Screening of Antibacterial Agent Against Streptococcus mutans from Natural and Medicinal Plants.

Oral streptococci are major constituents of dental plaques, and their prevalence is closely linked with various pathologic symptoms, such as dental caries. To develop natural anticaries agent, we prepared 309 kinds of plant extracts from 215 species of edible or medical plants, and antibacterial activity of the extracts against Streptococcus mutans JC-2 were evaluated based on 96 well microtiter plate assay and disk paper method, subsequently. Among the tested plant extracts, Ailanthus altissima, Paeonia lactiflora, Rubus phoenicolasius, Aralia continentalis, Quercus acutissima, Persicaria hydropiper and Agrimonia pilosa extracts showed strong antimicrobial activity. Determination of minimal inhibitory concentration (MIC) of the selected seven plant extracts showed that Ailanthus altissima, Persicaria hydropiper and Quercus acutissima extracts ($MIC