New Cholinesterase Inhibiting Steroidal Alkaloids from the Leaves of Sarcococca coriacea of Nepalese Origin

Abstract

From the leaves of Sarcococca coriacea two new steroidal alkaloids, epoxynepapakistamine-A [(20S)-20-(N-methylamino)-3β-(tigloylamino)-5α-pregna-16α,17α-epoxy-2β,4β-di-O-acetate] (1), and epoxysarcovagenine-D [(20S)-20-(N-methylamino)-3β-(tigloylamino)-5α-pregna-2-en-16α,17α-epoxy-4-one] (2), and two known compounds funtumafrine C [(20S)-20-(N,N-dimethylamino)-5α-pregna-3-one] (3) and N-methylfuntumine (4) were isolated. Their structures were elucidated on the basis of their spectral properties. The compounds 1, 3 and 4 were found to have cholinesterase inhibitory activity when tested for the inhibition of electric eel acetylcholinesterase and horse serum butyrylcholinesterase. They inhibited both enzymes in a concentration dependent fashion.