Lotus Root Extract Stimulates BDNF Gene Expression Through Potential Mechanism Depending on HO-1 Activity in C6 Glioma Cells.

Polyphenolic compounds have been suggested to be involved in the preservation of neural function via the production of neurotrophic factors in the brain. The nonedible joint part of lotus root (a rhizome of Nelumbo nucifera) has been reported to contain large amounts of polyphenolic compounds and, therefore, is expected to improve neural function by stimulating the production of brain-derived neurotrophic factor (BDNF) in glial cells. The effect of the aqueous extract prepared from the joint part of lotus root on BDNF gene expression was examined in C6 glioma cells as an in vitro model. This extract was shown to increase BDNF messenger ribonucleic acid (mRNA) levels to the elevation of HO-1 mRNA levels in the glioma cells, but failed to cause the elevation of BDNF mRNA levels in the cells pretreated with a HO-1 antisense oligodeoxynucleotide (ODN) or an HO-1 enzyme inhibitor zinc protoporphyrin (ZnPP). These findings strongly suggest that the aqueous extract prepared from the nonedible joint part of lotus root might be able to stimulate BDNF gene expression by enhancing HO-1 activity in the glioma cells, proposing the possibility that the joint part of lotus root might potentially improve neural function through the stimulation of BDNF production in glial cells.