A new daidzein derivative from endophytic Streptomyces sp. YIM 65408.

A new daidzein derivative, 1″-O-methyl-8-hydroxymethyl-daidzein (1) was isolated from Streptomyces sp. YIM 65408 in soybean powder containing medium. The structure was elucidated on the basis of extensive 1D and 2D NMR as well as HR-ESI-MS spectroscopic analyses. The radical-scavenging activity and cytotoxicity of compound 1 were also investigated, and 1 was found to be more active than daidzein in the 2,2-diphenyl-1-picrylhydrazyl method with IC50 at 0.60 mmol/L, but no cytotoxicity of 1 against HL-60, SMMC-7721, A-549, MCF-7 and SW480 cell lines was shown. The possible biosynthesis pathway from daidzein (2) to compound 1 was proposed.