Effects of N-demethylation of pamamycins on aerial mycelium-inducing and growth inhibition activities

Using a combination of ODS and NH2 HPLCs, we isolated new pamamycin derivat ives from the culture broth of Streptomyces alboniger IFO 12738. MS spectro scopy showed that their structures were de-N-methylpamamycins with the aid of labeled compounds prepared in a methionine-methyl-d(3) feeding culture o f S. alboniger. De-N-methylpamamycins had stronger aerial mycelium-inducing activity and weaker growth-inhibition activity than the corresponding pama mycin with the same alkyl group arrangement.