Opposite trends of glycosides and alkaloids in Dendrobium nobile of different age based on UPLC-Q/TOF-MS combined with multivariate statistical analyses.

INTRODUCTION: Alkaloids and glycosides are the active ingredients of the herb Dendrobium nobile, which is used in traditional Chinese medicine. The pharmacological effects of alkaloids include neuroprotective effects and regulatory effects on glucose and lipid metabolism, while glycosides improve the immune system. The pharmacological activities of the above chemical components are significantly different. In practice, the stems of 3-year-old D. nobile are usually used as the main source of Dendrobii Caulis. However, it has not been reported whether this harvesting time is appropriate. OBJECTIVE: The aim of this study was to compare the chemical characteristics of D. nobile in different growth years (1-3 years). METHODS: In this study, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF-MS) was employed to analyze the constituents of D. nobile. The relative abundance of each constituent was analyzed with multivariate statistical analyses to screen the characteristic constituents that contributed to the characterization and classification of D. nobile. Dendrobine, a component of D. nobile that is used for quality control according to the Chinese Pharmacopoeia, was assayed by gas chromatography. RESULTS: As a result, 34 characteristic constituents (VIP > 2) were identified or tentatively identified as alkaloids and glycosides based on MS/MS data. Moreover, the content of alkaloids decreased over time, whereas the content of glycosides showed the opposite trend. The absolute quantification of dendrobine was consistent with the metabolomics results. CONCLUSION: Our findings provide valuable information to optimize the harvest period and a reference for the clinical application of D. nobile.

Zuotai (ß-HgS)-containing 70 Wei Zhen-Zhu-Wan differs from mercury chloride and methylmercury on hepatic cytochrome P450 in mice.

Background: Zuotai (mainly ß-HgS)-containing 70 Wei-Zhen-Zhu-Wan (70W, Rannasangpei) is a famous Tibetan medicine for treating cardiovascular and gastrointestinal diseases.  We have shown that 70W protected against CCl 4 hepatotoxicity.  CCl 4 is metabolized via cytochrome P450 (CYP) to produce reactive metabolites. Whether 70W has any effect on CYPs is unknown and such effects should be compared with mercury compounds for safety evaluation.   Methods: Mice were given clinical doses of 70W (0.15-1.5 g/kg, po), Zuotai (30 mg/kg, po), and compared to HgCl 2 (33.6 mg/kg, po) and MeHg (3.1 mg/kg, po) for seven days. Liver RNA and protein were isolated for qPCR and Western-blot analysis. Results: 70W and Zuotai had no effects on hepatic mRNA expression of Cyp1a2, Cyp2b10, Cyp3a11, Cyp4a10 and Cyp7a1, and corresponding nuclear receptors [aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor-α (PPARα); farnesoid X receptor (FXR)]. In comparison, HgCl 2 and MeHg increased mRNA expression of Cyp1a2, Cyp2b10, Cyp4a10 and Cyp7a1 except for Cyp3a11, and corresponding nuclear receptors except for PXR. Western-blot confirmed mRNA results, showing increases in CYP1A2, CYP2B1, CYP2E1, CYP4A and CYP7A1 by HgCl 2 and MeHg only, and all treatments had no effects on CYP3A. Conclusions: Zuotai and Zuotai-containing 70W at clinical doses had minimal influence on hepatic CYPs and corresponding nuclear receptors, while HgCl 2 and MeHg produced significant effects.  Thus, the use of total Hg content to evaluate the safety of HgS-containing 70W is inappropriate.

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 (Aß)-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 Aß25-35 (10 µM). Aß25-35 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 Aß25-35 on these cellular properties was markedly attenuated when cells were pretreated with DNLA. Treatment with Aß25-35 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 Aß25-35 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.

Dendrobium alkaloids prevent Aß25-35-induced neuronal and synaptic loss via promoting neurotrophic factors expression in mice.

BACKGROUND: Neuronal and synaptic loss is the most important risk factor for cognitive impairment. Inhibiting neuronal apoptosis and preventing synaptic loss are promising therapeutic approaches for Alzheimer's disease (AD). In this study, we investigate the protective effects of Dendrobium alkaloids (DNLA), a Chinese medicinal herb extract, on ß-amyloid peptide segment 25-35 (Aß25-35)-induced neuron and synaptic loss in mice. METHOD: Aß25-35(10 µg) was injected into the bilateral ventricles of male mice followed by an oral administration of DNLA (40 mg/kg) for 19 days. The Morris water maze was used for evaluating the ability of spatial learning and memory function of mice. The morphological changes were examined via H&E staining and Nissl staining. TUNEL staining was used to check the neuronal apoptosis. The ultrastructure changes of neurons were observed under electron microscope. Western blot was used to evaluate the protein expression levels of ciliary neurotrophic factor (CNTF), glial cell line-derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF) in the hippocampus and cortex. RESULTS: DNLA significantly attenuated Aß25-35-induced spatial learning and memory impairments in mice. DNLA prevented Aß25-35-induced neuronal loss in the hippocampus and cortex, increased the number of Nissl bodies, improved the ultrastructural injury of neurons and increased the number of synapses in neurons. Furthermore, DNLA increased the protein expression of neurotrophic factors BDNF, CNTF and GDNF in the hippocampus and cortex. CONCLUSIONS: DNLA can prevent neuronal apoptosis and synaptic loss. This effect is mediated at least in part via increasing the expression of BDNF, GDNF and CNTF in the hippocampus and cortex; improving Aß-induced spatial learning and memory impairment in mice.