title: Enzymatic synthesis of the glycosides of calystegines B1 and B2 and their glycosidase inhibitory activities.
abstract: Several glycosides of calystegines B1 and B2 were synthesized by use of rice alpha-glucosidase and the whole cells of Rhodotorula lactosa, and their glycosidase inhibitory activities were investigated. Incubation of mixture of calystegine B1 and maltose with rice alpha-glucosidase gave 3-O-alpha-D-glucopyranosylcalystegine B1 (2, 11.3%). An enzymatic beta-transglucosylation reaction of calystegines B1 or B2 with cellobiose using the whole cells of R. lactosa gave 3-O-beta-D-glucopyranosylcalystegine B1 (1) (0.9%) or 4-O-beta-D-glucopyranosylcalystegine B2 (3, 11.2%), respectively, while similar beta-transgalactosylation of calystegine B2 from lactose gave 4-O-beta-D-galactopyranosylcalystegine B2 (4, 10.1%). The glycosylation of calystegines B1 and B2 markedly decreased or abolished their inhibition against beta-glucosidase, alpha- or beta-galactosidase. Compound 4 however retained more or less the potency of calystegine B2 against trehalase. Interestingly, compound 1 was a noncompetitive inhibitor of rice alpha-glucosidase, with a Ki value of 0.9 +/- 0.1 microM.
authors.affiliation: Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Asano
authors.forename: A
authors.initials: A
authors.lastname: Kato
authors.forename: H
authors.initials: H
authors.lastname: Kizu
authors.forename: K
authors.initials: K
authors.lastname: Matsui
authors.forename: R C
authors.initials: RC
authors.lastname: Griffiths
authors.forename: M G
authors.initials: MG
authors.lastname: Jones
authors.forename: A A
authors.initials: AA
authors.lastname: Watson
authors.forename: R J
authors.initials: RJ
authors.lastname: Nash
mesh_terms: D000818:Animals; D002417:Cattle; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000494:pharmacology; D005656:Fungal Proteins / Q000037:antagonists & inhibitors; D005959:Glucosidases / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors*; D006027:Glycosides / Q000096:biosynthesis*; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy; D009662:Nortropanes / Q000378:metabolism*; D012275:Oryza / Q000201:enzymology; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D012248:Rhodotorula / Q000378:metabolism; D012991:Solanaceous Alkaloids; D013552:Swine
chemical_list: D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D006027:Glycosides; D009662:Nortropanes; D010940:Plant Proteins; D012991:Solanaceous Alkaloids; C095613:calystegine B(2); C110567:calystegine B1; D005959:Glucosidases; D006026:Glycoside Hydrolases