Study on antibacterial active components from Viola yedoensis

Abstract

Study on the antibacterial activity of Viola yedoensis and the antibacterial active compounds. The chemical compositions were isolated by means of solvent extraction, column chromatography on silica gel, sephadex LH-20 and crystallization. The antibacterial activities were tested by Neo-Sensitab disk-diffusion method, nephelometric analysis and plating method. One new compound (4) along with three known compounds were isolated from this plant for the first time and were identified as aesculetin (1), 6,7-dimethoxycoumarin (2), scopoletin (3) and 5-methoxy-7-hydroxymethylcoumarin (4), respectively. All the compounds showed antibacterial and antibactericidal activities at varying degree on Streptococcus Aureas, S. agalactiae, S. uberis, S. dysgalactiae, E. coli and Salmonella, of which 1 was most active with 0.031- 0.313 g x L(-1) of minimal inhibitory concentrations (MIC) and 0.313 - 0.625 g x L(-1) of minimal bactericidal concentrations (MBC). Viola yedoensis has a broad spectrum of antibacterial activity on animal pathogenic bacteria, and coumarins may be the main antibacterial activity ingredients.