Crepidamycins A-E, pyranonaphthoquinones from endophytic Streptomyces sp. MG-F-1 of Dendrobium crepidatum by the co-culture strategy.

On the basis of the co-culture strategy, five previously undescribed S-bridged pyranonaphthoquinones, crepidamycins A-E (1-5) and five known analogues (6-10) were isolated from a medicinal plant endophytic Streptomyces sp. MG-F-1 in Dendrobium crepidatum with Bacillus cereus MG-1. The structures and absolute configurations of 1-5 were elucidated by the interpretation of data from detailed spectroscopic analysis and electronic circular dichroism spectra, together with consideration of the biogenetic origins.