Antibacterial activity of mulberry extracts and purified fractions against oral pathogenic bacteria

Objectives: This study aimed to isolate antibacterial compounds active against periodontopathic bacteria from mulberry (Morus alba) leaves. Methods: The acetone-soluble fraction of mulberry leaves was extracted from the oil layer by oil/water separation. The extract was purified using silica gel open-column chromatography. The minimum inhibitory concentration (MIC) of the crude extract or purified fractions against Porphyromonas gingivalis was measured at each step. Results: The MIC of the crude extract against P. gingivalis was 62.5-125 mu g/mL. The fractions showing activity against P. gingivalis were designated Cf K and Cf P. The MICs of Cf K against P. gingivalis, Fusobacterium nucleatum, Prevotella intermedia, and Streptococcus mutans were 6.25 mu g/mL, 25 mu g/mL, 12.5 mu g/mL, and 12.5 mu g/mL, respectively. In contrast, the MICs of Cf P against P. gingivalis, F. nucleatum, P. intermedia, and S. mutans were 25.0 mu g/mL, >50 mu g/mL, 50 mu g/mL, and 12.5-25.0 mu g/mL, respectively. Conclusions: Mulberry leaves contain antibacterial components against periodontopathic bacteria such as P. gingivalis, F. nucleatum, and P. intermedia.