Punicalagin Inhibits Salmonella Virulence Factors and Has Anti-Quorum-Sensing Potential

Abstract

bPunicalagin, an essential component of pomegranate rind, has been demonstrated to possess antimicrobial activity against several food-borne pathogens, but its activity on the virulence of pathogens and its anti-quorum-sensing (anti-QS) potential have been rarely reported. This study investigated the efficacy of subinhibitory concentrations of punicalagin on Salmonella virulence factors and QS systems. A broth microdilution method was used to determine the MICs of punicalagin for 10 Salmonella strains. Motility assay and quantitative reverse transcription (RT)-PCR were performed to evaluate the effects of punicalagin on the virulence attributes and QS-related genes of Salmonella. The MICs of punicalagin for several Salmonella strains ranged from 250 to 1,000 g/ml. Motility assays showed that punicalagin, at 1/16؋ MIC and 1/32؋ MIC, significantly decreased bacterial swimming and swarming motility, which corresponded to downregulation of the motility-related genes (fliA, fliY, fljB, flhC, and fimD) in RT-PCR assays. RT-PCR also revealed that punicalagin downregulated the expression of most of the selected genes involved in Salmonella virulence. Moreover, a QS inhibition assay indicated that punicalagin dose dependently inhibited the production of violacein by Chromobacterium violaceum and repressed the expression of QS-related genes (sdiA and srgE) in Salmonella. In addition, punicalagin significantly reduced Salmonella invasion of colonic cells (P < 0.01) with no impact on adhesion. These findings suggest that punicalagin has the potential to be developed as an alternative or supplemental agent for prevention of Salmonella infection.

Exploring the anti‐quorum sensing activity of a d‐limonene nanoemulsion for Escherichia coli O157:H7

“…These results are consistent with other reports, wherein a considerable reduction in biofilm formation of P. aeruginosa was observed after QS inhibitor treatment . It was found that different signal molecules excreted from plants, such as furanones and punicalagin, played important roles in inhibiting QS‐based swimming and swarming motility. Thus, repressed swimming and swarming motility of E. coli caused by d ‐limonene nanoemulsion further verified the anti‐QS property of d ‐limonene nanoemulsion.…”

Antibacterial activity of polyphenol-rich pomegranate peel extract against Cronobacter sakazakii

“…Some of the polyphenolic compounds identified in the PoP extract have been shown to inhibit Gram negative bacteria, including species of Enterobacteriaceae. For example, the ellagitannin punicalagin was reported to inhibit 10 strains of S. enterica at MICs ranging between 0.25 and 1.0 mg/mL [33] , six S. enterica strains at MICs between 0.6 and 0.8 mg/mL and six E. coli strains at MICs of 1.0 to 3.2 mg/ mL. [31] The antibacterial effects of ellagic acid, the second most abundant polyphenolic compound in the extract, have been studied in detail against the bacterium Helicobacter pylori.…”

Detection and characterization of multidrug‐resistant Salmonella enterica serovar Infantis as an emerging threat in poultry farms of Faisalabad, Pakistan

“…For swimming assay, LB medium contained 0Á25% (w/v) agar, 0Á5% (w/v) glucose in 25 g l À1 of LB broth. The agar plates were inoculated with a single isolated colony at the centre and incubated at 37°C for 10 h as previously described (Li et al 2014). The difference in swimming and swarming activities among MDR, XDR and PDR isolates, was tested by analysis of variance at 5% level of significance using Microsoft Excel (2016) Software.…”