Antibacterial phenylpropanoid glycosides from Paulownia tomentosa Steud.

The butanol extract of Paulownia tomentosa stem showed antibacterial activity against Staphylococcus aureus (SG511, 285 and 503), Streptococcus pyogenes (A308 and A77) and Streptococcus faecium MD8b etc. The most active compound of the extract was identified to be campneoside I, which had a minimal inhibitory concentration (MIC) of 150 micrograms/ml against Streptococcus and Staphylococcus species. From such antibacterial activity, the methoxy group of campneoside I was postulated to be the essential element for the antibacterial activity.