Antibacterial property of isoflavonoids isolated from Erythrina variegata against cariogenic oral bacteria

• Published in: Phytomedicine (Stuttgart) 2003, Vol.10 (5), p.427-433
• Main Authors: Sato, M., Tanaka, H., Fujiwara, S., Hirata, M., Yamaguchi, R., Etoh, H., Tokuda, C.
• Format: Article
• Language: English
• Subjects: Actinomyces - drug effects; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; antibacterial activity; Antibacterial agents; Beans; Cariogenic bacteria; Chemical properties; Dental Caries - microbiology; Erythrina; Erythrina - chemistry; Erythrina variegata; glucose incorporation; Health aspects; Heterocyclic Compounds, 4 or More Rings; Isoflavones; Isoflavones - chemistry; Isoflavones - isolation & purification; Isoflavones - pharmacology; isoflavonoids; Lactobacillus - drug effects; Legumes; Microbial Sensitivity Tests; Mimosaceae; Molecular Structure; Oral health; Physiological aspects; Streptococcus - drug effects
• ISSN: 0944-7113; 1618-095X
• DOI: 10.1078/0944-7113-00225

The antibacterial property of 7 compounds, isolated from Erythrina variegata(Leguminosae) by repeated silica gel column chromatography, against cariogenic oral bacteria was investigated. Extensive spectroscopic study revealed that all were isoflavonoids. Among them, 3,9-dihydroxy-2,10-di(γ,γ-dimethylallyl)-6a,11a-dehydropterocarpan (erycristagallin) showed the highest antibacterial activity against mutans streptococci, other oral streptococci, Actinomycesand Lactobacillus species with a minimum inhibitory concentration (MIC) range of 1.56–6.25 μg/ml, followed by 3,6a-dihydroxy-9-methoxy-2,10-di(γ,γ-dimethylallyl)pterocarpan (erystagallinA) and 9-hydroxy-3-methoxy-2-γ,γ-dimethylallylpterocarpan (orientanol B) (MIC range: 3.13–12.5 μg/ml). The antibacterial effect of erycristagallin to mutans streptococci was based on a bactericidal action. Erycristagallin (6.25 μg/ml: MIC) completely inhibited incorporation of radio-labelled thymidine into Streptococcus mutanscells. Incorporation of radio-labelled glucose into bacterial cells was also strongly inhibited at MIC, and 1/2 MIC of the compound reduced the incorporation approximately by half. The findings indicate that erycristagallin has a potential as potent phytochemical agent for prevention of dental caries by inhibiting the growth of cariogenic bacteria and by interfering with incorporation of glucose responsible for production of organic acids.