STUDIES ON MACROCYCLIC LACTONE ANTIBIOTICS. VII

STRUCTURE OF A PHYTOTOXIN "RHIZOXIN" PRODUCED BY RHIZOPUS CHINENSIS

Abstract

A new 16-membered macrolide designated as rhizoxin was isolated as a toxin produced by Rhizopus chinensis, the causal agent of rice seedling blight. The skeletal structure was determined by detailed NMR spectroscopic investigation of this compound and of its derivatives. Rhizoxin induced at a concentration of 10 ng/ml abnormal swelling of rice seedling roots, which is one of the characteristic symptoms of this disease. This compound also exhibited potent antifungal activity but little effect against bacteria.