Cholinesterase Inhibiting and Antiplasmodial Steroidal Alkaloids from Sarcococca hookeriana

Bioguided phytochemical investigation of Sarcococca hookeriana with respect to the cholinesterase enzyme inhibitory assay yielded two new pregnane-type steriodal alkaloids hookerianamide H (1) and hookerianamide 1 (2), along with three known alkaloids N-a-methylepipachysamine D (3), sarcovagine C (4) and dictyophlebine (5). Their structures were determined with the aid of extensive spectroscopic analysis. All compounds showed good inhibitory activities against the enzymes acetylcholinesterase (IC50 2.9-34.1 mu M) and butyryleholinesterase (IC50 0.3-3.6/mu M). These compounds also showed moderate antiplasmodial activity (IC50 2.4-10.3 mu m) against the Plasmodium falciparum chloroquine resistant W2 strain.