MARCHANTIN-A TRIMETHYL ETHER - ITS MOLECULAR-STRUCTURE AND TUBOCURARINE-LIKE SKELETAL-MUSCLE RELAXATION ACTIVITY

Marchantin A is a novel macrocyclic bis(bibenzyl)ether isolated from t he liverwort Marchantia species. An X-ray study of its derivative, mar chantin A trimethyl ether, revealed that the molecule possesses convex and concave surfaces, with a central hole on the concave surface. The centroid-centroid separations of opposing benzene rings are 8.80 and 4.55 Angstrom. A pharmacological study showed that the skeletal muscle relaxation activity is about 3.5 times less potent than that of d-tub ocurarine. A comparison of the X-ray structure of marchantin A. trimet hyl ether and that of O,O',N'-trimethyltubocurarine reported by Sobell ct al. revealed that the molecules share almost the same macrocyclic bis(bibenzyl)ether skeleton structure, portions of which may therefore be crucial for the skeletal muscle relaxation activity.