Piperine, an active ingredient of white pepper, suppresses the growth of multidrug-resistant toxigenic Vibrio cholerae and other pathogenic bacteria

Emergence and rapid spread of multidrug-resistant (MDR) bacteria including Vibrio cholerae are a global public health issue. Much attention has been paid to natural compounds, such as spices and herbs to find novel antimicrobial compounds as they are considered to be cheaper alternatives to develop as a drug. Here, we show that methanol extract of white pepper could inhibit the growth of V. cholerae O1 El Tor variant, responsible for the recent outbreaks/epidemics. Furthermore, we demonstrate for the first time that piperine, the major component of white pepper, showed a dose-dependent bactericidal effect on V. cholerae growth irrespective of their biotypes and serogroups in the presence of 200 and 300 mu g ml(-1) of piperine, respectively. Piperine also inhibited the growth of MDR strains of Pseudomonas aeruginosa, Escherichia coli isolated from poultry and enterohemorrhagic/enteroaggregative E. coli O104 in the presence of 200 mu g ml(-1). Interestingly, we did not observe any significant inhibitory effect of piperine on E. coli strains isolated from healthy person even up to 200 mu g ml(-1). Our data suggest that piperine could be a novel antimicrobial agent in therapeutic and preventive applications against infections caused by pathogenic bacteria including MDR strains.