title: Evaluation of ascorbic acid 2-O-alpha-glucoside as vitamin C source: mode of intestinal hydrolysis and absorption following oral administration.
abstract: Ascorbic acid 2-O-alpha-glucoside (AA-2G) has been reported to have antiscorbutic activity in guinea pigs. The present experiments examined the metabolic fate of AA-2G following ingestion. Oral administration of AA-2G (96 mg) to guinea pigs resulted in a remarkable increase of ascorbic acid in various tissues as well as plasma, but intact AA-2G was detected only in plasma, but intact AA-2G was detected only in plasma and urine in small amounts. The absorption efficiency of AA-2G and ascorbic acid was further determined by using everted gut sacs of rats. Ascorbic acid released from AA-2G on the mucosal side was effectively taken up across intestinal membranes into the serosal side, whereas AA-2G poorly permeated via a passive transport system. The hydrolysis of AA-2G on the mucosal surface of everted gut was completely inhibited by an alpha-glucosidase inhibitor and the hydrolytic activity of a crude membrane extract diminished to one-forth after immunoprecipitation with the antibody specific to maltase. From these results, it is concluded that ingested AA-2G serves as a vitamin C source through the hydrolysis by intestinal membrane-bound alpha-glucosidase, mainly maltase, and the subsequent absorption of released ascorbic acid.
authors.affiliation: Department of Immunochemistry, Faculty of Pharmaceutical Sciences, Okayama University, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Muto
authors.forename: K
authors.initials: K
authors.lastname: Terasawa
authors.forename: I
authors.initials: I
authors.lastname: Yamamoto
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000493:pharmacokinetics; D006168:Guinea Pigs; D006868:Hydrolysis; D007408:Intestinal Absorption / Q000502:physiology*; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014018:Tissue Distribution / Q000187:drug effects; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: C065378:ascorbic acid 2-O-glucoside; D000520:alpha-Glucosidases; D001205:Ascorbic Acid