Anticonvulsive and free radical scavenging activities of Gastrodia elata Bl. in kainic acid-treated rats

Gastrodia elata Bl. (GE) is a traditional Chinese herb that is commonly used in Chinese communities to treat convulsive disorders such as epilepsy. The purpose of the present study was to determine the anticonvulsive and free radical activities of GE in rats. In vitro studies were conducted by using brain tissue from 6 male Sprague-Dawley (SD) rats treated with 120 microg/ml of kainic acid (KA), with or without the addition of various concentrations of GE. In vivo studies were conducted in a total of 30 male SD rats divided into 5 groups of 6 rats which were treated as follows: 1) the normal group received an intraperitoneal injection (i.p.) of PBS (Phosphate buffer saline, 1 ml/kg); 2) the control group received KA (12 mg/kg) i.p.; 3) the GE 1.0 group received oral administration of GE 1.0 g/kg 30 min prior to KA administration; 4) the GE 0.5 group received oral administration of GE 0.5 g/kg 30 min prior to KA administration; 5) the PH group received oral administration of phenytoin 20 mg/kg 30 min prior to KA administration. Seizures were verified by behavioral observations, electroencephalograph (EEG) and electromyography (EMG). Lipid peroxide levels in the rat brain, luminol chemiluminescence (CL) and lucigenin-CL in the peripheral blood were measured simultaneously after behavioral observations. The results indicate that GE administration significantly reduced KA-induced lipid peroxide levels in vitro. Oral administration of GE 1.0 g/kg and phenytoin 20 mg/kg significantly reduced counts of wet dog shakes (WDS), paw tremor (PT) and facial myoclonia (FM) in KA-treated rats. In addition, oral administration of GE 1.0 g/kg significantly delayed the onset of WDS, from 30 min in the control group to 46 min in the 0.5 g/kg group, and 63 min in the GE 1.0 g/kg group. A significantly reduced level of lipid peroxides in the rat brain was found in the GE 1.0 g/kg, 0.5 g/kg, and phenytoin 20 mg/kg groups. The GE 1.0 g/kg group showed significant reduction of luminol-CL and lucigenin-CL counts in the peripheral blood compared to the control group. The results of the present study demonstrate that GE has anticonvulsive and free radical scavenging activities. Further studies are needed to determine the clinical effectiveness of GE as an anticonvulsant in humans.

Anticonvulsive and free radical scavenging activities of vanillyl alcohol in ferric chloride-induced epileptic seizures in Sprague-Dawley rats

Vanillyl alcohol (VA) is a component of Gastrodia elata Bl. (GE), which is a traditional Chinese herb widely used to treat convulsive disorders or dizziness. This study examined the role of VA in the anticonvulsive properties of GE in a Sprague-Dawley rat model of epilepsy. The anticonvulsive and free radical scavenging activities of VA were examined after intracortical injection of ferric chloride (100 mM, 8 microl) to induce epileptic seizures. These seizures were verified by behavioral observations and electroencephalographic (EEG) and electromyographic (EMG) recordings. Ferric chloride injection resulted in increased lipid peroxide levels in the ipsilateral and contralateral cerebral cortex, and increased luminol-chemiluminescence (CL) and lucigenin-CL counts in the peripheral blood. Intraperitoneal injection (i.p.) of VA (200 mg/kg or 100 mg/kg) or phenytoin 10 mg/kg prior to ferric chloride administration significantly inhibited wet dog shakes (WDS) and lipid peroxide levels in the bilateral cerebral cortex. VA 200 mg/kg also significantly reduced luminol-CL and lucigenin-CL counts in the peripheral blood, but no significant effect was observed following administration of VA 100 mg/kg or phenytoin. These data indicate that VA has both anticonvulsive and suppressive effects on seizures and lipid peroxidation induced by ferric chloride in rats. Data from the present study also demonstrate that VA has free radical scavenging activities, which may be responsible for its anticonvulsive propertics. This finding is consistent with the results from previous studies that generation of superoxide radical evoked by injection of iron salt into rat brain plays a critical role in ferric chloride-induced seizures. In addition, the results of the present study suggest that the anticonvulsive effect of GE may be attributable, at least in part, to its VA component.

Anticonvulsant effect of Uncaria rhynchophylla (Miq) Jack. in rats with kainic acid-induced epileptic seizure

This study investigated the anticonvulsant effect of Uncaria rhynchophylla (UR) and the physiological mechanisms of its action in rats. A total of 70 male Sprague-Dawley (SD) rats were selected for study. Thirty four of these rats were divided into 5 groups as follows: 1) CONTROL GROUP (n = 6): received intraperitoneal injection (i.p.) of kainic acid (KA, 12 mg/kg); 2) UR1000 group (n = 10), 3) UR500 group (n = 6) 4) UR250 group, received UR 1000, 500, 250 mg/kg i.p. 30 min prior to KA administration, respectively; 5) Contrast group: received carbamazepine 20 mg/kg i.p. 30 min prior to KA administration. Behavior and EEG were monitored from 15 min prior to drug administration to 3 hours after KA administration. The number of wet dog shakes were counted at 10 min intervals throughout the experimental course. The remaining 36 rats were used to measure the lipid peroxide level in the cerebral cortex one hour after KA administration. These rats were divided into 6 groups of 6 rats as follows: 1) Normal group: no treatment was given; 2) CONTROL GROUP: received KA (12 mg/kg) i.p.; 3) UR1000 group, 4) UR500 group, 5) UR250 group, received UR 1000, 500, 250 mg/kg i.p. 30 min prior to KA administration, respectively; 6) Contrast group: received carbamazepine 20 mg/kg i.p. 30 min prior to KA administration. Our results indicated that both UR 1000 and 500 mg/kg decreased the incidence of KA-induced wet dog shakes, no similar effect was observed in the UR 250 mg/kg and carbamazepine 20 mg/kg group. Treatment with UR 1000 mg/kg, 500 mg/kg, or 250 mg/kg and carbamazepine 20 mg/kg decreased KA-induced lipid peroxide level in the cerebral cortex and was dose-dependent. These findings suggest that the anticonvulsant effect of UR possibly results from its suppressive effect on lipid peroxidation in the brain.