Protective effects of novel probiotic strains against LPS-induced inflammation in RAW264.7 macrophages

Plant-based fermented foods offer an underexplored reservoir of probiotic strains with therapeutic potential. In this study, we isolated and screened lactic acid bacteria (LAB) from spontaneously fermented vegetables through a comprehensive in-vitro approach involving stress tolerance assays, antioxidant capacity, adhesion evaluations, and immune modulation studies using RAW 264.7 macrophages. Two standout strains, Lactiplantibacillus plantarum CRT01 (PP724070) and Levilactobacillus brevis CAB20 (PP499280), demonstrated strong resilience to gastrointestinal conditions, robust adhesion to Caco-2 cells, and significant free radical scavenging activity. Notably, both strains reduced reactive oxygen species and modulated LPS-induced inflammatory responses by downregulating TNF-α, IL-1β, IL-6, and IL-12, while enhancing IL-10 expression. This dual antioxidant–immunomodulatory action, along with their ability to exclude pathogens, produce short-chain fatty acids, and exhibit low antibiotic resistance indices, highlights their suitability as non-dairy probiotics for gut-targeted interventions against oxidative stress and inflammation-associated disorders.