Two New Naphthoquinone-Naphthalene Hybrid Dimers From a Marine-Derived Streptomyces Species.

Two new naphthoquinone-naphthalene hybrid dimers featuring a complex polycyclic fused skeleton, named chimedermycins O (1) and P (2), were isolated from the marine-derived Streptomyces sp. OUCMDZ-4982. Their structures, including the absolute configurations, were established by spectroscopic methods and quantum chemical calculations. These compounds are formed through the coupling of medermycin, a major metabolite produced by the same strain, with naphthalene-1,8-diol derivatives. Both compounds exhibited significant cytotoxicity against two human cancer cell lines (MDA-MB-231 and MGC-803) with IC₅₀ values ranging from 2.30 to 9.78 µM.