Cholinesterase Inhibiting Steroidal Alkaloids from Sarcococca hookeriana Baill. (Buxaceae)

Abstract

The plants of genus Sarcococca (Buxaceae) have an extensive use in folk medicine around Japan, China and South Asia [1]. The popular use of these plants includes the treatment of pain, rheumatism, malaria, skin diseases, gonorrhoea etc [2]. This genus is an important producer of 5α-pregnane type steroidal alkaloids, and most of them have been reported to exhibit anticholinesterase, antibacterial, antitumour, antileishmanial and antiulcer activities [3–6]. During our phytochemical investigation on Sarcococca hookeriana of Nepalese origin, we have isolated 19 steroidal alkaloids, out of which 11 were found to be new. All these compounds were subjected to acetyl- and butyrylcholinesterase inhibitory assay and were shown potent to moderate activities which are comparable to that of standard galanthamine and eserine. Phulchowkiamide (1) was found to be the most potent cholinesterase inhibitor with IC50 0.5 µM for acetylcholinesterase and 0.4 for µM for butyrylcholinesterase. Acknowledgements: We wish to acknowledge Alexander von Humboldt Foundation, Germany and European Commission (Marie Curie, contract No. 21591) for providing post doctoral fellowships to K.P. Devkota and B.N. Lenta, respectively, at Bielefeld University.