CURARE-LIKE ACTION OF MAGNOCURARINE ISOLATED FROM MAGNOLIA OBOVATA

Abstract

On the pharmacological investigation of principal constituents of magnoliaceous plants growing in Japan, there are no scientific reports except that of Sasaki (1). He succeeded in separating some substances, in a laquer-like state, which possess curariform activity, from the alcoholic extracts of a few plants of this family, including Magnolia obovata, Thunb. From the bark of Magnolia obovata Thunb. (Japanese name “Hohnoki”) Tomita and Inubushi (2) have recently isolated a new alkaloid, named it magnocurarine and determined its chemical structure. It was found to be N-methyl coclaurine `methyl hydroxide, which resembles one half of the molecular structure of d-tubocurarine (see Fig. 1). Magnocurarine is almost colorless, microscopic, prismatic crystals, melting at 200°C with effervescence and is readily soluble in water, but insoluble in most of organic solvents. We have decided to study in some detail the properties of magnocurarine chloride (MC) and compared the curare-like action of this substance with that of d-tubocurarine chloride (TC) and of decamethonium iodide (C10). We had planned the comparative studies of the curare-like action of MC and TC but because of the lack of TC we have been compelled to use C10 instead of TC in some experiments.