摘要:A new cytotoxic substance was isolated following acid treatment of fermented broth of a Streptomyces strain numbered MJ915-WF12. The structure was elucidated by spectroscopic analyses to be 5-dihydro-4-formyl-6-hydroxy-2-hydroxymethyl-6-methyl-2H-pyran. It was thought to be generated by dehydration and ring reformation of the precursor material in cultured broth by acid.