Effects of Free Curcumin on Inflammatory Responses and Cell Viability in Escherichia coli-Challenged BV2 Microglial Cells.

Introduction: Neuroinflammation is a key component of several neurological disorders and may be triggered by bacterial infections and systemic inflammatory conditions. Microglial cells play a central role in regulating inflammatory responses in the central nervous system, producing cytokines and reactive nitrogen species in response to pathogenic stimuli. Curcumin, a polyphenolic compound derived from Curcuma longa, has been extensively studied in this context. The present study evaluated the effects of free curcumin on inflammatory parameters in BV2 microglial cells challenged with Escherichia coli (E.coli). Objectives: To assess the effects of free curcumin on nitrite production, IL-6 levels, and cell viability in BV2 microglial cells challenged with Escherichia coli. Methods: BV2 microglial cells were pretreated with free curcumin at concentrations of 1 μM, 5 μM, and 10 μM for 1 hour before bacterial challenge. Subsequently, cells were exposed to Escherichia coli at a multiplicity of infection (MOI) of 10 and incubated for 24 hours. Following incubation, IL-6 levels and nitrite production were measured, and cell viability was assessed using the resazurin assay. Statistical Analysis: Data were analyzed using one-way ANOVA followed by an appropriate post hoc multiple-comparison test. Differences were considered statistically significant at p < 0.05. Results: Exposure to Escherichia coli increased nitrite production in BV2 cells. Curcumin treatment significantly decreased nitrite levels compared with the E. coli group (p < 0.05). IL-6 levels were reduced in curcumin-treated groups at all tested concentrations. Cell viability was preserved across all experimental groups, except for the death control group. Conclusion: Curcumin treatment was associated with a significant reduction in nitrite production in BV2 cells challenged with E. coli, while cell viability remained preserved. IL-6 levels were also reduced in curcumin-treated groups.