Anti-oral microbial activity of isoflavonoids in root bark of Ormosia monosperma

From the root bark of Ormosia monosperma, 10 isoflavonoids including two new compounds 7,4'-dihydroxy-6",6"-dimethylpyrano-(2",3":5,6)-8-(3-methyl-1,3- butadienyl)isoflavone, named ormosidin, and dalbergion 4'-O-beta-D-glucopyranoside, were isolated. These structures were confirmed by spectroscopic analysis. 2,3-Dihydroauriculatin, one of the compounds isolated, showed moderate activities against oral-microbial organisms (Streptococcus mutans, Prophyromonas gingivalis and Actinomyces actinomycetemcomitans).