Abstracts

Used medicinally for more 2,000 years, ginseng has been shown to have biological activity in a number of systems. The possibility that ginseng may have anticonvulsant activity was first suggested in 2002. The purpose of this study was to test the anticonvulsant activity of three preparations of American ginseng (whole root extract, whole leaves/stems extract and a partially purified extract that concentrates the Rb ginsenosides (Rb extract)) and to identify the active components in the Rb extract., One hour after treatment with normal saline or one of the ginseng preparations, seizures were induced in adult, male, Sprague-Dawley rats with kainic acid (10 mg/kg), pilocarpine (300 mg/kg, preceded by methylscopolamine 1mg/kg sc) or pentylenetetrazol (PTZ, 50 mg/kg ip or 90 mg/kg sc). Time to onset of seizure activity, duration of seizure activity (for PTZ), seizure severity and weight change for KA and pilocarpine were determined for each animal. The brains from animals who had received kainic acid or pilocarpine were examined for neurodegeneration and severe neuronal stress, using fluorojade staining and immunoreactivity for HSP72, respectively., The Rb extract had a dose-dependent anticonvulsant effect in all three models of chemically-induced seizures [ndash] increasing the latency to the seizures, decreasing the seizure score, weight loss and subsequent neuronal damage after pilocarpine and kainic acid, and shortening the seizure duration and reducing mortality after PTZ. In some animals, the Rb extract completely blocked behavioral seizures after administration of kainic acid. The root preparation increased the mortality rate after administration of pilocarpine, but had no other significant effects. The leaves/stems preparation reduced the weight loss after pilocarpine, but had no other significant effects. The individual ginsenosides significantly increased the latency to onset of seizures after administration of kainic acid. Mixtures of purified Rb[sub]1[/sub], Rb[sub]3[/sub] with or without Rd had significant anticonvulsant effects in all three models of acutely-induced seizures demonstrating that the ginsenosides are the active components in the Rb extract., Ginseng extract made from either the root or leaves/stems are ineffective against chemically-induced seizures. A partial purification of the whole extract that concentrates the Rb[sub]1[/sub] and Rb[sub]3[/sub] ginsenosides has significant anticonvulsant properties. Since no one individual ginsenoside accounted for the majority of the activity of the Rb extract, the results suggest that the most effective anticonvulsant product is a combination of ginsenosides from the Rb group. In addition, the Rb extract and the individual ginsenosides have significant neuroprotective activity beyond the reduction in seizure severity and duration., (Supported by the Epilepsy Research Foundation New Therapies Program.)