Neuroprotective bibenzyl glycosides of Stemona tuberosa roots

Three new bibenzyl glycosides characterized as stilbostemin B 3'-beta-D-glucopyranoside ( 1), stilbostemin H 3'-beta-D-glucopyranoside ( 2), and stilbostemin I 2 ''-beta-D-glucopyranoside ( 3) were isolated from the roots of Stemona tuberosa. All three bibenzyl glycosides significantly protected human neuroblastoma SH-SY5Y cells from 6-hydroxydopamine-induced neurotoxicity.