Barrier Strengthening and Anti-inflammatory Effect of Cucurbit Fruits on Intestinal Epithelial Cells In-vitro

Background: Acute and chronic infections and inflammations in the gut are highly prevalent in tropical and subtropical countries. Therapeutic measures like Non-Steroidal Anti- Inflammatory Drugs (NSAIDs) often manifest toxic effects. Objective: Some herbal agents (cucurbit fruits) were investigated in-vitro for gut-barrier reinforcement and anti-inflammatory action. Methods: Zonula Occludens (ZO-1), mucin (MUC-2), cyclooxygenases (COX-1 and COX-2) expressions were estimated through ELISA kits. Nitric oxide (NO) was estimated through Griess reaction and adhesion of Lactobacillus rhamnosus (Lrh) to epithelial cells was evaluated microscopically. Results: TNF-α (10 ng/mL) induced inflammatory reaction in epithelial cells (HT-29 and Caco-2) by decreasing ZO-1 proteins. Cells pretreated with cucurbits, when challenged by TNF-α, countered the reduction of ZO-1 proteins, but pretreatment with indomethacin (NSAID) decreased the expression of ZO-1 further. Addition of Lrh to HT-29 cultures, enhanced mucin (MUC-2) production. Cucurbits alone did not enhance MUC-2 production in HT-29 cells but the addition of cucurbits to the combination of Lrh + HT-29 cells significantly increased MUC-2 production and adhesion of Lrh to epithelial cells. TNF-α and LPS treatment to Caco-2 cells increased COX-2 and NO production, but pretreatment with either cucurbits or indomethacin rendered their decrease. Pretreatment with indomethacin decreased COX-1 production in Caco-2 cells but pretreatment with cucurbits yielded enhanced COX-1 expression. Conclusion: This study revealed the potential of cucurbits as non-toxic anti-inflammatory and barrier strengthening agents against gut ailments.