Testing the Anti-Inflammatory Effects of Dietary Phytochemicals in Intestinal Inflammation Models

Ulcerative colitis (UC) is an immune-mediated chronic disease characterized by colonic inflammation, ulcers and erosion. Medications benefit 50% UC patients and have serious adverse effects. Therefore, safe and efficient molecules are needed as stan-alone drugs or in combination with available treatments to increase therapy potency and minimize adverse effects. Dietary phytochemicals are a good source of potential UC treatments, since adherence to diets rich in fruit and vegetables, including the Mediterranean diet, improved UC symptoms. Salvia rosmarinus (rosemary) is a “Generally Recognized As Safe” Mediterranean culinary and medicinal herb abundant in diterpenes, understudied antioxidant and anti-inflammatory phytochemicals. Carnosic acid (CA) and carnosol (CL) are the most abundant diterpenes in rosemary, however less abundant diterpenes are understudied. Fractions that excluded CA and CL from the diterpene-rich oil-soluble rosemary extract, VivOX® 40, activated the antioxidant transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) in a luciferase reporter assay. Yet pure CA was the most potent NRF2 activator. NRF2 negatively represses the pro-inflammatory transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ƙB) which promotes transcription of neutrophil gelatinase associated lipocalin (NGAL), an antibacterial protein positively correlated with UC severity. Accordingly, we hypothesized that CA would upregulate the NRF2 and decrease inflammation in intestinal inflammation models. We used UC patient-derived colonoids and HT-29 colon cancer cells to study NRF2 modulation by CA and NRF2 activation positive control sulforaphane (SFN). With qPCR, western blot, and ELISA techniques we observed that CA and SFN decreased secretion of pro-inflammatory cytokines in tumor necrosis factor (TNF) stimulated colonoids. CA and SFN also upregulated the mRNA expression of NRF2 target genes SOD2 and HMOX1 in TNF-stimulated colonoids, undifferentiated and sodium butyrate differentiated HT-29 cells. CA pre-treatment upregulated LCN2 (NGAL encoding gene) mRNA expression and decreased NGAL protein expression and secretion while SFN downregulated transcription and translation. In HT-29 cells, CA and SFN downregulated LCN2 mRNA expression and NGAL protein expression and secretion. Together, the data suggested that CA and SFN can potentially decrease inflammation at the molecular level in colon epithelial cells prompting further investigation into their mechanism of action alone and in combination with UC drugs.

Author dc:creator

• Rocío Rivera Rodriguez (24400151)

• Anti-inflammatory dietary phytochemicals
• Ulcerative colitis patient-derived colonoids as pharmacological testing platform
• NGAL modulation in colon epithelial cells

Statement dc:rights

• In Copyright
• Open Access after 2028-05-01

DOI dc:identifier

https://doi.org/10.25417/uic.32995205.v1

OAI identifier oai:identifier

oai:figshare.com:article/32995205