Curcumin and capsaicin regulate apoptosis and alleviate intestinal inflammation induced by Clostridioides difficile in vitro

Abstract

Background The dramatic upsurge of Clostridioides difficile infection (CDI) by hypervirulent isolates along with the paucity of effective conventional treatment call for the development of new alternative medicines against CDI. The inhibitory effects of curcumin (CCM) and capsaicin (CAP) were investigated on the activity of toxigenic cell-free supernatants (Tox-S) of C. difficile RT 001, RT 126 and RT 084, and culture-filtrate of C. difficile ATCC 700057. Methods Cell viability of HT-29 cells exposed to varying concentrations of CCM, CAP, C. difficile Tox-S and culture-filtrate was assessed by MTT assay. Anti-inflammatory and anti-apoptotic effects of CCM and CAP were examined by treatment of HT-29 cells with C. difficile Tox-S and culture-filtrate. Expression of BCL-2, SMAD3, NF-κB, TGF-β and TNF-α genes in stimulated HT-29 cells was measured using RT-qPCR. Results C. difficile Tox-S significantly (P < 0.05) reduced the cell viability of HT-29 cells in comparison with untreated cells. Both CAP and CCM significantly (P < 0.05) downregulated the gene expression level of BCL-2, SMAD3, NF-κB and TNF-α in Tox-S treated HT-29 cells. Moreover, the gene expression of TGF-β decreased in Tox-S stimulated HT-29 cells by both CAP and CCM, although these reductions were not significantly different (P > 0.05). Conclusion The results of the present study highlighted that CCM and CAP can modulate the inflammatory response and apoptotic effects induced by Tox-S from different clinical C. difficile strains in vitro. Further studies are required to accurately explore the anti-toxin activity of natural components, and their probable adverse risks in clinical practice.

Psilocybin and Eugenol Reduce Inflammation in Human 3D EpiIntestinal Tissue

“…In addition, we demonstrated here that capsaicin can reduce IFN-γ, and IL-6 levels, which has not been shown before. This builds on previous studies that have shown the anti-inflammatory effects of capsaicin in human colon cancer cell lines [60] and porcine epithelial cell lines [59]. Interestingly, we did not see any major effects of IL-8 levels, which was inhibited, albeit minimally, in previous studies utilizing an LPS-induced inflammatory response in porcine epithelial cells [59].…”

The anti-inflammatory and anti-apoptotic effects of Achillea millefolium L. extracts on Clostridioides difficile ribotype 001 in human intestinal epithelial cells

“…In this study, we used the toxigenic strain of C. difficile RT001 (A + B + ), which was previously characterized in the Department of Anaerobic Bacteriology in Research Institute for Gastroenterology and Liver Diseases in Tehran, Iran [ 34 ]. The strain was cultured on cycloserine-cefoxitin-fructose agar (CCFA, Mast) supplemented with 5% (v/v) sheep blood under anaerobic conditions (85% N 2 , 10% CO 2 and 5% H 2) (Anoxomat® Gas Exchange System, Mart Microbiology BV) at 37 °C for 48–72 h after an alcohol shock treatment [ 35 , 36 ].…”

“…The Tox-S preparation was carried out as described previously [ 36 ]. In brief, the C. difficile RT001 was grown anaerobically in CCFA for 48 h and then used to prepare a bacterial suspension equal to 2 McFarland turbidity standard in 0.85% sterile saline.…”

“…To determine the antibacterial activity of the plant extracts, agar dilution and broth microdilution methods were applied as previously described by Azimirad et al [ 36 ] with minor modifications. Briefly, the range of concentrations used to determine MICs of the extracts was 5-200 µg/mL prepared in the 10% dimethyl sulfoxide (DMSO).…”

“…To evaluate cell viability, a colorimetric assay based on the cleavage of the yellow tetrazolium salt 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) (Sigma-Aldrich, Germany) was performed as previously described [ 36 ]. MTT assay examines the metabolic activity of the cells by measuring the reduction of tetrazolium salts to colored formazan products.…”