Antibacterial properties of anthraquinones extracted from rhubarb against Aeromonas hydrophila

Antibacterial properties of crude extract from rhubarb and its major bioactive compounds against Aeromonas hydrophila were assayed. Major bioactive compounds (anthraquinone derivatives) in rhubarb collected from different cultivation areas were determined by ultra-performance liquid chromatography (UPLC); the antibacterial activity [minimum inhibitory concentration (MIC)] of rhubarb was positively related to the anthraquinone content (r = 0.9306, P < 0.01). The MIC values of five anthraquinones against A. hydrophila were found to be in the range 50-200 mu g/ml. Action-mode studies showed that anthraquinones (emodin) inhibits cellular functions by binding to cell DNA after penetrating the cell membrane, resulting in cell death. The present study suggests that anthraquinones extracted from rhubarb have potential use as antimicrobials for control of A. hydrophila.