Effects of growth media modulation on cytotoxicity, antioxidant and anti-inflammatory activities of postbiotic metabolites produced by Lactiplantibacillus plantarum I-UL4

Lactiplantibacillus plantarum I-UL4 produces various postbiotic metabolites with known anticancer and antioxidant activities, but its anti-inflammatory effect remains unclear. In this study, we compared postbiotic metabolites produced by L. plantarum I-UL4 with commercial de Man, Rogosa and Sharpe (MRS) medium (PMM) and a reported refined formulation (PMF) for their volatile compound profiles, cytotoxicity, antioxidant and anti-inflammatory effects on LPS-stimulated THP-1 leukaemia cells. Volatile compound profiling was performed by GC–MS and cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium Bromide assay. Subsequently, antioxidant effects were determined for cellular reactive oxygen species (ROS) levels (DCFDA assay) and inflammatory responses at the gene (nuclear factor kappa B, cyclooxygenase-2, IL-6, IL-18, TNF-α, IL-1β and IL-10) and protein levels via qPCR and cytokine antibody arrays. GC–MS analysis revealed that L. plantarum I-UL4 produced distinct volatile compound profiles from MRS and refined formulation media. Nonetheless, lactic acid predominating (≈ 89–92% peak area), alongside other unique bioactive compounds in PMM and PMF, as compared to MRS and the refined formulation media. Notably, PMM was more cytotoxic, with the lowest IC 50 (2.57 ± 0.2) at 72 h. Interestingly, both PMF and PMM reduced ROS levels at 48 h. Importantly, PMF showed significantly stronger ( P < 0.05) anti-inflammatory effects by inhibiting nuclear factor kappa B and cyclooxygenase-2 and simultaneously modulating both pro- and anti-inflammatory cytokine genes and protein expression compared with PMM, suggesting that PMF could be a promising biotic preparation for modulating inflammation-related diseases. In conclusion, this study reveals how fermentation media affect the volatile composition, bioactivity and functionality of postbiotic metabolites, including cytotoxicity, antioxidant and anti-inflammatory activities.