Anti-inflammatory effects of salicarinins A, B, and C from Lythrum salicaria L. in a porcine intestinal epithelial cell model

Post-weaning diarrhea (PWD), primarily caused by enterotoxigenic Escherichia coli (ETEC), is a major gastrointestinal disorder in piglets and is characterized by intestinal inflammation. The overuse of antibiotics in PWD treatment has contributed to antimicrobial resistance, highlighting the need for alternative strategies. Hydrolysable tannin-rich plants, such as Purple loosestrife ( Lythrum salicaria L.), are historically recognized for their anti-diarrheal properties and present a promising alternative. This study aimed to investigate the phytochemical composition of Lythrum salicaria L. herb aqueous extract (LSH) and assess the anti-inflammatory potential of LSH and its isolated compounds. Using a colorimetric method, we determined the total tannin content (TTC) as 270.90±3.37 μg gallic acid equivalents (GAE)/mg. Tannins represented the major polyphenol fraction in LSH. The total polyphenol content (TPC) was 279.06±4.17 μg GAE/mg. Compounds were identified using chromatographic and spectrometric techniques. Column chromatography led to the isolation of hydrolysable tannins, including vescalagin, castalagin, and salicarinins A, B, and C, enabling further investigation of their bioactivity. To model an inflammatory response similar to ETEC infection, we stimulated cells with Class B CpG oligonucleotide (ODN 2006), a synthetic DNA fragment that mimics bacterial DNA. Notably, treatment with salicarinins A, B, and C at concentrations of 10-20 μM, 5-20 μM, and 20 μM, respectively, significantly suppressed IL-8 secretion in the intestinal porcine epithelial cell line IPEC-J2 without affecting its viability. These findings suggest that LSH could help mitigate intestinal inflammation associated with ETEC-induced PWD and serve as a natural alternative to antibiotics in pig nutrition, supporting the need for further in vivo studies to confirm its therapeutic potential in swine nutrition. Funding Project financially supported by Polish National Science Centre research grant OPUS LAP UMO-2020/39/I/NZ7/02547. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany