| Oren-gedoku-to (Huanglian-Jie-Du-Tang, OGT), a classical Traditional Chinese Medicine prescription, consists of four herbs, namely, Coptidis rhizoma, Scutellariae radix, Phellodendri cortex and Gardeniae fructus. It has been clinically used to treat chronic inflammatory and ulcerative diseases for many years. Its pharmacological actions such as anti-inflammatory and anti-ulcer had been studied. However, sufficient experimental effects of OGT on improving learning and memory have not yet been done.In this paper, chemical components in OGT extract were qualitatively analyzed by three-dimensional high performance liquid chromatography (HPLC). And the content of Berberine, Palmatine, Baicalin and Geniposide was quantitatively determined by HPLC. In the present pharmacological research, improving effects of OGT extract on learning and memory in animals subjected to cerebral ischemia were investigated. Furthermore, the mechanisms of OGT extract on improving learning and memory were studied.The analytical results of components showed that there were at least fourteen components such as Berberine, Palmatine, Magnoflorine, Epiberberine, Jateorrhizine, Coptisine, Columbamine, Baicalin, Baicalein, Wogonin, Oroxylin A, Oroxylin A 7-O-glucuronide, Skullcapflavone II and Geniposide in OGT extract. The content of Berberine, Palmatine, Baicalin gnd Geniposide in OGT extract was 81.6 mg/g, 22.2 mg/g, 37.0 mg/g and 46.3 mg/g, respectively.The pharmacological research showed that spontaneous locomotor activity and explorative activity in novel environment in mice subjected to cerebral ischemia were not affected by OGT extract (2.0, 4.0 and 8.0 g/kg, ig). In step-down task, the step-down latency in cerebral ischemic mice was significantly prolonged by OGT extract (2.0, 4.0 and 8.0 g/kg, ig) and the step-down errors were markedly decreased by OGT extract (4.0 and 8.0 g/kg, ig). In step-through task, the step-through errors in cerebral ischemic mice were notably decreased by OGT extract (2.0, 4.0 and 8.0 g/kg, ig). In Morris water maze test, the latency of escaping onto platform in training trial in cerebral ischemic mice was remarkably shortened by OGT (2.0, 4.0 and 8.0 g/kg, ig). The percentage of crossing theformer platform quadrant in probe trial was significantly increased by OGT extract (4.0 and 8.0 g/kg, ig). The experimental results suggested that OGT extract could improve the learning and memory deficits induced by cerebral ischemia in mice.In addition, the survival time in mice subjected to bilateral common carotid artery occlusion or treated with NaNO2 (800 mg/g, ip) was significantly prolonged by OGT extract. The sleeping latency induced by KCN (4.5 mg/kg, ip) in mice was not affected by OGT extract (2.0, 4.0 and 8.0 g/kg, ig), but the sleeping duration was significantly shortened by OGT extract (2.0, 4.0 and 8.0 g/kg, ig). The speed of consuming oxygen in mice under the condition of closed normobaric hypoxia was not affected by OGT extract (2.0, 4.0 and 8.0 g/kg, ig), while the survival time in mice was significantly prolonged by OGT extract due to improving the ability of using oxygen. The results suggested that OGT had effects against the acute hypoxia and cerebral ischemia to a certain extent.The cerebral blood flow (CBF) of cortex and hippocampus in rat was significantly increased after rat was administered OGT extract (125, 250 and 500 mg/kg) by fermoral intravenous injection.The malondialdehyde (MDA) content of cortex and hippocampus in hypoxia mice induced by KCN (6.0 mg/kg, ip) was significantly reduced by OGT extract. In addition, the MDA content of the whole brain, cortex and hippocampus in mice subjected to cerebral ischemia was reduced by OGT extract. The experimental results suggested that OGT had strong anti-oxidation effects.Furthermore, the activity of antioxidase in cortex and hippocampus in cerebral ischemic mice, including superoxide dismutase, catalase and glutathione peroxidase was significantly raised by OGT extract. The glutathione content of cortex and hippocampus in cerebral...
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