Novel Phytoalexins (Oryzalexins A, B and C) Isolated from Rice Blast Leaves Infected with Pyricularia oryzae. Part II: Structural Studies of Oryzalexins

Abstract

Oryzalexins A, B and C, isolated from rice leaves infected with P. oryzae as a group of novel phytoalexins, were confirmed to be (+)-sandaracopimaradiene derivatives by chemical and spectroscopic studies, i.e. A: 3-oxy-7-oxo- (I); B: 3-oxo-7-oxy- (II) and C: 3, 7-dioxo-(+)-sandaracopimaradiene (III).