ETHNOPHARMACOLOGICAL RELEVANCE

Ginseng, the root of Panax ginseng C. A. MEYER (Araliaceae), is reputedly known for its nootropic and anti-aging functions and has been widely used to treat various diseases and enhance health for thousands of years in Asia. Recent studies revealed that ginsenoside, responsible for the pharmacological effects of ginseng, can prevent memory loss and improve spatial learning in mice, but underlying mechanisms are still largely unknown. Active neurogenesis in adult hippocampus is closely related to animals' learning and memory ability. The present study aimed to investigate the possible effects of ginsenoside Rd, one of the most effective ingredients in ginseng, on neurogenesis in vivo and in vitro.

MATERIALS AND METHODS

Adult rats and cultured neural stem cells were treated with ginsenoside Rd at different doses, and the changes in the proliferation and differentiation of neural stem cells were examined by immunohistochemistry and immunocytochemistry.

RESULTS

Ginsenoside Rd significantly increased the numbers of BrdU(+) and DCX(+) cells in the hippocampal dentate gyrus but did not affect the ratio of NeuN/BrdU double-labeled cells to the total number of BrdU(+) cells. For cultured neural stem cells, ginsenoside Rd promoted the size and number of neurospheres, increased the number of BrdU(+) and Ki67(+) cells but did not affect the differentiation of neural stem cells into neurons, astrocytes and oligodendrocytes.

CONCLUSIONS

These results indicate that ginsenoside Rd can enhance the proliferation but not affect the differentiation of neural stem cells in vivo and in vitro.