Neuritogenic Activity of Epigallocatechin Gallate and Curcumin Combination on Rat Adrenal Pheochromocytoma Cells

Abstract

Plant phytochemicals are important neuroprotective agents which mainly act as antioxidants by scavenging stress -induced free radicals in the brain. Phytochemicals from medicinal plants including epigallocatechin gallate and curcumin play a vital role in maintaining the brain's chemical balance by targeting neurotrophins. Many studies have shown that both curcumin, the yellow pigment in turmeric, and (-)-epigallocatechin gallate (EGCG) in green tea possess anti-inflammatory, anti-oxidative stress, tumor reduction, and neuroprotective properties against many neurodegenerative conditions. In this study, the neuritogenic potential of EGCG and curcumin combination treatment were evaluated on PC-12 Adh cells. The neuritogenic potential of EGCG and curcumin combined concentrations were evaluated by the cell differentiation analysis on xCELLigence real time cell analysis system (RTCA-DP) according to the changing in cell index (CI) values. Neurite outgrowth was observed with immunofluorescence staining and neurite lengths were measured. Nerve growth factor (NGF) was used as positive control. Also GAP-43 and beta-tubulin mRNA expression levels, which are associated with neurite outgrowth promotion, were determined with RT-PCR method. According to our results, 100 nM EGCG and curcumin combination was significantly induced neurite outgrowth and also particularly up-regulated GAP-43 mRNA expression level on PC-12 Adh cells. The present study supports the notion that polyphenols such as EGCG and curcumin have potential to be effective as neuroprotective agents for the treatment of neurodegenerative diseases.