Woodfordia fruticosa fermented with lactic acid bacteria impact on foodborne pathogens adhesion and cytokine production in HT-29 cells

Abstract

Introduction: The study into the interplay between foodborne pathogens and human health, particularly their effects on intestinal cells, is crucial. The importance of lactic acid bacteria (LAB) in promoting a healthy balance of gut microbiota, inhibiting harmful bacteria, and supporting overall gastrointestinal health is becoming more apparent.

Methods: Our study delved into the impact of fermenting Woodfordia fruticosa (WF), a plant known for its antimicrobial properties against gastrointestinal pathogens, with LAB. We focused on the influence of this fermentation process on the binding of foodborne pathogens to the gut lining and cytokine production, aiming to enhance gut health and control foodborne infections in HT-29 cells.

Results and discussion: Post-fermentation, the WF exhibited improved antimicrobial effects when combined with different LAB strains. Remarkably, the LAB-fermented WF (WFLC) substantially decreased the attachment of pathogens such as L. monocytogenes (6.87% ± 0.33%) and V. parahaemolyticus (6.07% ± 0.50%) in comparison to the unfermented control. Furthermore, WFLC was found to upregulate IL-6 production in the presence of pathogens like E. coli O157:H7 (10.6%) and L. monocytogenes (19%), suggesting it may activate immune responses. Thus, LAB-fermented WF emerges as a potential novel strategy for fighting foodborne pathogens, although additional studies are warranted to thoroughly elucidate WF's phytochemical profile and its contribution to these beneficial outcomes.

Keywords: HT-29; Woodfordia fruticosa; fermentation; foodborne pathogens; lactic acid bacteria.

Figure 1

Antibacterial activity of WF extracts at various ethanol concentrations (A). Inhibitory effects of LAB-fermented WF on foodborne pathogens [Escherichia coli O157:H7 (ATCC 43895) (B), Listeria monocytogenes (ATCC 7644) (C), Salmonella typhimurium (ATCC 35987) (D), and Vibrio parahaemolyticus (ATCC 35118) (E)]. Values are expressed as mean ± SEM. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001. ET, 50% ethanol solution; WF, Woodfordia fruticosa; WFLR, Woodfordia fruticosa flower fermented with Lacticaseibacillus rhamnosus ATCC9595; WFLA, Woodfordia fruticosa flower fermented with Lacticaseibacillus acidophilus ATCC 4356; WFLC, Woodfordia fruticosa flower fermented with Lacticaseibacillus casei ATCC 7469; WFLB, Woodfordia fruticosa flower fermented with Lactobacillus buchneri KCTC5064.

Figure 2

Impact of LAB-fermented WF on HT-29 cell viability with and without foodborne pathogens at 24 and 48 h. (A) HT-29 cell viability in the absence of foodborne pathogens. CT refers to only HT-29 cells. (B) HT-29 cell viability after exposure to Escherichia coli O157:H7 (ATCC 43895) (CT) alone and in combination with LAB-fermented WF. (C) HT-29 cell viability after exposure to Listeria monocytogenes (ATCC 7644) (CT) alone and in combination with LAB-fermented WF. (D) HT-29 cell viability after exposure to Salmonella typhimurium (ATCC 35987) (CT) alone and in combination with LAB-fermented WF. (E) HT-29 cell viability after exposure to Vibrio parahaemolyticus (ATCC 35118) (CT) alone and in combination with LAB-fermented WF. Values are expressed as mean ± SEM. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001. WFLR, Woodfordia fruticosa flower fermented with Lacticaseibacillus rhamnosus ATCC9595; WFLA, Woodfordia fruticosa flower fermented with Lactobacillus acidophilus ATCC 4356; WFLC, Woodfordia fruticosa flower fermented with Lactobacillus casei ATCC 7469; WFLB, Woodfordia fruticosa flower fermented with Lactobacillus buchneri KCTC5064.

Figure 3

Foodborne pathogen adhesion inhibition on HT-29 cells by LAB-fermented WF. (A) Adhesion efficiency in HT-29 cells after exposure to Escherichia coli O157:H7 (ATCC 43895) (CT) alone and in combination with LAB-fermented WF. (B) Adhesion efficiency in HT-29 cells after exposure to Listeria monocytogenes (ATCC 7644) (CT) alone and in combination with LAB-fermented WF. (C) Adhesion efficiency in HT-29 cells after exposure to Salmonella typhimurium (ATCC 35987) (CT) alone and in combination with LAB-fermented WF. (D) Adhesion efficiency in HT-29 cells after exposure to Vibrio parahaemolyticus (ATCC 35118) (CT) alone and in combination with LAB-fermented WF. Values are expressed as mean ± SEM. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001. WFLR, Woodfordia fruticosa flower fermented with Lacticaseibacillus rhamnosus ATCC9595; WFLA, Woodfordia fruticosa flower fermented with Lactobacillus acidophilus ATCC 4356; WFLC, Woodfordia fruticosa flower fermented with Lactobacillus casei ATCC 7469; WFLB, Woodfordia fruticosa flower fermented with Lactobacillus buchneri KCTC5064.

Figure 4

Cytokine production by HT-29 cells in response to LAB-fermented WF. (A) IL-6. (B) IL-10. (C) IL-1β. (D) TNF-a. Values are expressed as mean ± SEM. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001. WFLR, Woodfordia fruticosa flower fermented with Lacticaseibacillus rhamnosus ATCC9595; WFLA, Woodfordia fruticosa flower fermented with Lactobacillus acidophilus ATCC 4356; WFLC, Woodfordia fruticosa flower fermented with Lactobacillus casei ATCC 7469; WFLB, Woodfordia fruticosa flower fermented with Lactobacillus buchneri KCTC5064. CT, no treatment.

Figure 5

IL-6 gene expression in HT-29 cells exposed to LAB-fermented WF and foodborne pathogens. (A) IL-6 gene expression of LAB-fermented WF to HT-29 cells after exposure to Escherichia coli O157:H7 (ATCC 43895) (CT) alone and in combination with LAB-fermented WF. (B) IL-6 gene expression of LAB-fermented WF to HT-29 cells after exposure to Listeria monocytogenes (ATCC 7644) (CT) alone and in combination with LAB-fermented WF. (C) IL-6 gene expression of LAB-fermented WF to HT-29 cells after exposure to Salmonella typhimurium (ATCC 35987) (CT) alone and in combination with LAB-fermented WF. (D) IL-6 gene expression of LAB-fermented WF to HT-29 cells after exposure to Vibrio parahaemolyticus (ATCC 35118) (CT) alone and in combination with LAB-fermented WF. Values are expressed as mean ± SEM. ^*p < 0.05, ^**p < 0.01, ^***p < 0.001. WFLR, Woodfordia fruticosa flower fermented with Lacticaseibacillus rhamnosus ATCC9595; WFLA, Woodfordia fruticosa flower fermented with Lactobacillus acidophilus ATCC 4356; WFLC, Woodfordia fruticosa flower fermented with Lactobacillus casei ATCC 7469; WFLB, Woodfordia fruticosa flower fermented with Lactobacillus buchneri KCTC5064.