Alkaloids including two rare variecolortides from the fungus Aspergillus ruber

Abstract Three new alkaloids, namely, (−)-(S)-variecolortide D (1a), (+)-(R)-variecolortide D (1b) and brevicompanine I (3), along with three known alkaloids (2, 4 and 5) were isolated from Aspergillus ruber WH4-1. Variecolortide D (1) is a racemic natural product composed of anthraquinone and isoechinulin alkaloid, separation of 1 by chiral HPLC, provided two optically pure enantioners (1a and 1b). The structures of all compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature. 2 showed weak inhibitory activity against the production of NO in RAW264.7 cells stimulated by lipopolysaccharide (LPS), with inhibitory rate of 53.2 ± 3.8% at 30 μM.