Anticonvulsive and free radical scavenging actions of two herbs, Uncaria rhynchophylla (MIQ) Jack and Gastrodia elata Bl., in kainic acid-treated rats

Uncaria rhynchophylla (Miq.) Jack (UR) and Gastrodia elata BI. (GE) are tra ditional Chinese herbs that are usually used in combination to treat convul sive disorders, such as epilepsy, in China. The aim of this study was to co mpare the anticonvulsive and free radical scavenging activities of UR alone and. UR in combination with GE in rats. For the in vitro studies, brain ti ssues from 6 male Sprague-Dawley (SD) rats were treated with 120 mu g/ml ka inic acid (KA), with or without varied concentrations of UR or UR plus GE. For the in vivo studies. male SD rats (6 per group) received intraperitonea l (i.p.) injection of KA 12 mg/kg to induce epileptic seizures and generati on of free radicals, with or without oral administration of UR 1 g/kg alone or UR 1 g/kg plus GE 1 g/kg. Epileptic seizures were verified by behaviora l observations, and electroencephalography (EEG) and electromyography (EMG) recordings. These results showed that UR alone decreased KA-induced lipid peroxide levels in vitro, whereas UR plus GE did not produce a greater effe ct than UR alone. UR significantly reduced counts of wet dog shakes (WDS), paw tremor (PT) and facial myoclonia (FM) in KA-treated rats and significan tly delayed the onset time of WDS, from 27 min in the control group to 40 m in in the UR group. UR plus GE did not inhibit seizures more effectively th an UR alone, but did further prolong the onset time of WDS to 63 min (P < 0 .05 vs. UR alone). UR alone reduced the levels of free radicals in vivo, as measured by lipid peroxidation in the brain and luminol-chemiluminescence (CL) counts and lucigenin-CL counts in the peripheral whole blood, but the combination of GE and UR did not reduce free radical levels more markedly t han UR alone. In conclusion, our results indicate that UR has anticonvulsiv e and free radical scavenging activities, and UR combined with GE exhibit g reater inhibition on the onset time of WDS than UR alone. These findings su ggest that the anticonvulsive effects of UR and GE may be synergistic. Howe ver. the mechanism of interaction between UR and GE remains unknown.