title: Potent α-glucosidase inhibitors isolated from Ginkgo biloba leaves.
abstract: In vitro α-glucosidase inhibitory activity of Ginkgo biloba leaves was investigated. The inhibitory activity of methanol extracts from yellow and green leaves was 13.8 and 40.1 μg mL(-1), respectively. Each methanol extract was separated into its respective fraction by solvent-solvent extraction with n-hexane, chloroform, ethyl acetate and n-butanol. The n-hexane fractions (in both methanol extracts from green and yellow leaves) exhibited high α-glucosidase inhibitory activity with IC50 values of 13.6 and 13.4 μg mL(-1), respectively. Further fractionation of the n-hexane fractions by silica gel column chromatography gave the most active fraction which was identified as ginkgolic acid (C13:0) and a mixture (C13:0, C15:0, C15: 1, C17:1 and C17:2). Ginkgolic acid (C13:0) exhibited the highest α-glucosidase inhibitory activity. This is the first study to successfully isolate ginkgolic acids as α-glucosidase inhibitors.
authors.forename: Agus
authors.initials: A
authors.lastname: Sukito
authors.forename: Sanro
authors.initials: S
authors.lastname: Tachibana
mesh_terms: D020001:1-Butanol / Q000737:chemistry; D000085:Acetates / Q000737:chemistry; D005591:Chemical Fractionation; D002725:Chloroform / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D020441:Ginkgo biloba / Q000737:chemistry; D065089:Glycoside Hydrolase Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D006586:Hexanes / Q000737:chemistry; D000432:Methanol / Q000737:chemistry; D015394:Molecular Structure; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves; D010946:Plants, Medicinal; D012459:Salicylates / Q000302:isolation & purification / Q000494:pharmacology*; D012997:Solvents / Q000737:chemistry
chemical_list: D000085:Acetates; D065089:Glycoside Hydrolase Inhibitors; D006586:Hexanes; D010936:Plant Extracts; D012459:Salicylates; D012997:Solvents; C112485:ginkgolic acid; C026385:n-hexane; C007650:ethyl acetate; D002725:Chloroform; D020001:1-Butanol; D000432:Methanol