Lactobacillus plantarum FNCC 0137 fermented red Moringa oleifera exhibits protective effects in mice challenged with Salmonella typhi via TLR3/TLR4 inhibition and down-regulation of proinflammatory cytokines

Abstract

Background: Salmonella typhi is a foodborne pathogenic bacterium that threatens health. S. typhi infection exacerbated the antibiotic resistance problem that needs alternative strategies. Moringa oleifera possesses anti-inflammatory and antimicrobial effects. However, there is a lack of information about the pharmacological value of red M. oleifera. The fermentation of red M. oleifera leaves extract (RMOL) is expected to add to its nutritional value.

Objective: The present study aimed to evaluate non-fermented RMOL (NRMOL) and fermented RMOL (FRMOL) effects on S. typhi infection in mice.

Materials and methods: Female Balb/C mice were randomly divided into eight groups. The treatment groups were orally administered with NRMOL or FRMOL at doses 14, 42, and 84 mg/kg BW during the 28 days experimental period. Then S. typhi was introduced to mice through intraperitoneal injection except in the healthy groups. The NRMOL or FRMOL administration was continued for the next seven days. Cells that expressed CD11b⁺ TLR3⁺, CD11b⁺TLR4⁺, CD11b⁺IL-6⁺, CD11b⁺IL-17⁺, CD11b⁺TNF-a⁺, and CD4⁺CD25⁺CD62L⁺ were assessed by flow cytometry.

Results: Our result suggested that NRMOL and FRMOL extracts significantly reduced (p <0.05) the expression of CD11b⁺TLR3⁺, CD11b⁺TLR4⁺, CD11b⁺IL-6⁺, CD11b⁺IL-17⁺, and CD11b⁺TNF-α⁺ subsets. In contrast, NRMOL and FRMOL extracts significantly increased (p <0.05) the expression of CD4⁺CD25⁺CD62L⁺ subsets. NRMOL at dose 14 and 42 mg/kg BW was more effective compared to FRMOL in reducing the expression of CD11b⁺TLR3⁺, CD11b⁺TLR4⁺, and CD11b⁺TNF-α⁺ subsets.

Conclusion: Our findings demonstrated that NRMOL and FRMOL extracts could be promising agents for protection against S. typhi infection via modulation of TLR3/TLR4, regulatory T cells, and proinflammatory cytokines.

Keywords: Inflammation; Lactobacillus; Red moringa; Regulatory T cells; Salmonella.

Fig. 1

Effect of NRMOL and FRMOL on CD11b+TLR3+ and CD11b+TLR4+ subsets in mice challenged with S. typhi. (A) The dot plot analysis of CD11b+TLR3+ subsets in spleen. (B) NRMOL reduced CD11b⁺TLR3⁺ subsets more effective FRMOL on mice challenged with S. typhi. (C) The dot plot analysis of CD11b⁺TLR4⁺ subsets in spleen. (D) NRMOL reduced CD11b⁺TLR4⁺ subsets more effective FRMOL on mice challenged with S. typhi. The different letter considered significantly different between each group (p < 0.05) by post hoc test using Tukey's HSD test. HM = Healthy Mice; NRMOL = Non-fermented red M. oleifera Leaves Extract; FRMOL = Fermented red M. oleifera Leaves Extract; NRMOL-14 = S. typhi + NRMOL 14 mg/kg BW; NRMOL-42 = S. typhi + NRMOL 42 mg/kg BW; NRMOL-84 = S. typhi + NRMOL 84 mg/kg BW; FRMOL-14 = S. typhi + FRMOL 14 mg/kg BW; FRMOL-42 = S. typhi + FRMOL 42 mg/kg BW; and FRMOL-84 = S. typhi + FRMOL 84 mg/kg BW.

Fig. 2

Effect of non-fermented MOLE and fermented MOLE on proinflammatory generation in mice challenged with S. typhi. (A) The dot plot analysis of CD11b⁺IL-6⁺ subsets in spleen. (B) NRMOL reduced CD11b⁺IL-6⁺ subsets more effective FRMOL on mice challenged with S. typhi. (C) The dot plot analysis of CD11b⁺IL-17⁺ subsets in spleen. (D) NRMOL and FRMOL reduced CD11b⁺IL-17⁺ subsets on mice challenged with S. typhi. (E) The dot plot analysis of CD11b⁺ TNF-α + subsets in spleen. (F) NRMOL reduced CD11b⁺TNF-α⁺ subsets more effective FRMOL on mice challenged with S. typhi. The different letter considered significantly different between each group (p < 0.05) by post hoc test using Tukey's HSD test. HM = Healthy Mice; NRMOL = Non-fermented red M. oleifera Leaves Extract; FRMOL = Fermented red M. oleifera Leaves Extract; NRMOL-14 = S. typhi + NRMOL 14 mg/kg BW; NRMOL-42 = S. typhi + NRMOL 42 mg/kg BW; NRMOL-84 = S. typhi + NRMOL 84 mg/kg BW; FRMOL-14 = S. typhi + FRMOL 14 mg/kg BW; FRMOL-42 = S. typhi + FRMOL 42 mg/kg BW; and FRMOL-84 = S. typhi + FRMOL 84 mg/kg BW.

Fig. 3

Effect of NRMOL and FRMOL on CD4⁺CD25⁺CD62L⁺ subsets in mice challenged with S. typhi. (A) The dot plot analysis of CD4⁺CD25⁺CD62L⁺ subsets in spleen. (B) NRMOL and FRMOL increased CD4⁺CD25⁺CD62L⁺ subsets on mice challenged with S. typhi. The different letter considered significantly different between each group (p < 0.05) by post hoc test using Tukey's HSD test. HM = Healthy Mice; NRMOL = Non-fermented red M. oleifera Leaves Extract; FRMOL = Fermented red M. oleifera Leaves Extract; NRMOL-14 = S. typhi + NRMOL 14 mg/kg BW; NRMOL-42 = S. typhi + NRMOL 42 mg/kg BW; NRMOL-84 = S. typhi + NRMOL 84 mg/kg BW; FRMOL-14 = S. typhi + FRMOL 14 mg/kg BW; FRMOL-42 = S. typhi + FRMOL 42 mg/kg BW; and FRMOL-84 = S. typhi + FRMOL 84 mg/kg BW.