New pregnane-type their steroidal alkaloids from Sarcococca saligna and cholinesterase inhibitory activity

Five new steroidal alkaloids, 5,14-dehydro-N-a-demethylsaracodine [3beta-N-a-methyl-20S-N-h-acetyl-N-b-methylamino-pregn-5,14-diene] (1), 14-dehydro-N-a-demethylsaracodine [3beta-N-a-methyl-20S-N-b-acetyl-N-b-methylamino-5alpha-pregn-14-ene] (2), 16-dehydrosarcorine [(20S)-20-(N,N-dimethylamino)-3beta-(N-a-acetylamido)-5alpha-pregn-16-ene] (3), 2,3-dehydrosarsalignone [(20S)-20-(N,N-dimethylamino)-3beta-(tigloylamino)-pregn-2,5-diene-4-one] (4), and 14,15-dehydrosarcovagine-D [(20S)-20-(N,N-dimethylamino)-3beta-(tigloylamino)-5alpha-pregn-2, 14-diene-4-one] (5), were isolated from the ethanolic extract of Sarcococca saligna, along with two known bases, sarcovagenine-C (6) and salignarine-C (7). Their structures were elucidated on the basis of spectroscopic methods. All seven compounds were found to possess cholinesterase inhibitory potential in a concentration-dependent manner with the IC50 values ranging from 12.5 to 32.2 muM against acetylcholinesterase and from 1.25 to 32.2 muM against butyrylcholinesterase. (C) 2004 Elsevier Inc. All rights reserved.