Viopudial, a Hypotensive and Smooth Muscle Antispasmodic from Viburnum opulus

Summary The administration of viopudial, a Viburnum opulus component, produces bradycardia, hypotension, and some decrease in myocardial contractility. Experimental evidence indicates that viopudial's mechanism of action is partly due to its effects on cholinesterase. In vitro demonstrations of a competitive inhibitory effect on both acetylcholinesterase and butyrylcholinesterase showed viopudial to be relatively weak when compared to the known potent inhibitor, physostigmine. Additional mechanistic effects, such as a direct musculotrophic action, may also be responsible for the overall activity. The authors are grateful to Dr. A. H. Nathan and Mr. C. V. Vanderkolk of the Upjohn Company, Kalamazoo, MI, for extractions. This research was supported by NIH Grants GM 461, GM 33,888 and AM 07147.