title: Prolyl endopeptidase inhibitors from the leaves of Ginkgo biloba.
abstract: Prolyl endopeptidase (PEP, EC 3.4.21.26) hydrolyzes proline-containing neuropeptides, such as vasopressin, substance P, and thyrotropin-releasing hormone (TRH), and is suggested to participate in learning and memory processes. Ginkgo biloba leaves, upon examination for anti-amnestic constituents as new types of PEP inhibitors, showed significant PEP inhibition. PEP activity-guided fractionation and column chromatography of the MeOH extracts of G. biloba leaves resulted in the isolation of 6-(8'Z-pentadecenyl)salicylic acid (1) and 6-(10'Z-heptadecenyl)salicylic acid (2). The kinetic study indicated that compounds 1 and 2 are non-competitive inhibitors of prolyl endopeptidase with Ki values of 0.87 and 0.80 microM, respectively.
authors.affiliation: College of Environment and Applied Chemistry, Kyung Hee University, Suwon, Korea.
authors.forename: Jung-Han
authors.initials: JH
authors.lastname: Lee
authors.forename: Si-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Kyung-Seok
authors.initials: KS
authors.lastname: Lee
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: Jang
authors.forename: Kyung-Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Tae-Ryong
authors.initials: TR
authors.lastname: Hahn
authors.forename: Young-Sook
authors.initials: YS
authors.lastname: Paik
mesh_terms: D004305:Dose-Response Relationship, Drug; D020441:Ginkgo biloba; D006801:Humans; D020128:Inhibitory Concentration 50; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D018515:Plant Leaves; D000085822:Prolyl Oligopeptidases; D011480:Protease Inhibitors / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D012697:Serine Endopeptidases / Q000187:drug effects*
chemical_list: D010936:Plant Extracts; D011480:Protease Inhibitors; D012697:Serine Endopeptidases; C000705287:PREPL protein, human; D000085822:Prolyl Oligopeptidases