Bhimamycin A to approximately E and bhimanone: isolation, structure elucidation and biological activity of novel quinone antibiotics from a terrestrial Streptomycete

From the ethyl acetate extract of a terrestrial Streptomycete isolate, five new quinone antibiotics, bhimamycin A (2a), B (2b), C (3c), D (5a), E (7) and the new tetralone bhimanone (8) were isolated together with the known microbial products chrysophanol (1a), aloesaponarin II (1b), 3,8-dihydroxy-1-methylanthraquinone-2-carboxylic acid (1c), adenosine, 2'-deoxyadenosine, phenylacetamide, and 2-(p-hydroxyphenyl)ethanol. The structures of these natural products were deduced from the spectral data and confirmed by comparison with related compounds from the literature and by synthesis.