title: Screening of crude drug extracts for prolyl endopeptidase inhibitory activity.
abstract: Prolyl endopeptidase (PEP, EC 3.4.21.26) is an enzyme to play a role in metabolism of proline-containing neuropeptides, such as vasopressin, substance P and thyrotropin-releasing hormone (TRH), which were suggested to be involved with learning and memory processes. Then, specific inhibitor of PEP is expected to have antiamnesic effects, and thus we screened forty-six water- and methanol-extracts from crude drugs selected on the basis of traditional Chinese medicine theory, for Flavobacterium prolyl endopeptidase inhibition. Among them, the water-extracts of Rhodiola sacra (IC50, 0.77 microgram/ml) and the methanol-extracts of Lycopodium clavatum (IC50, 1.3 micrograms/ml), Paeonia lactiflora var. trichocarpa (IC50, 5.7 micrograms/ml), Paeonia veitchii (IC50, 2.4 micrograms/ml) and Rhodiola sacra (IC50, 0.67 microgram/ml) showed strong inhibitory activity. In addition, we also examined the PEP inhibitory activity of eleven compounds from Salvia deserta, and found that in addition to a catechol group alpha-hydroxy-para-quinone group may be related to the PEP inhibition.
authors.affiliation: Research Institute for Wakan-Yaku (Traditional Sino-Japanese Medicines), Toyama Medical and Pharmaceutical University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tezuka
authors.forename: W
authors.initials: W
authors.lastname: Fan
authors.forename: R
authors.initials: R
authors.lastname: Kasimu
authors.forename: S
authors.initials: S
authors.lastname: Kadota
mesh_terms: D002681:China; D000432:Methanol; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry*; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D014867:Water
chemical_list: D010936:Plant Extracts; D015842:Serine Proteinase Inhibitors; D014867:Water; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases; D000432:Methanol