Concanamycin H from the soil actinomycete Streptomyces sp. R1706-8

The actinomycete strain R1706-8 is isolated from a soil sample collected from the nest of the horned-face bee (Osmia cornifrons) and identified as Streptomyces sp. based upon the results of 16SrRNA sequence analysis. Two concanamycin derivatives obtained from the solid fermentation have been determined by analysis of the infrared, high-resolution electrospray ionization mass spectrometry, 1D and 2D NMR spectra as well as by comparison with literature data. Of the two derivatives, one is a new compound, named concanamycin H, and the other is the known compound, concanamycin G. These compounds are assayed for antibacterial activity, with concanamycins H and G displaying inhibitory activity against Bacillus subtilis (minimum inhibitory concentration = 0.625 µg mL−1).