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 µg 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 µg 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 µg 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. Significance and Impact of the Study: An active ingredient of white pepper, piperine showed growth inhibitory activity against multidrug‐resistant (MDR) Gram‐negative bacteria including toxigenic Vibrio cholerae, Pseudomonas aeruginosa and enterohemorrhagic/enteroaggregative Escherichia coli O104 German outbreak strains. It should be noted that piperine did not significantly affect the growth of E. coli isolated from healthy individuals. To the best of our knowledge, this is the first report showing that piperine has an antibacterial activity against toxigenic V. cholerae. This study suggests an approach to exploit safe, edible and readily available white pepper as a potential natural source of antimicrobial agent against enteric and MDR bacteria.