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

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 CD11bþ TLR3þ, CD11bþTLR4þ, CD11bþIL-6þ, CD11bþIL-17þ, CD11bþTNF-aþ, and CD4þCD25þCD62Lþ were assessed by flow cytometry. Results: Our result suggested that NRMOL and FRMOL extracts significantly reduced (p < 0.05) the expression of CD11bþTLR3þ, CD11bþTLR4þ, CD11bþIL-6þ, CD11bþIL-17þ, and CD11bþTNF-aþ subsets. In contrast, NRMOL and FRMOL extracts significantly increased (p < 0.05) the expression of CD4þCD25þCD62Lþ subsets. NRMOL at dose 14 and 42 mg/kg BW was more effective compared to FRMOL in reducing the expression of CD11bþTLR3þ, CD11bþTLR4þ, and CD11bþTNF-aþ 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.