Anti-dormant Mycobacterial Activity of Viomellein and Xanthomegnin, Naphthoquinone Dimers Produced by Marine- derived Aspergillus sp.

In the course of a search for anti-dormant mycobacterial substances from marine-derived microorganisms, viomellein (1) and xanthomegnin (2) were re- discovered from the active fraction of the culture of a marine-derived Aspergillus sp. together with rubrosulphin (3) and asteltoxin (4) on the guidance of bioassay-guided separation. In particular, compound 1 showed higher activity against the dormant than against actively growing Mycobacterium bovis BCG and weak activity against M smegmatis. Furthermore, evidence that compound 1 did not directly bind to plasmid DNA suggests its anti-mycobacterial activity differs from its direct chelating effect on the mycobacterial genome.