A rapid capillary zone electrophoresis (CZE) method with ephedrine hydrochloride as an internal standard was developed and validated for separating and quantifying the alkaloids strychnine (1), brucine (2), strychnine N-oxide (3), and brucine N-oxide (4) in the seed of Strychnos nux-vomica L. (crude nux vomica) and its fermented products by fungus Trametes cinnabarina (Jacq.: Fr.) Fr. (fermented nux vomica). The contents of alkaloids (1 and 2) in crude nux vomica were higher than those in fermented drugs, whereas alkaloids (3 and 4) were only detected in fermented ones. The method developed is sensitive, specific and accurate, as well as effective and easy, which can be used to assess the qualities of crude and fermented nux vomica.Keywords Capillary zone electrophoresis Á Strychnine and strychnine N-oxide Á Brucine and brucine N-oxide Á Ephedrine hydrochloride Á Crude and fermented nux vomica
The accumulation of β-amyloid (Aβ) in the brain plays an important role in the pathogenesis of Alzheimer’s disease (AD). The lack of estrogen is one of the risk factors for AD. Quercetin is a phytoestrogen with a chemical structure similar to that of estrogen. However, the mechanism by which quercetin prevents AD is unclear. PC12 cells were cultured with Aβ25–35 for 24 h. Then the cells were further treated with 17β-estradiol, genistein, and quercetin for another 24 h, respectively. Next, ICI182780 and U0126 were used to study the mechanisms of estrogen-like neuroprotection. Methyl thiazolyl tetrazolium (MTT) assay was performed to detect cell survival. The protein expression was analyzed by immunofluorescence and western blot. The survival of PC12 cells induced by Aβ25–35 was increased by quercetin. The levels of estrogen receptor α (ERα) and p-extracellular signal-regulated kinase (ERK)1/2 were improved by quercetin, but not those of ERβ. On the contrary, Bcl-2/Bax was increased and the expression of Caspase-3 was decreased. When the cell was pretreated with ICI182780, the p-ERK1/2 and Bcl-2/Bax ratio was decreased, but Caspase-3 expression was increased. In addition, pretreatment with U0126 would reduce Bcl-2/Bax ratio and increase Caspase-3 protein expression. Conclusively, quercetin plays a neuroprotective role through the ER pathway and the mitogen-activated protein kinase (MAPK) pathway. The MAPK signaling pathways could also be activated by quercetin via the mediation of ERα.
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