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Cholinesterase inhibitory pregnane-type steroidal alkaloids from Sarcococca hookeriana
M Iqbal Choudhary1, Krishna Prasad Devkota, Sarfraz Ahmad Nawaz
1H.E.J. Research Institute of Chemistry, International Center for Chemical Sciences, University of Karachi, Karachi 75270, Pakistan. hej@cyber.net.pk
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.
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