Neuroprotective effects of ginseng total saponin and ginsenosides Rb1 and Rg1 on spinal cord neurons in vitro

Spinal cord injury is a major cause of disability and results in many serious physical, psychological, and social difficulties. Numerous studies have shown that traumatic spinal cord injuries (SCI) lead to neuronal loss and axonal degeneration in and around the injury site that cause partial disability or complete paralysis. An important strategy in the treatment of SCI is to promote neuron survival and axon outgrowth, making possible the recovery of neural connections. Using an in vitro survival assay, we have identified ginsenosides Rb1 and Rg1, extracted from ginseng root (Panax ginseng C. A. Meyer), as efficient neuroprotective agents for spinal cord neurons. These compounds protect spinal neurons from excitotoxicity induced by glutamate and kainic acid, as well as oxidative stress induced by H2O2. The neuroprotective effects are dose-dependent. The optimal doses are 20-40 muM for ginsenosides Rb1 and Rg1. The effects are specific for Rb1 and Rg1, since a third ginsenoside, Re, did not exhibit any activity. Ginseng has been used for thousands of years in the treatment of neurological disorders and other diseases in Asia. Ginsenosides Rb1 and Rg1 represent potentially effective therapeutic agents for spinal cord injuries. (C) 2002 Elsevier Science (USA).