Chronic inflammation is a common factor in the pathological processes of multiple human diseases. EPS-LM, an exopolysaccharide (EPS) from the Cordyceps sinensis fungus Cs-HK1, has shown notable anti-inflammatory activities in previous studies. This study aimed to investigate the major signaling events mediating the anti-inflammatory effects of EPS-LM in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cell culture. EPS-LM treatment significantly reduced LPS-induced production of pro-inflammatory mediators, including nitric oxide (NO) and reactive oxygen species (ROS). It also suppressed the expression levels of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88), subsequently delaying the translocation of nuclear factor-kappa B (NF-κB) to the nucleus. Additionally, co-immunoprecipitation (Co-IP) experiments demonstrated that EPS-LM inhibited the binding of TLR4 to MyD88. The ability of EPS-LM to inhibit the TLR4/MyD88/NF-κB pathway, coupled with its capacity to reduce oxidative stress, underscores its multifaceted anti-inflammatory effects. These effects render EPS-LM as a promising candidate for the comprehensive management of various inflammatory and oxidative stress-related conditions, protecting against cell damage.

The association constant for calcium binding to hydroxybenzoates in aqueous 0.16 M NaCl at 25 °C was found electrochemically to have the value Kass = 280 mol L-1 with ΔHo = -51 kJ mol-1, ΔSo = -122 J mol-1 K-1 for the 2-isomer (salicylate), Kass = 7 mol L-1 with ΔHo = -39 kJ mol-1, ΔSo = -116 J mol-1 K-1 for the 3-isomer, and Kass = 8 mol L-1 with ΔHo = -51 kJ mol-1, ΔSo = -155 J mol-1 K-1 for the 4-isomer. The 3- and 4-isomers were found more efficient as antioxidants than the 2-isomer in decreasing oxygen consumption rate in a peroxidating methyl linoleate emulsion and less sensitive to presence of calcium. All isomers were found prooxidative for iron-catalyzed initiation of oxidation due to enhanced radical formation as shown by electron spin resonance spectroscopy. Calcium salicylate was found to have low solubility with a solubility product Ksp = 4.49·10-6 based on activity with ΔHo = 67 kJ mol-1, ΔSo = 123 J mol-1 K-1 for dissolution in water, when corrected for the strong complex formation. Calcium in food and beverages may thus lower antioxidant activity of plant phenols through complexation or by precipitation.