L-Ascorbic acid α-glucoside formed by regioselective transglucosylation with rat intestinal and rice seed α-glucosidases : Its improved stability and structure determination

• 山本 格

  Department of Immunochemistry, Faculty of Pharmaceutical Science, Okayama University

• 武藤 徳男

  Department of Immunochemistry, Faculty of Pharmaceutical Science, Okayama University

• 村上 公基

  Department of Immunochemistry, Faculty of Pharmaceutical Science, Okayama University

• 菅 貞治

  Department of Immunochemistry, Faculty of Pharmaceutical Science, Okayama University

• 山口 久夫

  Teijin Institute for Bio-Medical Research

抄録

The definite structure and chemical stability of a new glucoside of L-ascorbic acid (AA) which was enzymatically glucosylated with rat intestinal and rice seed α-glucosidases were reported. The stability of this AA derivative in water under aerobic conditions was proved by its remarkable resistance against enhanced oxidative degradation by heat, Cu^<2+> ion or ascorbate oxidase, and it was found to have no reducing activity toward radicals. These properties were obviously distinguishable from those of AA. This glucoside was effectively hydrolyzed by α-glucosidases which possessed the ability to synthesize itself, resulting in the liberation of AA activity. The conjugate was composed of equimoles of AA and glucose. Nuclear magnetic resonance spectra, mass spectra, pH profiles of ultraviolet spectra and pK_a value of 3.10 supported the coupling of α-glucose to the 2-position of AA.From these results, its structure was assigned 2-O-α-D-glucopyranosyl-L-ascorbic acid, being distinct from 6-O-α-D-glucopyranosyl-L-ascorbic acid formed with Aspergillus niger α-glucosidase. These findings indicate that the 2-O-glucoside formed by regioselective transglucosylation withstands oxidateive degradation even in aqueous solutions and it can be used as an available active AA source for multicomponent liquid products.

収録刊行物

• Chem Pharm Bull

  Chem Pharm Bull 38 3020-3023, 1990

  公益社団法人日本薬学会

キーワード

• L-ascorbic acid
• L-ascorbic acid 2-glucoside
• structural determination
• chemical stability
• regioselective transglucosylation
• enzymatic hydrolysis
• α-glucosidase

詳細情報

• CRID: 1572543027345341824
• NII論文ID: 110003628206
• NII書誌ID: AA00602100
• ISSN: 00092363
• 本文言語コード: en
• データソース種別:
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