Gypenosides (GP), the saponin extract derived from the Gynostemma pentaphyllum Makino, a widely reputed medicinal plant in China, has been reported to have some neuroprotective effects. We used a rat model of chronic cerebral hypoperfusion to investigate the protective effects of GP on the cortex and hippocampal CA1 region and the underlying mechanisms for its inhibition of cognitive decline. Daily doses of 100 and 200 mg/kg GP were orally administered to adult male Sprague-Dawley rats for 61 days after inducing cerebral hypoperfusion experimentally, and spatial learning and memory were assessed using the Morris water maze. Antioxidative capability was measured biochemically. The levels of lipid peroxidation and oxidative DNA damage were assessed by immunohistochemical staining for 4-hydroxynonenal and 8-hydroxy-2'-deoxyguanosine, respectively. Activated astrocytes were assessed by immunohistochemical staining and western blotting with GFAP antibodies. Rats receiving 200 mg/kg GP had better spatial learning and memory than saline-treated rats. GP 200 mg/kg/day were found to markedly enhance antioxidant abilities, decrease lipid peroxide products and oxidative DNA damage, and reduce the activation of inflammatory astrocytes. However, GP 100 mg/kg had no significant effects. GP may have therapeutic potential for the treatment of dementia induced by chronic cerebral hypoperfusion and further evaluation is warranted.

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A series of silicon dioxide supported titania by the impregnation method for transesterification of diethyl oxalate (DEO) and phenol was carried out under the facile catalytic condition in the liquid phase at 453 k in the atmospheric pressure. Within different TiO2loadings ranging from 1% to 20%, 10% TiO2/SiO2performed best, giving 49.5% conversion of DEO and the total 100% selectivity to ethyl phenyl oxalate (EPO) and diethyl oxalate (DPO). To further study the relationship between catalytic performances and the catalysts structure, several characterization methods, analysis of X-ray diffraction (XRD), Raman spectroscopy measurement and FTIR of adsorbed pyridine studies were utilized. The results of XRD and Raman, showed amorphous structure of TiO2on SiO2below the 10% loading and crystalline form of TiO2phase on SiO2above the 10% loading. In addition, FTIR of adsorbed pyridine studies illuminated the Lewis-type acid sites were responsible for transesterification between DEO and phenol.