title: Instant coffee extract with high chlorogenic acids content inhibits hepatic G-6-Pase in vitro, but does not reduce the glycaemia.
abstract: Coffee is the main source of chlorogenic acid in the human diet, and it contains several chlorogenic acid isomers, of which the 5-caffeoylquinic acid (5-CQA) is the predominant isomer. Because there are no available data about the action of chlorogenic acids from instant coffee on hepatic glucose-6-phosphatase (G-6-Pase) activity and blood glucose levels, these effects were investigated in rats. The changes on G-6-Pase activity and liver glucose output induced by 5-CQA were also investigated. Instant coffee extract with high chlorogenic acids content (37.8%) inhibited (p < 0.05) the G-6-Pase activity of the hepatocyte microsomal fraction in a dose-dependent way (up to 53), but IV administration of this extract did not change the glycaemia (p > 0.05). Similarly, 5-CQA (1 mM) reduced (p < 0.05) the activity of microsomal G-6-Pase by about 40%, but had no effect (p > 0.05) on glucose output arising from glycogenolysis in liver perfusion. It was concluded that instant coffee extract with high content of chlorogenic acids inhibited hepatic G-6-Pase in vitro, but failed to reduce the glycaemia probably because the coffee chlorogenic acids did not reach enough levels within the hepatocytes to inhibit the G-6-Pase and reduce the liver glucose output.
authors.affiliation: Department of Physiological Sciences, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Bruna Kempfer
authors.initials: BK
authors.lastname: Bassoli
authors.affiliation: Department of Physiological Sciences, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Priscila
authors.initials: P
authors.lastname: Cassolla
authors.affiliation: Department of Physiological Sciences, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Glaucia Regina
authors.initials: GR
authors.lastname: Borba-Murad
authors.affiliation: Department of Biochemistry, State University of Maringá, Maringá, PR, Brazil.
authors.forename: Jorgete
authors.initials: J
authors.lastname: Constantin
authors.affiliation: Department of Biochemistry, State University of Maringá, Maringá, PR, Brazil.
authors.forename: Clairce Luzia
authors.initials: CL
authors.lastname: Salgueiro-Pagadigorria
authors.affiliation: Department of Pharmacy and Pharmacology, State University of Maringá, Maringá, PR, Brazil.
authors.forename: Roberto Barbosa
authors.initials: RB
authors.lastname: Bazotte
authors.affiliation: Department of Physiological Sciences, State University of Londrina, Londrina, PR, Brazil.
authors.forename: Helenir Medri
authors.initials: HM
authors.lastname: de Souza
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002726:Chlorogenic Acid / Q000737:chemistry / Q000494:pharmacology*; D003069:Coffee / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D005952:Glucose-6-Phosphatase / Q000037:antagonists & inhibitors*; D038321:Glycemic Index / Q000187:drug effects; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D010936:Plant Extracts / Q000737:chemistry*; D011801:Quinic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D001786:Blood Glucose; D003069:Coffee; D004791:Enzyme Inhibitors; D010936:Plant Extracts; C472707:caffeoylquinic acid; D011801:Quinic Acid; D002726:Chlorogenic Acid; D005952:Glucose-6-Phosphatase
keywords: chlorogenic acid; glucose-6-phosphatase; glycaemia; instant coffee extract; liver glucose output; liver perfusion