Antibacterial, Antioxidant, and Anti-inflammatory Activities of Lacticaseibacillus paracasei Lysates Isolated from Fermented Palm Sap

Paraprobiotics are inactivated microbial cells or cell fractions that confer health benefits to the consumer, and possess the ability to regulate both the adaptive and innate immune systems. They exhibit anti-inflammatory, antiproliferative, antioxidant properties, and antimicrobial activities. The aim of this study is to evaluate these activities of Lacticaseibacillus paracasei lysates isolated from fermented palm sap. The bacterial cell lysates were prepared via sonication, and their antibacterial activity was assessed against three pathogens using agar well diffusion assay. Antioxidant activity was evaluated using DPPH and ABTS radical scavenging assays. Cytotoxicity and anti-inflammatory activity were determined in LPS-stimulated RAW 264.7 cells by measuring nitric oxide production, secretion, and mRNA level of cytokines (IL-1β, IL-6, and IL-10). Among the lysates, L. paracasei T1901 demonstrated the strongest antibacterial activity against Escherichia coli, Bacillus cereus, and Acinetobacter baumannii. Most lysates exhibited potent antioxidant activity, especially T0601 that showed the highest DPPH and ABTS radical scavenging activities. In LPS-stimulated RAW 264.7 cells, the lysates effectively reduced nitric oxide levels and suppressed the production of pro-inflammatory cytokines (IL-1β and IL-6); simultaneously, the lysates enhanced immunosuppressive cytokine IL-10 secretion. Furthermore, no cytotoxic effect was observed in the lysate-treated RAW 264.7 cells. The study highlights the potential of L. paracasei lysates as multifunctional agents with antibacterial, antioxidant, and anti-inflammatory properties. These findings support their application in developing functional foods or therapeutic agents for managing oxidative stress and inflammatory diseases.