Abstract
A new isoflavonoid was isolated from Erythrina poeppigiana (Leguminosae), and was characterized as 3, 9-dihydroxy-10-γ, γdimethylallyl-6a, 11a-dehydropterocarpan based on extensive spectroscopic studies. Antibacterial activity of the isoflavonoid against Gram-positive oral bacteria was estimated by determining minimum inhibitory concentrations. The isoflavonoid inhibited the growth of mutans streptococci and other oral streptococci at a concentration range of 6.25-12.5μ g/mL, and Actinomyces and Lactobacillus at<1.56-6.25μg/mL. The inhibitory activity against mutans streptococci was based on a bactericidal action. The new compound is a leading candidate compound for the prophylaxis of oral-related infectious diseases caused by Gram-positive bacteria.
