Neuroprotective effects of Ginkgo biloba extract and Ginkgolide B against oxygen-glucose deprivation/reoxygenation and glucose injury in a new in vitro multicellular network model / 医学前沿

Acute ischemic stroke (AIS), as the third leading cause of death worldwide, is characterized by its high incidence, mortality rate, high incurred disability rate, and frequent reoccurrence. The neuroprotective effects of Ginkgo biloba extract (GBE) against several cerebral diseases have been reported in previous studies, but the underlying mechanisms of action are still unclear. Using a novel in vitro rat cortical capillary endothelial cell-astrocyte-neuron network model, we investigated the neuroprotective effects of GBE and one of its important constituents, Ginkgolide B (GB), against oxygen-glucose deprivation/reoxygenation and glucose (OGD/R) injury. In this model, rat cortical capillary endothelial cells, astrocytes, and neurons were cocultured so that they could be synchronously observed in the same system. Pretreatment with GBE or GB increased the neuron cell viability, ameliorated cell injury, and inhibited the cell apoptotic rate through Bax and Bcl-2 expression regulation after OGD/R injury. Furthermore, GBE or GB pretreatment enhanced the transendothelial electrical resistance of capillary endothelial monolayers, reduced the endothelial permeability coefficients for sodium fluorescein (Na-F), and increased the expression levels of tight junction proteins, namely, ZO-1 and occludin, in endothelial cells. Results demonstrated the preventive effects of GBE on neuronal cell death and enhancement of the function of brain capillary endothelial monolayers after OGD/R injury in vitro; thus, GBE could be used as an effective neuroprotective agent for AIS/reperfusion, with GB as one of its significant constituents.

Microorganisms of special herb-glycosidases and their fermentation, enzyme properties / 生物工程学报

Herb-glycosides are main active elements of Zhongcaoyao (Chinese traditional medicines, Chinese medical herbs). However, the herb-glycoside structures are not optimal active structure for the human bodies. After orally taken up, the herb-glycosides of Zhongcaoyao could be changed into other more active structures by the digestive system such as enzymes and intestinal microorganisms; then degraded and absorbed in the human body and play the real role of pharmic effect; but only a small amount could be changed and controlled by circadian state of the human body. If this biochange of herb-glycosides to more active structures in vivo was finished in vitro, it is very useful for the development of the Chinese traditional medicines, new plant medicines, health food, and function cosmetics. To biotransformate herb-glycosides to more active structure, this paper introduced the studies of author's team on the new microorganism isolation of the special herb-glycosidases and enzyme fermentation, the special enzyme purification and characterization.