyltransferases involved in the biosynthesis of pectic rhamnogalacturonan-II.

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Section: Determination Of the Disaccharide Linkagesupporting

confidence: 56%

Arabidopsis thaliana RGXT1 and RGXT2 Encode Golgi-Localized (1,3)-α-d-Xylosyltransferases Involved in the Synthesis of Pectic Rhamnogalacturonan-II

Egelund¹,

Petersen²,

Motawia³

et al. 2006

The Plant Cell

126

144

View full text Add to dashboard Cite

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“…The anomeric configuration of the Glc moiety was ascertained to be from the relatively large J value of the anomeric proton (7.9 Hz), and those of the Rha and Rha 0 units to be on the basis of their 13 C-NMR shifts. 12) The confirmative evidence for the sugar sequences of 6 was obtained from the HMBC correlations between H-1 of Rha at 6.39 and C-2 of Glc at 77.7, H-1 of Rha 0 at 5.87 and C-4 of Glc at 78.4, and between H-1 of Glc at 4.96 and C-3 of the aglycone at 73.6. Accordingly, the structure of 6 was formulated as (…”

mentioning

confidence: 73%

“…were compared with those of (25R)-spirost-5-en-3-ol (diosgenin), 12) the signals assignable to the H 2 -12 and C-12 methylene protons and carbon were displaced by a hydroxylmethine proton at 4.01 (br s, W 1=2 ¼ 12:5 Hz, H-12) and carbon at 71.5 (C-12). Furthermore, an NOE correlation was observed between H-12 and Me-18 in the NOESY spectrum of 7a.…”

mentioning

confidence: 99%

New Steroidal Glycosides from Rhizomes ofClintonia udensis

Matsuo

Watanabe

Mimaki

2008

Bioscience, Biotechnology, and Biochemistry

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“…20,21 In the HMBC spectrum, a correlation peak between the signals at δ H 4.80 (H-1 of terminal glucosyl) and δ C 75.4 (C-26 of aglycon) implied that one glucose unit was attached at C-26 of the aglycon, which is a structural feature most frequently encountered in the plant furostanol saponins. 15 Consequently, a tetraglycoside was assumed to be located at C-3 of the aglycon. The sequence of the tetrasaccharide, which was the same as the known compounds …”

Section: Resultsmentioning

confidence: 99%

Steroidal and pregnane glycosides from Ypsilandra thibetica

Liu

Chen

Lü

et al. 2012

Nat. Prod. Bioprospect.

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Abstract:The whole plants of Ypsilandra thibetica have been analyzed as part of a systematic study on saponin constituents of medicinal plants. This has resulted in the isolation of two new bisdesmosidic furostanol saponins, named ypsilandroside P (1) and ypsilandroside Q (2), and one new pregnane glycoside, named ypsilandroside R (3), together with nine known steroidal glycosides. Their structures were elucidated on the basis of extensive spectroscopic analysis, including that of 2D NMR data, and the results of acidic hydrolysis. Ypsilandroside P (1) was cytotoxicity against two human tumor cell lines.

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Carbon-13 NMR spectroscopy of steroidal sapogenins and steroidal saponins

Cited by 573 publications

References 69 publications

Arabidopsis thaliana RGXT1 and RGXT2 Encode Golgi-Localized (1,3)-α-d-Xylosyltransferases Involved in the Synthesis of Pectic Rhamnogalacturonan-II

Arabidopsis thaliana RGXT1 and RGXT2 Encode Golgi-Localized (1,3)-α-d-Xylosyltransferases Involved in the Synthesis of Pectic Rhamnogalacturonan-II

New Steroidal Glycosides from Rhizomes ofClintonia udensis

Steroidal and pregnane glycosides from Ypsilandra thibetica

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