title: New diterpene isopimara-7,15-dien-19-oic acid and its prolyl endopeptidase inhibitory activity.
abstract: The ethanolic extract of the bulbs of Fritillaria imperialis was subjected to fractionation by solvent-solvent extraction. The nonpolar fraction showed inhibitory activity against prolyl endopeptidase (PEP) (EC.3.4.21.26), a large intracellular enzyme that preferentially hydrolyze proline-containing oligopeptidase at the carboxylic side of a prolyl residue. We have isolated a diterpenoid isopimara-7,15-dien-19-oic acid (1) from the nonpolar fraction of F. imperialis, and on methylation of compound 1, a methylester 2 was obtained which is a known compound previously isolated from Fritillaria thunbergii. The present article describes the isolation and structural elucidation of isopimara-7,15-dien-19-oic acid (1) by single-crystal X-ray diffraction techniques along with its prolyl endopeptidase inhibitory activity.
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical Sciences, University of Karachi, Karachi-75270, Pakistan.
authors.lastname: Atta-ur-Rahman
authors.forename: Muhammad Nadeem
authors.initials: MN
authors.lastname: Akhtar
authors.forename: Muhammad Iqbal
authors.initials: MI
authors.lastname: Choudhary
authors.forename: Yoshisuke
authors.initials: Y
authors.lastname: Tsuda
authors.forename: Amsha
authors.initials: A
authors.lastname: Yasin
authors.forename: Bilge
authors.initials: B
authors.lastname: Sener
authors.forename: Masood
authors.initials: M
authors.lastname: Parvez
mesh_terms: D004224:Diterpenes / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D031410:Fritillaria; D006801:Humans; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D000085822:Prolyl Oligopeptidases; D012697:Serine Endopeptidases / Q000187:drug effects*; D014961:X-Ray Diffraction
chemical_list: D004224:Diterpenes; D004791:Enzyme Inhibitors; D010936:Plant Extracts; C500031:isopimara-7,15-dien-19-oic acid; D012697:Serine Endopeptidases; C000705287:PREPL protein, human; D000085822:Prolyl Oligopeptidases