In Vitro Antimicrobial and Immunomodulatory Activity of Trans-4-Hydroxycinnamic Acid Against Bovine Mastitis-Associated Bacteria

Background/Objectives: Bovine mastitis is a major economic and health challenge in the dairy industry, heavily dependent on antibiotics and increasingly complicated by antimicrobial resistance (AMR). This study evaluated the in vitro therapeutic efficacy of trans-4-hydroxycinnamic acid (4-HCA) as a novel alternative therapeutic agent on bovine mammary epithelial cells (bMECs). Specifically, the objectives were to assess the biofilm-forming capacity of mastitis-associated bacterial isolates, determine the antibacterial and bactericidal profile of 4-HCA, and investigate its immunomodulatory effects on infected bMECs using quantitative real-time PCR (qRT-PCR).