Protective effects of Dendrobium nobile Lindl. alkaloids on amyloid beta(25–35)-induced neuronal injury

Dendrobium nobile Lindl.alkaloids（DNLA）,the active ingredients of a traditional Chinese medicine Dendrobium,have been shown to have anti-oxidative effects,anti-inflammatory action,and protective effect on neurons against oxygen-glucose deprivation.However,it is not clear whether DNLA reduces amyloid-beta（Aβ）-induced neuronal injury.In this study,cortical neurons were treated with DNLA at different concentrations（0.025,0.25,and 2.5 mg/L）for 24 hours,followed by administration of Aβ（25-35）（10μM）.Aβ（25-35） treatments increased cell injury as determined by the leakage of lactate dehydrogenase,which was accompanied by chromatin condensation and mitochondrial tumefaction.The damage caused by Aβ（25-35） on these cellular properties was markedly attenuated when cells were pretreated with DNLA.Treatment with Aβ（25-35）down-regulated the expressions of postsynaptic density-95 mRNA and decreased the protein expression of synaptophysin and postsynaptic density-95,all changes were significantly reduced by pretreatment of cells with DNLA.These findings suggest that DNLA reduces the cytotoxicity induced by Aβ（25-35） in rat primary cultured neurons.The protective mechanism that DNLA confers on the synaptic integrity of cultured neurons might be mediated,at least in part,through the upregulation of neurogenesis related proteins synaptophysin and postsynaptic density-95.

Extraction Process Optimization and Anti-oxidant Activity of Total Flavonoids in Dendrobium nobile Lindl.

[Objectives]To improve the yield of flavonoids from Dendrobium nobile Lindl.[Methods]On the basis of four single-factor experiments of solid/liquid ratio,extraction temperature,extraction time and ethanol volume fraction,the ultrasonic-assisted extraction process of total flavonoids from D.nobile Lindl.was optimized using quadratic general rotary unitized design,and the in-vitro anti-oxidant activity of the flavonoids extracted was evaluated preliminarily.[Results]The optimized extraction process for flavonoids in D.nobile Lindl.was as follows:extraction time 10 min,solid/liquid ratio 1∶15(g∶mL),extraction temperature 75℃and ethanol volume fraction 90%.According to the revised optimal process,6 repeated experiments were carried out,and the average yield of flavonoids was(0.5515±0.0004)mg/g,consistent with the predicted value of the model.The results of anti-oxidation experiment show that the flavonoids extracted from D.nobile Lindl.have better scavenging effect on ABTS and DPPH free radicals,and the scavenging activity is proportional to the mass concentration of the extract.[Conclusions]The optimized extraction process for flavonoids from D.nobile Lindl.is reasonable and feasible,and the flavonoids in D.nobile Lindl.have strong antioxidant activity.

Dendrobium nobile Lindl:A Review on Its Chemical Constituents and Pharmacological Effects

Dendrobium nobile Lindl (D. nobile), a well-known precious herb, has a long history of use as a medicine and health food in China. Phytochemically, D. nobile has been found to contain various bioactive compounds, such as alkaloids, bibenzyl, phenanthrene, phenylpropanoids, and polysaccharides. Its medicinal applications are closely correlated to its diverse pharmacological activities, including antitumor, anti-inflammatory, nervous system protective, antifatigue, hypoglycemic, and hypolipidemic actions. In this review, we provide a comprehensive summary of the main chemical constituents and pharmacological activities of D. nobile, as well as the underlying molecular mechanisms for its bioactivities. It is expected that this review will provide a helpful scientific reference for the development and use of D. nobile.

不同施肥处理对金钗石斛光合特性的影响

以贵州省赤水市金钗石斛(Dendrobium nobile Lindl)苗为试验材料,通过不同施肥处理进行单因素分析和正交试验,采用Li-6400型便携式光合作用测量系统(Li-Cor,USA),对金钗石斛光合特性的有关参数进行测试。结果表明,施用Hoaglan营养液能有效改善金钗石斛的净光合速率,光合速率的快慢与金钗石斛气孔导度呈正相关,气孔导度日变化与蒸腾速率日变化有直接关系,所有因子中钾肥对净光合速率、蒸腾速率影响较大,均达显著水平,而影响气孔导度的是氮肥,生产中应合理施用钾肥、氮肥。