Indicanines B and C, two isoflavonoid derivatives from the root bark of Erythrina indica

In addition to two known compounds, 5,4'-di-O-methylalpinumisoflavone and cajanin, a new 3-phenylcoumarin metabolite, named indicanine B, and a new isoflavone derivative, named indicanine C, were isolated from the root bark of Erythrina indica. By means of spectroscopic analysis, the structures of the new compounds were characterized as 4-hydroxy-3-(4'-hydroxyphenyl)-5-methoxy-2",2"-dimethylpyrano 5",6":6,7] coumarin and 4'-hydroxy-5-methoxy-2",2"-dimethylpyrano 5",6":6,7] isoflavone, respectively. The 13C-NMR data of cajanin and the in vitro antimicrobial spectrum and potencies of the isolated compounds are also reported.