- Phenolic glycosides from the twigs of Salix glandulosa
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As a part of an ongoing search for bioactive constituents from Korean medicinal plants, the phytochemical investigations of the twigs of Salix glandulosa afforded 12 new phenolic glycosides (1-12) and a known analogue (13). The structures of 1-13 were characterized by a combination of NMR methods (1H and 13C NMR, 1H-1H COSY, HMQC, and HMBC), chemical hydrolysis, and GC/MS. The absolute configuration of 13 [(1R,2S)-2-hydroxycyclohexyl-2′-O-trans-p-coumaroyl-β-d- glucopyranoside] was determined for the first time. Compounds 1-3, 6, and 7 exhibited inhibitory effects on nitric oxide production in lipopolysaccharide- activated murine microglial cells (IC50 values in the range 6.6-20.5 μM).
- Kim, Chung Sub,Kwon, Oh Wook,Kim, Sun Yeou,Choi, Sang Un,Kim, Jae Yoon,Han, Ji Young,Choi, Soo Im,Choi, Jong Gil,Kim, Ki Hyun,Lee, Kang Ro
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p. 1955 - 1961
(2014/10/16)
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- Enantioselective glucosylation of (±)-secondary alcohols with plant glucosyltransferases
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Two glucosyltransferases were isolated from plant cell cultures of Catharanthus roseus and Nicotiana tabacum. The enzyme from C. roseus enantioselectively glucosylated (±)-secondary alcohols to give the glucosides of (R)-alcohols, while the glucosylation with that from N. tabacum gave preferentially the glucosides of (S)-alcohols.
- Shimoda, Kei,Kubota, Naoji,Hamada, Hiroki
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p. 2319 - 2321
(2007/10/03)
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- Stereochemical Studies of Enzymatic Transglycosylation using Sulfolobus solfataricus
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Stereochemistry of β-glycosyl transfer from phenyl β-D-galactoside, lactose, and phenyl β-D-glucoside to various 1,2-, 1,3-, and 1,4-diols, a secondary-tertiary diol, a cyclic diol, and a racemic alkohol has been studied using β-glycosidase activity in a crude preparation from the thermophilic archaebacterium Sulfolobus solfataricus.Good enantioselection for the galactosyl transfer to the secondary hydroxy group of different 1,2-diols has been observed.Good yields in comparison with enzymes from other sources, and results concerning the reaction's regioselectivity, have also been reported.
- Trincone, Antonio,Nicolaus, Barbara,Lama, Licia,Gambacorta, Agata
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p. 2841 - 2844
(2007/10/02)
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- DIASTEREOSELECTIVE D-GALACTOPYRANOSYL TRANSFER TO MESO DIOLS CATALYZED BY β-GALACTOSIDASES
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Described is the D-galactopyranosyl transfer from 2 and β-D-lactose, respectively, to the meso diols 1a-e catalyzed by E. coli β-galactosidase and Asp. oryzae β-galactosidase yielding the mono-β-D-galactosides 3a-e with de-values up to 96percent.
- Gais, Hans-Joachim,Zeissler, Axel,Maidonis, Peter
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p. 5743 - 5744
(2007/10/02)
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- STEREOSPECIFIC PREPARATION OF MONOGLUCOSIDES OF OPTICALY ACTIVE trans-1,2-CYCLOHEXANEDIOLS BY ENZYMIC TRANS-D-GLUCOSYLATION, AND (13)C-N.M.R. SPECTROSCOPY OF THE RESULTING MONO-D-GLUCOPYRANOSIDES
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Anomeric mono-D-glucosides of optically active trans-1,2-cyclohexanediols were stereoselectively prepared from the racemic mixture by means of enzymic trans-D-glucosylation using crude enzyme preparations that are commercially available or are utilized for food manufacturing.The (13)C-n.m.r. spectra of these D-glucosides were characterized, and the stereochemical influence, on the glycosylation shifts of cyclohexanol, of the vicinal hydroxyl substitution was discussed in comparison with that of vicinal alkyl substitution reported previously.
- Itano, Kayoko,Yamasaki, Kazuo,Kihara, Chikako,Tanaka, Osamu
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