An unusual glucoalkaloid has been crystallized from the title cactus plant. Acid employed in the usual alkaloid extraction schemes decomposed the new plant. Actu employed in the usual altation extraction schemes decomposed the newnonphenolic altation (deprocereine) into a new phenolic altaloid (deglucopterocereine)and glucose. β-Glucosidase also hydrolyzed the glu compound exhibited significant cytotoxicity in the 9 KB system.