Structural elucidation of a novel transglycosylated compound α-glucosyl rhoifolin and of α-glucosyl rutin by NMR spectroscopy.
We report the full assignment of1H and13C NMR signals belonging to α-glucosyl rhoifolin (Rhf-G), a novel transglycosylated compound synthesized from a flavone glycoside, rhoifolin, as well as its chemical structure. Furthermore, we report the complete NMR signal assignment for another transglycosylated compound, α-glucosyl rutin (Rutin-G), as the signals corresponding to its sugar moieties had not been identified. Electrospray ionization-mass spectrometry along with multiple NMR methods revealed that Rhf-G possesses three sugar moieties in its chemical structure. The additional glucose was bound directly via a transglycosylation to rhoifolin at position 3a of the sugar moiety. Interestingly, intramolecular hydrogen bonds in the basic Rhf-G and Rutin-G skeletons were confirmed by HMBC experiments. These findings will be helpful for comprehensive NMR studies on transglycosylated compounds in food, cosmetic, and pharmaceutical fields.
Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan.
Chisa
C
Aoki
Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan.
Yoshihiro
Y
Takeuchi
Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan. Electronic address: ken-h@faculty.chiba-u.jp.
Kenjirou
K
Higashi
Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan.
Yuta
Y
Okamoto
Toyo Sugar Refining Co., Ltd., 18-20 Koami-Cho, Nihonbashi, Chuo-ku, Tokyo 103-0016, Japan.
Akihito
A
Nakanishi
Toyo Sugar Refining Co., Ltd., 18-20 Koami-Cho, Nihonbashi, Chuo-ku, Tokyo 103-0016, Japan.
Mahamadou
M
Tandia
RIKEN-Max Planck Joint Research Center for Systems Chemical Biology, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Jun
J
Uzawa
Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan.
Keisuke
K
Ueda
Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8675, Japan.
Kunikazu
K
Moribe
D004187:Disaccharides / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry*; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy; D012431:Rutin / Q000737:chemistry*; D005947:Glucose / Q000031:analogs & derivatives; D008358:Mannose / Q000031:analogs & derivatives; D047310:Apigenin
D004187:Disaccharides; D005419:Flavonoids; D006027:Glycosides; D012431:Rutin; C089378:rhoifolin; D005947:Glucose; D008358:Mannose; D047310:Apigenin
Intramolecular interaction; NMR; Rhoifolin; Rutin; Signal assignment; Transglycosylated compound