title: Cholinesterase inhibitory pregnane-type steroidal alkaloids from Sarcococca hookeriana.
abstract: The bioassay-guided phytochemical investigation on Sarcococca hookeriana have resulted in the isolation of four new pregnane-type steriodal alkaloids: hookerianamide-D [(2'E,20S)-20-(N,N-formyl(methyl)amino)-3beta-(3',4'-dimethyl-2'-pentenamido)-5alpha-pregnane] (1), hookerianamide-E [(2'E,20S)-20-(N,N-dimethylamino)-3beta-(senecioylamino)-5alpha-pregn-14-en-2beta-O-acetate] (2), hookerianamide-F [(2'E,20S)-20-(N-methylamino)-3beta-(tigloylamino)-5alpha-pregn-2,14-dien-4-one] (3), and hookerianamide-G [(20S)-20-(N,N-dimethylamino)-3beta-(N-methylbenzamido)-5alpha-pregn-4beta-O-acetate] (4), along with five known alkaloids 5-9. Their structures were determined by spectroscopic analysis. These steroidal alkaloids and chemically derived derivatives of compound 5 have displayed varying degree of inhibitory activities against acetylcholinesterase and butyrylcholinesterase enzymes in a concentration-dependent fashion, with the IC(50) values ranging from 1.5 to 148.2 and 0.6 to 100.2 microM, respectively.
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical Sciences, University of Karachi, Karachi 75270, Pakistan. hej@cyber.net.pk
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Choudhary
authors.forename: Krishna Prasad
authors.initials: KP
authors.lastname: Devkota
authors.forename: Sarfraz Ahmad
authors.initials: SA
authors.lastname: Nawaz
authors.forename: Rosa
authors.initials: R
authors.lastname: Ranjit
authors.lastname: Atta-ur-Rahman
mesh_terms: D000110:Acetylcholinesterase / Q000378:metabolism; D000470:Alkaloids / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001681:Biological Assay; D002091:Butyrylcholinesterase / Q000378:metabolism; D031234:Buxaceae / Q000737:chemistry*; D002800:Cholinesterase Inhibitors / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D020128:Inhibitory Concentration 50; D019906:Nuclear Magnetic Resonance, Biomolecular; D010936:Plant Extracts; D011278:Pregnanes / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D002800:Cholinesterase Inhibitors; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D011278:Pregnanes; D000110:Acetylcholinesterase; D002091:Butyrylcholinesterase