Abstract
Some diterpenoid anti-blast substances which were found in blast-infected rice leaves and detectable by GLC (OV-17) were isolated and purified by using LC, preparative HPLC and TLCs. These substances were analyzed by GC-MS, MS and HR-MS. The substance 17-3M was identified as S-1 (C20H32O2, Mole. Wt. 304) which was previously reported. The substance 14-6M was analyzed as C20H30O2, Mole. Wt. 302. The molecular weight of the substance 14-7M was 302 and it was assumed as C20H30O2. The substance 12-7M was also detectable by GLC at similar retention time with other substances and distinctly different from Oryzalexins which were formerly reported. The analyses of the fractions from HPLC indicated the existence of several derivatives which could be novel substances.
