Curcumin Protects against Monosodium Glutamate Neurotoxicity and Decreasing NMDA2B and mGluR5 Expression in Rat Hippocampus.

Background: Monosodium glutamate (MSG) is a flavor enhancer used in food industries. MSG is well documented to induce neurotoxicity. Curcumin (CUR) reportedly possesses beneficial effects against various neurotoxic insults. Hence, this present study has been designed to evaluate the neuroprotective effect of curcumin on MSG-induced neurotoxicity in rats.

Methods: Thirty-two male Wister rats were divided into four groups (n=8): Control group, MSG group, CUR group and MSG + CUR group. CUR (Curcumin 150 mg/kg, orally) was given day after day for four weeks along with MSG (4 mg/kg, orally). After 4 weeks, rats were sacrificed and brain hippocampus was isolated immediately on ice. Inflammatory marker TNFα and acetylcholinesterase (AChE) activity (marker for cholinergic function) were estimated. Gene expressions of metabotropic glutamate receptor 5 (mGluR5) and N-methyl-D-aspartate receptor 2B (NMDA2B) along with glutamate concentration were assessed.

Results: Treatment with CUR significantly attenuated AChE activity and TNFα in MSG-treated animals. The anti-inflammatory properties of CUR may be responsible for this observed neuroprotective action. A possible role of CUR to attenuate both glutamate level and gene expression of NMDA2B and mGLUR5 in brain hippocampus was established when compared to MSG group.

Conclusion: We concluded that CUR as flavor enhancer protects against MSG-induced neurotoxicity in rats.