New okaramine congeners, okamines J, K, L, M and related compounds, from Penicillium simplicissimum ATCC 90288

Four new okaramine congeners, okaramines J, K, L and M, were isolated from ohara fermented with Penicillium simplicissimum ATCC 90288, together with f ive biogenetically related compounds, cyclo (8a-(alpha,alpha-dimethylallyl) -L-Trp-8a-(alpha,alpha-dimethylallyl)-L-Trp), cycle (N-8-(alpha,alpha-dimet hylallyl)-L-Trp -6a'-(alpha,alpha- dimethylallyl)-L-Trp), cyclo (L-Trp-L-Tr p), cycle (6a'-(alpha,alpha-dimethylallyl)-L-Trp-L-Trp), and cycle (N-8(alp ha,alpha-dimethylallyl)-L-Trp-L-Trp). Their structures were elucidated on t he basis of spectroscopic methods. The new okaramines exhibited no insectic idal activity against silkworms.