Dendrobium alkaloids prevent Aβ25-35-induced neuronal and synaptic loss via promoting neurotrophic factors expression in mice

Dendrobium nobile Lindl ameliorates learning and memory deficits in scopolamine-treated mice

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium nobile Lindl (DNL), a valued time-honored herb, possesses immune-boosting and age-delaying properties, has been widely used to treat hyperglycemia and neurological diseases, and is probably a potential drug for improving learning and memory. Scopolamine (Scop), an antagonist for muscarinic receptors, potentially impairing intelligence and memory.

AIM OF THE STUDY

This investigation aimed to assess the efficacy of DNL in alleviating scopolamine-induced cognitive deficits in mice and its mechanisms.

MATERIALS AND METHODS

We utilized the open-field test, novel object recognition test (NOR), and Morris water maze test (MWM) to assess the potential of DNL in ameliorating learning and memory dysfunction caused by scopolamine in mice. Enzyme-linked immunosorbent assay (ELISA) was employed to measure Choline acetyltransferase (ChAT) content and Acetylcholinesterase (AChE) activities in the brain, and oxidative stress-related factors in the serum, including Malondialdehyde (MDA), Superoxide dismutase (SOD), and glutathione (GSH) content.

RESULTS

Scopolamine injection significantly reduced the discrimination index of mice in the NOR test and impaired their performance in the MWM test, as demonstrated by longer escape latency, fewer target crossings, and less time spent in the target quadrant in the MWM. After 25 days of administration, DNL increased the discrimination index of the scopolamine-treated mice in the NOR test. DNL reduced the escape latency in the MWM test in the model mice. DNL increased the target crossing number and the percentage of time spent in the target quadrant in the MWM test. ELISA experiments indicated that DNL decreased the AChE activities, increased the ChAT activities, and modulated oxidative stress makers (GSH, SOD, and MDA) in scopolamine-induced mice.

CONCLUSIONS

DNL may improve the learning and memory in mice treated with scopolamine, possibly by modulating oxidative stress and impaired cholinergic function.

Dendrobium nobile Lindl. alkaloid decreases Tau hyperphosphorylation via regulating PI3K/Akt/GSK-3β pathway in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANT

Dendrobium is a traditional and precious Chinese medicinal herb. The Compendium of Materia Medica describes its effects as "benefiting intelligence and dispelling shock, lightning the body and extending life". Dendrobium nobile Lindl. is a precious variety of Dendrobium. Our previous data showed Dendrobium nobile Lindl. alkaloid (DNLA) has significant neuroprotective effects and can improve cognitive dysfunction. However, the specific effects and mechanisms of action of its main active component, DNLA, on cognitive dysfunction caused by Tau hyperphosphorylation, are still unclear.

AIM OF THE RESEARCH

This study aimed to determine the effects of DNLA on phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase 3β (GSK-3β) pathway, thus to explore the mechanisms of DNLA to inhibit Tau hyperphosphorylation.

MATERIALS AND METHODS

We used wortmannin (WM) and GF-109203X (GFX)-induced hyperphosphorylation of Tau in N2a cells and rats to detect the protective mechanism of DNLA in vivo and in vitro. In vitro, the effect of modeling method on Tau hyperphosphorylation was screened and verified by Western Blotting (WB), and the regulation of Tau hyperphosphorylation and PI3K/Akt/GSK-3β pathway by different concentrations of DNLA was detected by WB. In vivo, MWM was used to detect the effect of DNLA on model rats, and then Nissl staining was used to detect the loss of neurons. Finally, WB was used to detect the regulation of Tau hyperphosphorylation and PI3K/Akt/GSK-3β pathway by different concentrations of DNLA.

RESULTS

DNLA could rescue the abnormal PI3K/Akt/GSK-3β pathway and reverse the hyperphosphorylation of Tau induced by WM and GFX in N2a cells. Furthermore, DNLA improved the learning and memory of WM and GFX-induced model rats. Moreover, DNLA regulated PI3K/Akt/GSK-3β pathway and reduced the p-Tau and neuronal damage in the hippocampus of model rats.

CONCLUSION

DNLA may be a promising candidate for reducing hyperphosphorylation of Tau.

Phytochemical Profile of Alkaloid Extract from Dendrobium huoshanense and Inhibitory Effects against Oxidative Stress in H2 O2 -Induced PC12 Cells

This study aimed to explore the alkaloid profile of Dendrobium huoshanense and determine the potential protective effect against oxidative damage. The crude D. huoshanense alkaloid extract (DHAE) was obtained by 70 % ethanol extraction and liquid-liquid partition. DHAE contained specific alkaloid components with abundant 6-hydroxynobiline (58.15 %) and trace dendrobine (3.23 %) in the preliminary HPLC fingerprint and GC-MS analysis, which was distinguished from D. officinale or D. nobile. Subsequently, six alkaloids including 6-hydroxynobiline, 2-hydroxy dendrobine, nobilonine, dendrobine, Findlayines D and trans-dendrochrysanine were identified in the purified DHAE (namely DHSAE-3, DHSAE-3') via further solid phase extraction coupled with UPLC-MS/MS analysis. Meanwhile, pretreatment with DHAE or DHSAE (0.5, 5 μg/mL) increased cell viability by 14.0-57.4 % compared to that of H2 O2 -induced PC12 Model cells. Among them, 5 μg/mL DHSAE-3-treated cells displayed a pronounced reversion than the positive vitamin E (p<0.01). Furthermore, a clear cellular morphological restoration and 38.4 % reduction in intracellular reactive oxidative species level were achieved. Our findings suggest that D. huoshanense has a characteristic alkaloid profile represented by abundant 6-hydroxynobiline, and DHAEs exhibit obvious protection against oxidative neuronal damage. Overall, this study indicates that DHAEs might be used to inhibit oxidative stress and provide a source to develop novel neuroprotective drugs.

Discovery of a 4-Hydroxy-3'-Trifluoromethoxy-Substituted Resveratrol Derivative as an Anti-Aging Agent

With the intensification of population aging, aging-related diseases are attracting more and more attention, thus, the study of aging mechanisms and anti-aging drugs is becoming increasingly urgent. Resveratrol is a potential candidate as an anti-aging agent, but its low bioavailability limits its application in vivo. In this work, a 4-hydroxy-3'-trifluoromethoxy-substituted resveratrol derivative (4-6), owing to its superior cell accumulation, could inhibit NO production in an inflammatory cell model, inhibit oxidative cytotoxicity, and reduce ROS accumulation and the population of apoptotic cells in an oxidative stress cell model. In D-galactose (D-gal)-stimulated aging mice, 4-6 could reverse liver and kidney damage; protect the serum, brain, and liver against oxidative stress; and increase the body's immunity in the spleen. Further D-gal-induced brain aging studies showed that 4-6 could improve the pathological changes in the hippocampus and the dysfunction of the cholinergic system. Moreover, protein expression related to aging, oxidative stress, and apoptosis in the brain tissue homogenate measured via Western blotting also showed that 4-6 could ameliorate brain aging by protecting against oxidative stress and reducing apoptosis. This work revealed that meta-trifluoromethoxy substituted 4-6 deserved to be further investigated as an effective anti-aging candidate drug.

Research progress of plant-derived natural alkaloids in central nervous system diseases

Central nervous system (CNS) disease is one of the most important causes of human death. Because of their complex pathogenesis, more and more attention has been paid to them. At present, drug treatment of the CNS is the main means; however, most drugs only relieve symptoms, and some have certain toxicity and side effects. Natural compounds derived from plants can provide safer and more effective alternatives. Alkaloids are common nitrogenous basic organic compounds found in nature, which exist widely in many kinds of plants and have unique application value in modern medicine. For example, Galantamine and Huperzine A from medicinal plants are widely used drugs on the market to treat Alzheimer's disease. Therefore, the main purpose of this review is to provide the available information on natural alkaloids with the activity of treating central nervous system diseases in order to explore the trends and perspectives for the further study of central nervous system drugs. In this paper, 120 alkaloids with the potential effect of treating central nervous system diseases are summarized from the aspects of sources, structure types, mechanism of action and structure-activity relationship.

Plasma long non-coding RNAs ASMTL-AS1, AP001363.1, AC005730.3 and AL133415.1 as a potential biomarker for Alzheimer's disease

BACKGROUND

Long non-coding RNAs (lncRNAs) play critical role in the pathogenesis of neurodegenerative diseases. Human plasma contains lncRNAs that are present in the blood, and their disease-specific profile has been considered a potential biomarker in some diseases.

METHODS

This study reports screening of the plasma levels of lncRNAs between Alzheimer disease(AD) (n = 45) and matched healthy controls (n = 45). The plasma samples of 5 AD patients and 5 matched healthy controls were randomly selected for expression levels of lncRNAs using the TruSeq RNA Sample Prep Kit (Illumina). The receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to study the potential of lncRNAs as biomarkers.

RESULTS

The differential expression profiles of plasma showed that 514 lncRNAs were upregulated, whereas 499 lncRNAs were downregulated.We found that the lncRNAs AL133415.1, AC020916.1, ENST00000654948, ASMTL-AS, AC005730.3, and AP001363.1 levels in the plasma of the AD patients were significantly lower compared to the control group (p1 = 0.0006, p2 < 0.001, p3 < 0.001, p4 = 0.039, p5 = 0.006, p6 < 0.001, respectively). ROC curve analysis revealed that the AUC of AL133415.1 was 0.635 (95% CI]: 0.507-0.763, p = 0.036), the AUC of ASMTL-AS1 was 0.658 (95% CI: 0.513-0.785, p = 0.015), the AUC of AC005730.3 was 0.627 (95%CI: 0.498-0.756, p = 0.049), and the AUC of AP001363.1 was 0.708 (95%CI: 0.595-0.822, p = 0.001).

CONCLUSION

This study indicated that the plasma levels of the lncRNAs ASMTL-AS1, AP001363.1, AC005730.3, and AL133415.1 might be considered potential biomarkers for AD in the Chinese Population.

Proteomic analysis of anti-aging effects of Dendrobium nobile Lindl. alkaloids in aging-accelerated SAMP8 mice

Senescence-accelerated mouse prone 8 (SAMP8) mice exhibit cognitive defects and neuron loss with aging, and were used to study anti-aging effects of Dendrobium nobile alkaloids (DNLA). DNLA (20 and 40 mg/kg) were orally administered to SAMP8 mice from 6 to 10 months of age. At 10-month of age, behavioral tests via Y-maze and Open-field and neuron damage via Nissl staining were evaluated. Protein was extracted and subjected to phosphorylated proteomic analysis followed by bioinformatic analysis. The cognitive deficits and neuron loss in hippocampus and cortex of aged SAMP8 mice were improved by DNLA. Hippocampal proteomic analysis revealed 196 differentially expressed protein/genes in SAMP8 compared to age-matched senescence-accelerated resistant SAMR1 mice. Gene Oncology enriched the tubulin binding, microtubule binding, and other activities. Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed endocytosis, mRNA surveillance, tight junction, protein processing in endoplasmic reticulum, aldosterone synthesis and secretion, and glucagon signaling pathway changes. Upregulated protein/genes in the hippocampus of SAMP8 mice, such as Lmtk3, Usp10, Dzip1, Csnk2b, and Rtn1, were attenuated by DNLA; whereas downregulated protein/genes, such as Kctd16, Psd3, Bsn, Atxn2l, and Kif1a, were rescued by DNLA. The aberrant protein/gene expressions of SAMP8 mice were correlated with transcriptome changes of Alzheimer's disease in the Gene Expression Omnibus (GEO) database, and the scores were attenuated by DNLA. Thus, DNLA improved cognitive dysfunction and ameliorated neuronal injury in aged SAMP8 mice, and attenuated aberrant protein/gene expressions.

Natural bioactive compounds in Alzheimer's disease: From the perspective of type 3 diabetes mellitus

There is a close relationship between Alzheimer's disease (AD) and diabetes mellitus (DM), and the link between the two is often referred to as type 3 diabetes mellitus (T3DM). Many natural bioactive compounds have shown the potential to treat AD and diabetes. We mainly review the polyphenols represented by resveratrol (RES) and proanthocyanidins (PCs) and alkaloids represented by berberine (BBR) and Dendrobium nobile Lindl. alkaloids (DNLA) from the perspective of T3DM to review the neuroprotective effects and molecular mechanisms of natural compounds in AD.

Nanocarriers for the Delivery of Neuroprotective Agents in the Treatment of Ocular Neurodegenerative Diseases

Retinal neurodegeneration is considered an early event in the pathogenesis of several ocular diseases, such as diabetic retinopathy, age-related macular degeneration, and glaucoma. At present, there is no definitive treatment to prevent the progression or reversal of vision loss caused by photoreceptor degeneration and the death of retinal ganglion cells. Neuroprotective approaches are being developed to increase the life expectancy of neurons by maintaining their shape/function and thus prevent the loss of vision and blindness. A successful neuroprotective approach could prolong patients' vision functioning and quality of life. Conventional pharmaceutical technologies have been investigated for delivering ocular medications; however, the distinctive structural characteristics of the eye and the physiological ocular barriers restrict the efficient delivery of drugs. Recent developments in bio-adhesive in situ gelling systems and nanotechnology-based targeted/sustained drug delivery systems are receiving a lot of attention. This review summarizes the putative mechanism, pharmacokinetics, and mode of administration of neuroprotective drugs used to treat ocular disorders. Additionally, this review focuses on cutting-edge nanocarriers that demonstrated promising results in treating ocular neurodegenerative diseases.

The pathomimetic oAβ25–35 model of Alzheimer's disease: Potential for screening of new therapeutic agents

Alzheimer's disease (AD) is the most common form of dementia in the elderly, currently affecting more than 40 million people worldwide. The two main histopathological hallmarks of AD were identified in the 1980s: senile plaques (composed of aggregated amyloid-β (Aβ) peptides) and neurofibrillary tangles (composed of hyperphosphorylated tau protein). In the human brain, both Aβ and tau show aggregation into soluble and insoluble oligomers. Soluble oligomers of Aβ include their most predominant forms - Aβ_1-40 and Aβ_1-42 - as well as shorter peptides such as Aβ_25-35 or Aβ_25-35/40. Most animal models of AD have been developed using transgenesis, based on identified human mutations. However, these familial forms of AD represent less than 1% of AD cases. In this context, the idea emerged in the 1990s to directly inject the Aβ_25-35 fragment into the rodent brain to develop an acute model of AD that could mimic the disease's sporadic forms (99% of all cases). This review aims to: (1) summarize the biological activity of Aβ_25-35, focusing on its impact on the main structural and functional alterations observed in AD (cognitive deficits, APP misprocessing, tau system dysfunction, neuroinflammation, oxidative stress, cholinergic and glutamatergic alterations, HPA axis dysregulation, synaptic deficits and cell death); and (2) confirm the interest of this pathomimetic model in AD research, as it has helped identify and characterize many molecules (marketed, in clinical development, and in preclinical testing), and to the development of alternative approaches for AD prevention and therapy. Today, the Aβ_25-35 model appears as a first-intent choice model to rapidly screen the symptomatic or neuroprotective potencies of new compounds, chemical series, or innovative therapeutic strategies.

Anti-depressant-like effect of fermented Gastrodia elata Bl. by regulating monoamine levels and BDNF/NMDAR pathways in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Gastrodia elata Blume (GE) is a Chinese medicinal herb commonly used to treat central nervous system-related diseases, including headaches, dizziness, epilepsy, numbness of the limbs and depression.

AIM OF THE STUDY

Microbial-based fermentation has been successfully used to increase the extract efficiency of medicinal herbs in recent years. However, no study has hitherto explored the anti-depressant-like effect of GE processed by microorganisms. Herein, this subject aimed to clarify the anti-depressant-like effect of fermented Gastrodia elata Bl. (FGE) and its active chemical constituents.

MATERIALS AND METHODS

The chronic unpredictable mild stress (CUMS) model, a well-established animal model of depression, was induced in Kunming (KM) mice. The mice were administrated with FGE for 3 weeks. The sucrose preference test (SPT), open field test (OFT) and tail suspension test (TST) were conducted. Moreover, the levels of serotonin (5-HT) and dopamine (DA) in brain tissue homogenates, the concentration of Ca²⁺ and the activity of MAO in serum, H&E and Nissl staining in the hippocampus, and the hippocampus protein expressions of BDNF, NMDAR1, NMDAR2A and NMDAR2B relevant to depression were detected. Furthermore, chemical constituents of FGE were further isolated, and the protective activity of the obtained compounds against NMDA-induced PC-12 cell damage was assessed.

RESULTS

FGE could alleviate the depression state in CUMS-induced mice and reduce apoptosis of neuronal cells in the hippocampus. Furthermore, FGE could improve the contents of 5-HT, DA and decrease the concentration of Ca²⁺ and MAO activity in brain tissue and serum compared with the control group. It could reverse the decreased expression of BDNF, NMDAR2A and NMDAR2B and increase NMDAR1 protein expression. Investigation of the active constituents from FGE yielded two new compounds, (4-(((4-ethoxybenzyl) oxy)methyl)-phenol 1 and 3-((4-hydroxy benzyl)oxy)propane-1,2-diol) 2, with twelve known compounds (3-14). The compounds (3-((4-hydroxybenzyl)oxy)propane-1,2-diol 2, 4, 4'-dihydroxyd iphenyl methane 3, and bungein A 4) protected against NMDA-induced PC-12 cells damage.

CONCLUSION

This study demonstrated that FGE could improve the depressive behavior of CUMS-induced mice and exert a protective effect on nerve cells in the brain. Importantly, compounds 2-4 are the active components of FGE. Overall, the above findings suggest that FGE has huge prospects for application in treating depression-related diseases.

Dendrobine Alleviates Cellular Senescence and Osteoarthritis via the ROS/NF-κB Axis

Osteoarthritis (OA) is a degenerative joint disease characterized by low-grade inflammation and cartilage degradation. Dendrobine (DEN) is reported to inhibit inflammation and oxidative stress in some diseases, but its role in chondrocyte senescence and OA progress has not yet been elucidated. Our study aimed to explore the protective effects of DEN on OA both in vitro and in vivo. We found that DEN inhibited extracellular matrix (ECM) degradation and promoted ECM synthesis. Meanwhile, DEN inhibited senescence-associated secretory phenotype (SASP) factors expression and senescence phenotype in IL-1β-treated chondrocytes. Furthermore, DEN improved mitochondrial function and reduced the production of intracellular reactive oxygen species (ROS). Also, DEN suppressed IL-1β-induced activation of the NF-κB pathway. Further, using NAC (ROS inhibitor), we found that DEN might inhibit NF-κB cascades by reducing ROS. Additionally, X-ray, micro-CT, and histological analyses in vivo demonstrated that DEN significantly alleviated cartilage inflammation, ECM degradation, and subchondral alterations in OA progression. In conclusion, DEN inhibits SASP factors expression and senescence phenotype in chondrocytes and alleviated the progression of OA via the ROS/NF-κB axis, which provides innovative strategies for the treatment of OA.

Research progress in traditional Chinese medicine in the treatment of Alzheimer's disease and related dementias

Alzheimer's disease (AD) is the world's leading cause of dementia and has become a huge economic burden on nations and families. However, the exact etiology of AD is still unknown, and there are no efficient medicines or methods to prevent the deterioration of cognition. Traditional Chinese medicine (TCM) has made important contributions in the battle against AD based on the characteristics of multiple targets of TCM. This study reviewed the treatment strategies and new discoveries of traditional Chinese medicine in current research, which may be beneficial to new drug researchers.

Transcriptome Analysis of Protection by Dendrobium Nobile Alkaloids (DNLA) against Chronic Alcoholic Liver Injury in Mice

Objective: To investigate the protective effects of Dendrobium nobile Lindl. alkaloids (DNLA) against chronic alcoholic liver injury. C57BL/6J mice were fed with the Lieber−DeCarli alcohol diet to induce chronic alcoholic liver injury. DNLA (20 mg/kg/day) was gavaged along with the alcohol diet for 28 days. Liver injury was evaluated by serum enzymes. Triglyceride levels, histopathology, and transcriptome changes were examined by RNA-Seq and qPCR. DNLA decreased serum triglyceride levels in mice receiving alcohol. Hepatocyte degeneration and steatosis were ameliorated by DNLA, as evidenced by H&E and Oil-red O staining. DNLA brought the alcohol-induced aberrant gene expression pattern towards normal. Alcohol induced 787 differentially expressed genes (padj < 0.01). DNLA induced 280 differentially expressed genes to a much less extent. Ingenuity pathway analysis showed that DNLA ameliorated alcohol-induced oxidative stress and xenobiotic metabolism disruption. qPCR verified that DNLA alleviated over-activation of Cyp2a4, Cyp2b10, and Abcc4; attenuated oxidative stress (Hmox1, Gstm3, Nupr1), reduced the expression of Nrf2 genes (Nqo1, Gclc, Vldlr); and rescued some metabolic genes (Insig1, Xbp1, Socs3, Slc10a2). In conclusion, DNLA was effective against alcohol-induced fatty liver disease, and the protection may be attributed to alleviated oxidative stress and restored metabolism homeostasis, probably through modulating nuclear receptor CAR-, PXR-, and Nrf2-mediated gene expression pathways.

Alkaloids from Dendrobium and their biosynthetic pathway, biological activity and total synthesis

BACKGROUND

Dendrobium Sw. has been used for thousands of years in China as a precious traditional Chinese medicine. It is derived from stems of various Dendrobium plants and has the functions of nourishing Yin and clearing heat, activating water and nourishing the stomach, moistening the lung and relieving cough. Modern phytochemical studies show that the main components of Dendrobium include alkaloids, polysaccharides, terpenoids, diphenylbenzene, and phenanthrene. Alkaloids are natural products with obvious biological activity and are important effective components of the medicinal activity or toxicity of plants. At present, dozens of alkaloids with various structures have been isolated from Dendrobium plants, and the alkaloid contents in Dendrobium plants of different species are quite different. From the perspective of food safety, the type, molecular structure, content and potential physiological activity or toxicity of alkaloids are important bases for evaluating the safety of edible plants. Studies have shown that the alkaloids isolated from Dendrobium have neuroprotective, anti-inflammatory and antitumor activities, showing that these alkaloids with potential medicinal activity are important sources of lead compounds in innovative drug development.

PURPOSE

To summarize the research progress on alkaloids in Dendrobium and provide a reference for research on the food safety and medicinal development of Dendrobium.

METHOD

Information about alkaloids from Dendrobium was collected from the scientific databases Web of Science, PubChem and PubMed. We discuss the biosynthetic pathway, biological activities and total synthesis of alkaloids from Dendrobium from 1964 to 2020 and summarize the knowledge of alkaloids from Dendrobium, the biosynthetic pathway, biological activities and total synthesis. We chose publications on their chemistry, drug effects, pharmacology, metabolism and biosynthesis, physiology and toxicity. Alkaloids, Dendrobium, biosynthetic pathway and biological activities were used as keywords to extract the relevant literature.

CONCLUSION

In this paper, the structural classification, biological activity, target and toxicology and synthesis of the alkaloids in Dendrobium were systematically reviewed, which will provide a reference for the safety, development and application of Dendrobium.

Identification of Dendrobiums in situ by Raman spectroscopy and micro-computed tomography imaging

Background

Dendrobium candidum/officinale (Dendrobium candidum Wall.ex Lindl.; Dendrobium officinale Kimura et Migo) is an expensive medicinal plant used mainly as a tonic in China. Tie-pi-feng-dou is the common name of the processed medicinal Dendrobium candidum/officinale. The market prices of Dendrobium sources vary significantly and it is difficult to identify different types of Dendrobiums due to their similar appearances. The use of counterfeit Dendrobium candidum/officinale is ubiquitous and problematic. Therefore, it is important to be able to discriminate between the wide range of available Dendrobium.

Methods

In an effort to better distinguish between the varieties of Dendrobium, Raman spectroscopy was used to detect specific Dendrobiums relative to their source. Transport channel imaging of the microstructural sites by micro-computed tomography (micro-CT) was used to identify the unique constitution and enrichment status of dendrobines, which was determined mainly by the geographical source of the Dendrobium. This implies that exclusive spectral traits may be unique to different regions. The presence or absence of these traits differ among the geographical origins.

Results

We can identify several spectral traits for various Dendrobiums. An intense peak at 1,525 cm−1 was only found in Dendrobium candidum/officinale (Zhe-jiang/Yun-nan/An-hui), while the characteristic Dendrobium candidum/officinale bands were near 742 cm−1, 1,326 cm−1 and 1,330 cm−1. A systematic method for distinguishing between four geographical locations of Dendrobium (Zhe-jiang/Yun-nan/An-hui/Gui-zhou) were established. This reveals that the origin of an unknown Dendrobium may be identified by Raman spectroscopy and micro-CT imaging. This method was shown to be efficacious, fast, and non-destructive.

Dendrobium Nobile Lindl. Alkaloid Suppresses NLRP3-Mediated Pyroptosis to Alleviate LPS-Induced Neurotoxicity

Alzheimer’s disease (AD) is a neurodegenerative disorder recognized as a global public health priority. Although available treatments temporarily relieve the symptoms, they could not prevent the progression of cognitive decline. Natural compounds have been rich sources for drug discovery. Dendrobium nobile Lindl. alkaloid (DNLA) is the main active compound in Dendrobium nobile Lindl, a traditional Chinese herbal medicine. Recent studies indicated that DNLA produced neuroprotection. However, the mechanisms underlying DNLA-generated neuroprotection remain unknown. To investigate neuroprotection and the underlying mechanisms of DNLA, mouse hippocampus injection of lipopolysaccharide (LPS)-induced neuronal damage was performed. DNLA protected hippocampus neurons and working memory disorder against LPS-induced neurotoxicity. In addition, DNLA suppressed cell undergoing membrane lysis and cell swelling and inhibited the essential mediator of pyroptosis GSDMD-N expressions. Furthermore, DNLA-mediated neuroprotection was dependent on the inhibition of NLRP3 inflammasome activation, as evidenced by the fact that DNLA reduced pro-inflammatory factor (IL-18 and IL-1β) production and inhibited the expression of related proteins. DNLA-exerted neuroprotection against LPS-induced neuronal damage, and cognitive impairment was not observed in NLRP3 knockout mice. Together, this study suggested that DNLA attenuated NLRP3-mediated pyroptosis to generate neuroprotection against LPS-induced neuronal damage and cognitive impairment.

Potential neuroprotection by Dendrobium nobile Lindl alkaloid in Alzheimer's disease models

At present, treatments for Alzheimer's disease can temporarily relieve symptoms but cannot prevent the decline of cognitive ability and other neurodegenerative changes. Dendrobium nobile Lindl alkaloid is the main active component of Dendrobium nobile Lindl. Dendrobium nobile Lindl alkaloid has been shown to resist aging, prolong life span, and exhibit immunomodulatory effects in animals. This review summarizes the mechanisms behind the neuroprotective effects reported in Alzheimer's disease animal models. The neuroprotective effects of Dendrobium nobile Lindl alkaloid have not been studied in patients. The mechanisms by which Dendrobium nobile Lindl alkaloid has been reported to improve cognitive dysfunction in Alzheimer's disease animal models may be associated with extracellular amyloid plaque production, regulation of tau protein hyperphosphorylation, inhibition of neuroinflammation and neuronal apoptosis, activation of autophagy, and enhanced synaptic connections.

Dendrobium nobile protects retinal cells from UV-induced oxidative stress damage via Nrf2/HO-1 and MAPK pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Excessive UV irradiation and ROS exposure are the main contributors of ocular pathologies. Pseudobulb of Dendrobium nobile Lindl. is one of the sources of Shihu and has long been used in traditional Chinese medicine as a tonic to nourish stomach, replenish body fluid, antipyretic and anti-inflammation.

AIM OF STUDY

This study aimed to investigate whether D. nobile could protect ocular cells against oxidative stress damage.

MATERIALS AND METHODS

Retinal-related cell lines, ARPE-19 and RGC-5 cells, were pretreated with D. nobile extracts before H₂O₂- and UV-treatment. Cell viability and the oxidative stress were monitored by sulforhodamine B (SRB) and SOD1 and CAT assay kits, respectively. The oxidative stress related proteins were measured by Western blotting.

RESULTS

Under activity-guided fractionation, a sesquiterpene-enriched fraction (DN-2) and a major component (1) could ameliorate H₂O₂- and UV-induced cytotoxicity and SOD1 and CAT activity, but not dendrobine, the chemical marker of D. nobile. Western blotting showed both DN-2 and compound 1 protected ARPE-19 cells against UV-induced oxidative stress damage by regulating MAPK and Nrf2/HO-1 signaling.

CONCLUSION

Our results suggest D. nobile extract protects retinal pigment epithelia cells from UV- and oxidative stress-damage, which may have a beneficial effect on eye diseases.

Protective Effects of Dendrobium nobile Lindl. Alkaloids on Alzheimer's Disease-like Symptoms Induced by High-methionine Diet

BACKGROUND

High methionine-diet (HMD) causes Alzheimer's disease (AD)-like symptoms. Previous studies have shown that Dendrobium nobile Lindle. alkaloids (DNLA) have potential benefits for AD Object: The objective of this study has been to explore whether DNLA can improve AD-like symptoms induced by HMD.

METHODS

Mice were fed with 2% HMD diet for 11 weeks; the DNLA20 control group (20 mg/kg), DNLA10 group (10 mg/kg), and DNLA20 group (20 mg/kg) were administered DNLA for 3 months. Morris water maze test was used to detect learning and memory ability. Neuron damage was evaluated by HE and Nissl staining. Levels of homocysteine (Hcy), beta-amyloid 1-42 (Aβ_1-42), S-adenosine methionine (SAM) and S-adenosine homocysteine (SAH) were detected by ELISA. Immunofluorescence and western blotting (WB) were used to determine the expression of proteins. CPG island methylation levels were accessed by Methylation-specific PCR (MSP) and MethylTarget methylation detection.

RESULTS

Morris water maze test revealed that DNLA improved learning and memory dysfunction. HE, Nissl, and immunofluorescence staining showed that DNLA alleviated neuron damage and reduced the 5-methylcytosine (5-mC), Aβ_1-40) and Aβ_1-42) levels. DNLA also decreased the levels of Hcy and Aβ_1-42) in the serum, along with decreasing SAM/SAH level in the liver tissue. WB results showed that DNLA down-regulated the expression of amyloid-precursor protein (APP), presenilin-1 (PS1), beta-secretase-1 (BACE1), DNA methyltransferase1 (DNMT1), Aβ_1-40) and Aβ_1-42) proteins. DNLA also up-regulated the proteins expression of insulin-degrading enzyme (IDE), neprilysin (NEP), DNMT3a and DNMT3b. Meanwhile, DNLA increased CPG island methylation levels of APP and BACE1 genes.

CONCLUSION

DNLA alleviated AD-like symptoms induced by HMD via the DNA methylation pathway.

Medicine-Food Herbs against Alzheimer’s Disease: A Review of Their Traditional Functional Features, Substance Basis, Clinical Practices and Mechanisms of Action

Alzheimer’s disease (AD) is a progressive, neurodegenerative disorder that currently has reached epidemic proportions among elderly populations around the world. In China, available traditional Chinese medicines (TCMs) that organically combine functional foods with medicinal values are named “Medicine Food Homology (MFH)”. In this review, we focused on MFH varieties for their traditional functional features, substance bases, clinical uses, and mechanisms of action (MOAs) for AD prevention and treatment. We consider the antiAD active constituents from MFH species, their effects on in vitro/in vivo AD models, and their drug targets and signal pathways by summing up the literature via a systematic electronic search (SciFinder, PubMed, and Web of Science). In this paper, several MFH plant sources are discussed in detail from in vitro/in vivo models and methods, to MOAs. We found that most of the MFH varieties exert neuroprotective effects and ameliorate cognitive impairments by inhibiting neuropathological signs (Aβ-induced toxicity, amyloid precursor protein, and phosphorylated Tau immunoreactivity), including anti-inflammation, antioxidative stress, antiautophagy, and antiapoptosis, etc. Indeed, some MFH substances and their related phytochemicals have a broad spectrum of activities, so they are superior to simple single-target drugs in treating chronic diseases. This review can provide significant guidance for people’s healthy lifestyles and drug development for AD prevention and treatment.

Dendrobium nobile Lindl. Alkaloids Ameliorate Aβ25-35-Induced Synaptic Deficits by Targeting Wnt/β-Catenin Pathway in Alzheimer’s Disease Models

Background: Dendrobium nobile Lindl. alkaloids (DNLA) are effective in ameliorating cognitive deficit in SAMP8, AβPP/PS1, and LPS-induced AD animal models, and prevented Aβ-induced synaptic degeneration in cultured hippocampal neurons. However, the underlying mechanisms remain unexplored. Objective: This study investigated the protective effects of DNLA on synaptic damage in an Aβ 25-35-induced rat AD model, in primary cortical neuron cultures, and in PC12 cells transfected with human AβPP695, focusing on the Wnt/β-catenin pathway. Methods: Sprague-Dawley rats received a single Aβ 25-35 injection (10μg) into the bilateral hippocampi. DNLA (40 and 80 mg/kg/d) was intragastrically administrated 7d prior to Aβ injection and continued for 28 days. The spatial learning and memory, synaptic morphology, synapse-related proteins, and Wnt signaling components GSK3β and β-catenin phosphorylation were evaluated. Rat primary cortical neuron cultures and AβPP695-PC12 cells were used to evaluate axonal mitochondria distribution, reactive oxygen species production, amyloidogenesis, and Wnt pathway in the protection. Results: DNLA ameliorated Aβ-induced cognitive impairment, increased the number of synapses, elevated the postsynaptic density thickness and expression of synapsin and PSD95 in the hippocampus, and suppressed Aβ-mediated GSK3β activity and the β-catenin phosphorylation. In primary neurons and AβPP695-PC12 cells, DNLA restored Aβ 25-35 induced mitochondrial dysfunction and inhibited reactive oxygen species production and amyloidogenesis. Furthermore, the Wnt/β-catenin pathway inhibitor Dkk-1 blocked the effect of DNLA on the expression of Aβ 1-42 and PSD95. Conclusion: DNLA rescued Aβ-mediated synaptic and mitochondrial injury and inhibited amyloidogenesis in vivo and in vitro, probably through the activation of Wnt/β-catenin signaling pathway to protect synaptic integrity.

Metabolism of Du Zhong Formula in rats using UPLC-Q-TOF/MS

Du Zhong Formula (DZF), a traditional Chinese medicine formula derived from BeiJiQianJinYaoFang, is used to treat kidney deficiency and lumbago. In this study, ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometer (UPLC-Q-TOF/MS) technique combined with pattern recognition analysis was applied for analysis of metabolic profiles of the bioactive components of the DZF in rat biological samples. In this experiment, a total of 73 compounds, including 53 prototype components and 20 metabolites, were identified tentatively in vivo compared with blank urine, plasma, feces, and cerebrospinal fluid (CSF). The prototype ingredients in DZF include terpenoids, gingerols, phenylpropanoids, alkaloids, phenanthrenes, bibenzyls, organic acids, and other ingredients. The metabolic pathways of DZF involved reduction, demethylation, hydroxylation, desugarization, deoxygenation, glucuronidation, sulfation, and methylation. The proposed method could develop an integrated template approach to analyze screening and identification of the bioactive components in plasma, urine, feces, and CSF after oral administration of herb medicines. Additionally, this investigation might provide helpful chemical information for further pharmacology and activity mechanism of DZF.

Natural Composition and Biosynthetic Pathways of Alkaloids in Medicinal Dendrobium Species

Dendrobium is the second biggest genus in the Orchidaceae family, some of which have both ornamental and therapeutic values. Alkaloids are a group of active chemicals found in Dendrobium plants. Dendrobine has emerged specific pharmacological and therapeutic properties. Although Dendrobium alkaloids have been isolated and identified since the 1930s, the composition of alkaloids and their biosynthesis pathways, including metabolic intermediates, alkaloid transporters, concrete genes involved in downstream pathways, and associated gene clusters, have remained unresolved scientific issues. This paper comprehensively reviews currently identified and tentative alkaloids from the aspect of biogenic pathways or metabolic genes uncovered based on the genome annotations. The biosynthesis pathways of each class of alkaloids are highlighted. Moreover, advances of the high-throughput sequencing technologies in the discovery of Dendrobium alkaloid pathways have been addressed. Applications of synthetic biology in large-scale production of alkaloids are also described. This would serve as the basis for further investigation into Dendrobium alkaloids.

Beneficial effects of Dendrobium nobile Lindl. Alkaloids (DNLA) on anxiety and depression induced by chronic unpredictable stress in rats

Dendrobium nobile Lindl. alkaloid (DNLA) is effective against animal models of Alzheimer's disease. This study further examined its effect on anxiety and depression produced by chronic unpredictable stress (CUS). Rats were subjected to CUS for 42 days, followed by DNLA treatment (20 mg/kg/day, po) for 28 days. The behavioral tests, histopathology, neurotransmitters and RNA-Seq were examined. DNLA attenuated body weight loss and CUS-induced anxiety/depressive-like behaviors, as evidenced by the elevated-plus-maze test, open-field test and sucrose preference. DNLA alleviated neuronal damage and loss and increased Nissl bodies in the hippocampus CA2 region and cortex. DNLA decreased CUS-elevated 5-hydroxytryptamine, dopamine and monoamine oxidase and catechol-O-methyltransferase activities in the brain. DNLA attenuated HPA activation by decreasing adrenocorticotropic hormones and the expression of corticotropin-releasing hormone receptor-1, and increased the expression of glucocorticoid receptor in the brain. RNA-Seq revealed distinct gene expression patterns among groups. Gene ontology revealed the cell projection assembly, postsynapse and centrosome as top biological processes, and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed the cAMP, cGMP-PKG, glutamatergic synapse and circadian as major pathways for DNLA effects. Using DESeq2, CUS modulated 1700 differentially expressed genes (DEGs), which were prevented or attenuated by DNLA. CUS-induced DEGs were highly correlated with the Gene Expression Omnibus (GEO) database for anxiety and depression and were ameliorated by DNLA. Taken together, DNLA attenuated anxiety/depression-like behavior and neuronal damage induced by CUS in rats. The mechanisms could be related to regulation of the monoamine neurotransmitters and the HPA axis, and modulation of gene expression in the hippocampus.

Protective Effects and Mechanisms of Dendrobium nobile Lindl. Alkaloids on PC12 Cell Damage Induced by Aβ 25-35

Background

Aβ deposition abnormally in the mitochondria can damage the mitochondrial respiratory chain and activate the mitochondrial-mediated apoptosis pathway, resulting in AD-like symptoms.

Objective

To observe the protective effects of Dendrobium nobile Lindl. alkaloids (DNLA) on Aβ_25-35-induced oxidative stress and apoptosis in PC12 cells explore its possible protective mechanisms.

Methods

PC12 cells were treated with DNLA with different concentrations (0.035 mg/L, 0.3 mg/L, and 3.5 mg/L) for 6 h, followed by administration with Aβ_25-35 (10 μM) for 24 h. MTT assay and flow cytometer observe the effect of DNLA on Aβ_25-35-induced cytotoxicity and apoptosis of PC12 cell. Based on the mitochondrial apoptosis pathway to study the antiapoptotic effect of DNLA on this model and its relationship with oxidative stress, flow cytometer detected the level of reactive oxygen species (ROS), and ELISA kits were used to detect superoxide dismutase activity (SOD) and glutathione (GSH) content in cells. The JC-1 fluorescent staining observed the effect of DNLA on the mitochondrial membrane potential (MMP) with inverted immunofluorescence microscopy. Western blot was used to detect the levels of mitochondrial apoptosis pathway-related protein and its major downstream proteins Bax, Bcl-2, cleaved-caspase-9, and cleaved-caspase-3.

Results

DNLA can significantly improve the viability and apoptosis rate of PC12 cell damage induced by Aβ_25-35. It also can restore the reduced intracellular ROS content and MMP, while SOD activity and GSH content increase significantly. The expression of apoptosis-related protein Bax, cleaved-caspase-9, and cleaved-caspase-3 decreased when the Bcl-2 protein expression was significantly increased.

Conclusion

These findings suggest that it can significantly inhibit the apoptosis of PC12 cell damage induced by Aβ_25-35. The mechanism may reduce the level of cellular oxidative stress and thus inhibit the mitochondrial-mediated apoptosis pathway.

Dendrobine Inhibits γ-Irradiation-Induced Cancer Cell Migration, Invasion and Metastasis in Non-Small Cell Lung Cancer Cells

The use of ionizing radiation (IR) during radiotherapy can induce malignant effects, such as metastasis, which contribute to poor prognoses in lung cancer patients. Here, we explored the ability of dendrobine, a plant-derived alkaloid from Dendrobium nobile, to improve the efficacy of radiotherapy in non-small cell lung cancer (NSCLC). We employed Western blotting, quantitative real-time (qRT)-PCR, transwell migration assays, and wound-healing assays to determine the effects of dendrobine on the migration and invasion of A549 lung cancer cells in vitro. Dendrobine (5 mm) inhibited γ-irradiation-induced migration and invasion of A549 cells by suppressing sulfatase2 (SULF2) expression, thus inhibiting IR-induced signaling. To investigate the inhibitory effects of dendrobine in vivo, we established a mouse model of IR-induced metastasis by injecting BALB/c nude mice with γ-irradiated A549 cells via the tail vein. As expected, injection with γ-irradiated cells increased the number of pulmonary metastatic nodules in mice (0 Gy/DPBS, 9.8 ± 1.77; 2 Gy/DPBS, 20.87 ± 1.42), which was significantly reduced with dendrobine treatment (2 Gy/Dendrobine, 10.87 ± 0.71), by prevention of IR-induced signaling. Together, these findings demonstrate that dendrobine exerts inhibitory effects against γ-irradiation-induced invasion and metastasis in NSCLC cells in vitro and in vivo at non cytotoxic concentrations. Thus, dendrobine could serve as a therapeutic enhancer to overcome the malignant effects of radiation therapy in patients with NSCLC.

Identification, Biological Activities and Biosynthetic Pathway of Dendrobium Alkaloids

Dendrobium is a genus of flowering plants belonging to the Orchidaceae family with more than 1,400 species. Many Dendrobium species have been used as medicinal plants in several Asian countries for thousands of years. Alkaloids were reported as the major biological markers due to their complex chemical compositions and various types. In this review, we summarized the structural types of alkaloids, their pharmacological activities, as well as the mechanisms of biological activities. More than sixty alkaloids were isolated and identified from the Dendrobium genus. Moreover, the pharmacological effects of Dendrobium alkaloids as hepatic lipid and gluconeogenesis regulation, as neuroprotection, and as anti-tumor, anti-inflammatory, anti-diabetes, and anti-virus factors were described. Besides, the total chemical synthesis of dendrobine is provided, while the biosynthetic pathway of dendrobine has been proposed based on the functions of associated genes. For applications of these invaluable herbs, more researches on the extraction of biological markers from compounds are needed. Further confirmation of the proposed biosynthetic pathways is anticipated as well.

Prebiotic Lactulose Ameliorates the Cognitive Deficit in Alzheimer's Disease Mouse Model through Macroautophagy and Chaperone-Mediated Autophagy Pathways

Lactulose, as a prebiotic, can be utilized by human gut microbiota and stimulate their growth. Although microbiota modulation has become an emerging approach to manage many diseases and can be achieved by the administration of prebiotics, fewer investigations have been carried out on the therapeutic mechanism of lactulose. Two trehalose analogs, lactulose and melibiose, were identified as having a neuroprotective effect in polyglutamine and Parkinson disease models. In this study, we examined lactulose and melibiose in a mouse primary hippocampal neuronal culture under the toxicity of oligomeric Aβ_25-35. Lactulose was further tested in vivo because its effective concentration is lower than that of melibiose. Lactulose and trehalose were applied individually to mice before a bilateral intrahippocampal CA1 injection of oligomeric Aβ_25-35. The administration of lactulose and trehalose attenuated the short-term memory and the learning retrieval of Alzheimer's disease (AD) mice. From a pathological analysis, we found that the pretreatment of lactulose and trehalose decreased neuroinflammation and increased the levels of the autophagic pathways. These results suggest that the neuroprotective effects of both lactulose and trehalose are achieved through anti-inflammation and autophagy. In addition, lactulose was better than trehalose in the enhancement of the synaptic protein expression level in AD mice. Therefore, lactulose could potentially be developed into a preventive and/or therapeutic disaccharide for AD.

RNA-Seq analysis of the protection by Dendrobium nobile alkaloids against carbon tetrachloride hepatotoxicity in mice

OBJECTIVE

Dendrobium nobile is a genuine Chinese medicine. Dendrobium nobile Lindl. alkaloids (DNLA) protects against CCl₄-induced acute liver injury. This study used RNA-Seq to explore the mechanisms.

METHODS

Mice were pretreated with DNLA (10 and 20 mg/kg, po) for 7 days, and subsequently intoxicated with CCl₄ (20 μL/kg, ip for 24 h). Liver RNA was extracted and subjected to RNA-Seq. The bioinformatics, including PCA, GO, KEGG, two-dimensional clustering, Ingenuity Pathways Analysis (IPA), and Illumina BaseSpace Correlation Engine (BSCE) were used to analyze the data. qPCR was performed on selected genes to verify RNA-Seq results.

RESULTS

DNLA protection against CCl₄ hepatotoxicity was confirmed by histopathology. PCA revealed the distinct gene expression patterns between the different treatment groups. GO showed that CCl₄ induced the activation, adhesion and proliferation of immune cells. KEGG showed CCl₄ induced oxidative stress, diseases and compromised adaptive responses. CCl₄ induced differentially expressed genes (DEGs) were identified by DESeq2 with Padj < 0.05 and 2D-clustered with other groups. DNLA reverted CCl₄-induced DEGs in a dose-dependent manner. qPCR analysis of S100 g, Sprr1, CCL3/7, Saa2/3, IL1rn, Cox7a2 and Rad15 confirmed RNA-Seq results. IPA showed that CCl₄ treatment altered some signaling and metabolic pathways, which were ameliorated or returned to normal following DNLA treatment. The CCl₄-activated mitochondrial oxidative phosphorylation was illustrated as an example. IPA Upstream Regulator Analysis further revealed the activated or inhibited molecules and chemicals that are responsible for CCl₄-induced DEGs, and DNLA attenuated these changes. BSCE analysis verified that CCl₄-induced DEGs were highly correlated with the GEO database of CCl₄ hepatotoxicity in rodents, and DNLA dose-dependently attenuated such correlation.

CONCLUSION

RNA-Seq revealed CCl₄-induced DEGs, disruption of canonical pathways, activation or inhibition of upstream regulators, which are highly correlated with database for CCl₄ hepatotoxicity. All these changes were attenuated or returned to normal by DNLA, demonstrating the mechanisms for DNLA to protect against CCl₄ hepatotoxicity.

The Cognitive-Enhancing Effects of Dendrobium nobile Lindl Extract in Sleep Deprivation-Induced Amnesic Mice

Chronic sleep deprivation (SD) causes neurological and neurodegenerative dysfunction including learning and memory deficit. The orchid Dendrobium nobile Lindl (DNL), is widely used as a Yin tonic and medicinal food throughout Asia, and has many reported pharmacological effects. This study focused on the cognitive-enhancing effects of DNL in sleep deprivation-induced amnesia in mice and its biochemical mechanisms. Our results showed that the mice displayed significant cognitive deficits after 2-week SD while treatment with the extract of DNL prevented these impairments. In the novel object recognition and object location recognition tasks, a significant increase in the discrimination index was observed in DNL-treated (200 and 400 mg/kg) mice. In the MWM test, DNL (200 and 400 mg/kg) treatment shorten the prolongation of latency and increased the crossing numbers compared with SD mice. The biochemical analysis of brain tissue showed a decrease in NE, dismutase (T-SOD) and catalase (CAT) activity and an increase in 5-HT and malondialdehyde (MDA) concentration after the treatment with DNL in mice. Our findings indicated that DNL exerted a positive effect in preventing and improving cognitive impairment induced by SD, which may be mediated via the regulation of neurotransmitters and alleviation of oxidative stress.

Natural Products for the Treatment of Neurodegenerative Diseases

Neurodegenerative diseases are a heterogeneous group of disorders characterized by the progressive degeneration of the structure and function of the central nervous system or peripheral nervous system. Alzheimer's Disease (AD), Parkinson's Disease (PD) and Spinal Cord Injury (SCI) are the common neurodegenerative diseases, which typically occur in people over the age of 60. With the rapid development of an aged society, over 60 million people worldwide are suffering from these uncurable diseases. Therefore, the search for new drugs and therapeutic methods has become an increasingly important research topic. Natural products especially those from the Traditional Chinese Medicines (TCMs), are the most important sources of drugs, and have received extensive interest among pharmacist. In this review, in order to facilitate further chemical modification of those useful natural products by pharmacists, we will bring together recent studies in single natural compound from TCMs with neuroprotective effect.

Dendrobium nobile Lindl alkaloid attenuates 6-OHDA-induced dopamine neurotoxicity

Parkinson's disease (PD) is one of the most common central nervous system (CNS) degenerative disease and is characterized by a progressive loss of midbrain substantia nigra dopamine (DA) neurons. Dendrobium nobileLindl alkaloid (DNLA) is an active component extracted from D. nobile Lindl, which is a traditional Chinese herb. The various pharmacological effects of D. nobile are beneficial for human health. Recently, DNLA-mediated neuroprotective effects have been reported. However, the neuroprotection of DNLA on 6-hydroxydopamine (6-OHDA)-induced DA neurotoxicity is still unknown. This study aimed to explore the neuroprotective effects of DNLA on DA neurotoxicity induced by 6-OHDA. In PD rat model, continuous intragastric administration of DNLA (20 mg/kg) for 7 days significantly ameliorated 6-OHDA-induced DA neurons loss in the midbrain substantia nigra. In addition, primary rat midbrain neuron-glia cocultures were used to explore the mechanisms underlying DNLA-related DA neuroprotection. The studies on neuron-glia cocultures revealed that neuroprotective effects of DNLA (2.5 ng/mL) were mediated by inhibiting the release of proinflammatory cytokines. Taken together, DNLA holds neuroprotective effect on 6-OHDA-induced neurons neurodegeneration by selectively inhibiting the production of proinflammatory factors and could be a potential compound for PD treatment.

Astragaloside IV prevents Aβ1-42 oligomers-induced memory impairment and hippocampal cell apoptosis by promoting PPARγ/BDNF signaling pathway

Astragaloside IV (AS-IV), a natural product derived from Radix Astragali (Astragalus membranaceus), is beneficial for the treatment of Alzheimer's disease (AD), but the mechanisms underlying this benefit are not completely understood. Peroxisome proliferator-activated receptor gamma (PPARγ) and brain-derived neurotrophic factor (BDNF) are potential therapeutic targets for AD. In this study, we found that amyloid β protein fragment 1-42 oligomers (AβO) suppressed BDNF and PPARγ expression, and inhibited tyrosine receptor kinase B (TrkB) phosphorylation in cultured hippocampal neurons; these changes were ameliorated by treatment with AS-IV. Inhibition of PPARγ by genetic and pharmacological methods also blocked the effect of AS-IV on BDNF expression in AβO-treated cells. Importantly, exogenous BDNF protected against neurotoxicity and apoptosis induced by AβO, whereas inhibition of PPARγ reversed protective effects of AS-IV against these outcomes. In vivo data further revealed that AS-IV improved AβO-induced memory impairment and reduced apoptosis of hippocampal neurons. Moreover, AS-IV suppressed the AβO-induced reduction in BDNF by promoting PPARγ activation in the hippocampus. Taken together, these results indicate that AS-IV prevents AβO-induced memory impairment and hippocampal neuronal apoptosis, probably by promoting the PPARγ/BDNF signaling pathway.

Human umbilical cord mesenchymal stem cells-derived exosomes deliver microRNA-375 to downregulate ENAH and thus retard esophageal squamous cell carcinoma progression

Background

Exosomal microRNAs (miRNAs or miRs) from bone marrow-derived mesenchymal stem cells (UCMSCs) have emerged as promising therapeutic strategies for cancer treatment. The current study aimed to elucidate the underlying mechanism of human umbilical cord mesenchymal stem cells (hUCMSCs)-derived exosomal miR-375 in esophageal squamous cell carcinoma (ESCC).

Methods

After determining the expression of miR-375 and its putative target enabled homolog (ENAH) in ESCC tissues and cells, we tested effects of their altered expression on ESCC proliferation, invasion, migration, and tumorsphere formation was subsequently measured. Transfected hUCMSCs-derived exosomes (hUCMSCs-exo) were isolated and co-cultured with ESCC cells to measure the effects of miR-375 delivered by hUCMSCs-exo on ESCC development. Finally, we investigated the effect of miR-375 on tumor growth in vivo.

Results

The expression of miR-375 was reduced, while the expression of ENAH was elevated in ESCC. ENAH was identified as a target gene of miR-375. Elevated miR-375 or depleted ENAH expression inhibited ESCC cell proliferation, invasion, migration, tumorsphere formation, and promoted apoptosis. Moreover, miR-375 delivered by hUCMSCs-exo could suppress ESCC cell proliferation, invasion, migration, tumorsphere formation, but promoted apoptosis in vitro, as well as inhibiting tumor growth in vivo.

Conclusions

Taken together, hUCMSCs-exo can deliver miR-375 to suppress ENAH expression and subsequently inhibit the initiation and progression of ESCC.

Anti-aging properties of Dendrobium nobile Lindl.: From molecular mechanisms to potential treatments

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium Nobile Lindl. (DNL) is one of the central herbs in traditional Chinese medicine which mainly distributes in Guizhou, Yunnan, Guangxi and other sub-tropical areas south of the Yangtze River. In the past decades, it has been used to treat tumors, hyperglycemia, hyperlipidemia, and diseases of the nervous system that may be caused by aging.

AIM OF THE REVIEW

The purpose of this review is to summarize the anti-aging information of DNL from the molecular mechanism level, including classic theories related to aging, main chemical components, pharmacological research and anti-aging theory based on traditional Chinese medicine theory, for exploring the future development and clinical treatment.

MATERIALS AND METHODS

The information in this paper has been collected from the scientific literature databases including PubMed, Google Scholar, Web of Science, Science Direct, Springer, China National Knowledge Infrastructure, published books, Ph.D. and M.S. dissertations systematically.

RESULTS

In this paper, we have reviewed the several mechanisms underlying the potential effects of DNL on the prevention of aging, including the scavenging of free radicals for oxidation, delaying of DNA impairment, inhibition of apoptosis, and alteration of DNA methylation. Together with the theory of telomeres, this review also has summarized recent research progress in the use of DNL and its traditional efficacy.

CONCLUSIONS

We conclude that "strengthening Yin and benefiting the spirit", "thickening the intestine and stomach", "lightning the body and prolonging the life-span", and delaying aging, are key effects of DNL that can be used to combat age-related diseases (ARDs) such as Alzheimer's disease, hyperlipidemia, and diabetes. This review provides a reference for future study of ARDs and the clinical application of DNL.

Dendrobium nobile Lindl. alkaloids-mediated protection against CCl4-induced liver mitochondrial oxidative damage is dependent on the activation of Nrf2 signaling pathway

The activation of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated signaling pathway has been involved in the mechanisms of a variety of protective agents against cellular oxidative stress. We recently demonstrated that Dendrobium nobile Lindl. alkaloids (DNLA), the active ingredients of Dendrobium, protects mice from CCl₄-induced liver injury, dependent on the Nrf2 signaling pathway. The present study was aimed to determine whether the protection against mitochondrial oxidative damage plays a role in the mode of action of DNLA on CCl₄-induced liver injury, and to further investigate whether the DNLA-conferred mitochondrial beneficial effects is dependent on the activation of Nrf2 signaling. The CCl₄-induced acute liver injury model was employed in both wild-type (WT) and Nrf2-knockout (Nrf2^-/-) mice. The results showed that in WT mice DNLA reduced CCl₄-induced liver injury, accompanied by a significant reduction in CCl₄-induced mitochondrial oxidative stress as evidenced by a decrease in mitochondrial H₂O₂ content and MDA production, and a marked increase in GSH level and Mn-SOD activity. However, these protective effects were significantly attenuated in Nrf2^-/- mice. Furthermore, the administration of DNLA improved mitochondrial oxygen consumption, elevated ATP production, and decreased CCl₄-induced apoptosis in the WT mice, whereas the DNLA-mediated protections on mitochondrial function were diminished in the Nrf2 null mice. These results demonstrate that the improvement of mitochondrial oxidative stress and mitochondrial dysfunction is implicated in the mechanism of DNLA-mediated protection on CCl₄-induced liver injury, and this DNLA-modulated mode of action is dependent on the activation of Nrf2 signaling pathway.

Dendrobium nobile Lindl alkaloid and metformin ameliorate cognitive dysfunction in senescence-accelerated mice via suppression of endoplasmic reticulum stress

The senescence-accelerated mouse prone 8 (SAMP8) mice have many pathological features of Alzheimer's disease (AD) with aging. We previously reported that Dendrobium nobile Lindl alkaloid (DNLA) effectively improved cognitive deficits in multiple Alzheimer's disease (AD) models. This study further used SAMP8 mice to study the anti-aging effects of DNLA, focusing on endoplasmic reticulum (ER) stress. DNLA and metformin were orally administered to SAMP8 mice starting at 4-month of age for 6 months. Behavioral tests were performed in 10-month-old SAMP8 mice and age-matched SAMR1 control mice. At the end of experiment, neuron damage was evaluated by histology and transmission electron microscopy. ER stress-related proteins were analyzed with Western-blot. DNLA improved learning and memory impairments, reduced the loss of neurons and Nissl bodies in the hippocampus and cortex. DNLA ameliorated ER dilation and swelling in the hippocampal neurons. DNLA down-regulated the protein kinase RNA-like endoplasmic reticulum kinase (PERK) signaling pathway, decreased calpain 1, GSK-3β and Cdk5 activities and the Tau hyper-phosphorylation. The effects of DNLA were comparable to metformin. In summary, DNLA was effective in improving cognitive deficits in aged SAMP8 mice, possibly via suppression of ER stress-related PERK signaling pathway, sequential inhibition of calpain 1, GSK-3β and Cdk5 activities, and eventually reducing the hyper-phosphorylation of Tau.

Puerariae Radix Prevents Anxiety and Cognitive Deficits in Mice Under Oligomeric Aβ-Induced Stress

To evaluate the therapeutic effects of Chinese herbal medicine (CHM) for Alzheimer's disease (AD), we evaluated five CHMs in oligomeric Aβ25-35-treated mouse primary hippocampal neuronal cultures. The aqueous extract from the root of Pueraria lobata (Puerariae Radix; PR) showed better neuroprotective effects than did the other four CHM aqueous extracts, including Gardenia jasminoides, Eleutherococcus senticosus, Rhodiola rosea, and Panax, in the primary culture treated with saline or oligomeric Aβ25-35. Furthermore, the neuroprotective effects of aqueous extract of PR were also better than its well-known active compound, puerarin, against the neurotoxicity of oligomeric Aβ25-35 in a primary culture. For in vivo experiments, C57BL/6J male mice that received direct infusion of soluble oligomeric Aβ25-35 into the bilateral hippocampal CA1 subregion were used as an alternative AD mouse model. The effects and molecular mechanisms of chronic systemic administration of PR aqueous extract were evaluated in the alternative AD model. PR aqueous extract prevented anxiety and cognitive impairment in mice associated with a decrease in the levels of Aβ deposition, tau protein phosphorylation, inflammation, loss of noradrenergic, and serotonergic neurons and an increase in the levels of synaptophysin and insulin degrading enzyme (IDE) against the toxicity of oligomeric Aβ25-35. Furthermore, no obvious damage to the liver and kidney was detected after chronic systemic administration of PR aqueous extract. Therefore, using PR could be a safer, more effective therapeutic strategy than using its active compound puerarin to prevent both cognitive and noncognitive dysfunction and related pathological features of AD.

New Insights into Detection of a Dendrobine Compound From a Novel Endophytic Trichoderma longibrachiatum Strain and Its Toxicity Against Phytopathogenic Bacteria

Dendrobium nobile is the only plant that could produce the natural bioactive dendrobine. No other source of dendrobine has been found to date except from D. nobile and via chemical synthesis. In this study, we aimed to examine the potential fungal endophyte isolated from D. nobile stem segments using the molecular method and to detect dendrobine compound through high-performance liquid chromatography (HPLC), gas chromatography–mass spectrometry (GC-MS), and liquid chromatography with tandem mass spectrometry (LC-MS/MS) and their metabolite for their antibacterial activity. The potential dendrobine producer strain was recognized as Trichoderma longibrachiatum based on molecular DNA sequencing and GenBank databases. The T. longibrachiatum MD33 produced dendrobine and other compounds in a potato dextrose medium (PDM), as confirmed by HPLC retention time peak analysis. The HPLC results revealed that T. longibrachiatum MD33 biomass showed a peak retention time of 5.28 ± 0.2 min, similar to wild D. nobile stem dendrobine (5.32 ± 0.2 min) and standard chemical reference dendrobine (5.30 ± 0.2 min), indicating the presence of dendrobine in the fungal biomass. Results of GC-MS and LC-MS analysis revealed that T. longibrachiatum MD33 produced the same molecular weight (263 in GC-MS and 264.195 in LC-MS) of dendrobine as compared with standard chemical reference dendrobine and D. nobile dendrobine. Antibacterial activity data revealed that T. longibrachiatum MD33 produced the strongest bactericidal activity against Bacillus subtilis, Bacillus mycoides, and Staphylococcus species, and the diameter of the bacterial growth inhibition zone was 12 ± 0.2, 9 ± 0.2, and 8 ± 0.2 mm, respectively. To the best of our knowledge, this was the first study to investigate T. longibrachiatum as a dendrobine producer, and the results revealed that T. longibrachiatum was directly involved in the potential production of a similar bioactive compound to D. nobile (dendrobine). In addition, the T. longibrachiatum metabolite exhibited potent antibacterial activity and can be a potential strain for medical and industrial purposes.

EPA-enriched ethanolamine plasmalogen and EPA-enriched phosphatidylethanolamine enhance BDNF/TrkB/CREB signaling and inhibit neuronal apoptosis in vitro and in vivo

Our previous study showed that EPA-enriched ethanolamine plasmalogen (EPA-pPE) exerted more significant effects than EPA-enriched phosphatidylethanolamine (EPA-PE) in improving learning and memory deficit. However, the results of the mechanism study were not consistent with the improved cognitive function, which suggested that other signaling pathways might be involved. In the present study, primary cultured hippocampal neurons and cognitive deficiency rats were used to compare the effects of EPA-pPE and EPA-PE on brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB)/cAMP response element-binding protein (CREB) signaling and neuronal apoptosis. The in vitro experiment showed that both EPA-pPE and EPA-PE could relieve cell death and improve the cellular morphology of neurons via upregulating anti-apoptotic proteins and downregulating pro-apoptotic proteins. The in vivo experiment showed that EPA-pPE exerted more significant effects than EPA-PE in improving the number of neuronal Nissl bodies, increasing the branching of dendrites and dendritic spine density in cortical neurons, as well as improving the expression of synaptic vesicle-related proteins synaptophysin (SYN) and PSD95 via BDNF/TrkB/CREB signaling. These results indicated that EPA-pPE exerted neuroprotection at least partly through inhibiting neuronal apoptosis and enhancing the BDNF/TrkB/CREB pathway, which suggests that EPA-enriched plasmalogen can be explored as a potential therapeutic agent in long-term Alzheimer's disease therapy.

Alkaloids of dendrobium nobile lindl. Altered hepatic lipid homeostasis via regulation of bile acids

ETHNOPHARMACOLOGICAL RELEVANCE

Accumulation of hepatic lipid promotes systemic metabolic dysfunction and results in fatty liver. Our previous studies have shown that the alkaloids of Dendrobium nobile Lindl. (DNLA) could regulate the lipid metabolism gene expression in livers of mice. However, the protective effects on hepatic lipid homeostasis and the underlying mechanisms are still unclear.

MATERIALS AND METHODS

The C57BL/6 male mice were randomly divided into four groups, including control group, model group, DNLA treatment group, and simvastatin positive control group. Mice in the control group and the other three groups were fed with control diet and high fat diet during the full course of this study, respectively. Hepatic lipid accumulation was induced by HFD in mice after 18 weeks of feeding. DNLA (15 mg/kg) and simvastatin (20 mg/kg) were administrated intragastrically in the DNLA treatment group and simvastatin positive control group for another 18 weeks, respectively. HE staining and Oil-Red-O staining of liver tissues were observed. TC and TG levels in liver were assayed. The amount of major bile acids in mice livers were quantified by UPLC-MS. Expression levels of genes were tested by the real-time PCR.

RESULTS

The results of HE staining and Oil-Red-O staining showed that DNLA could improve hepatic lipid homeostasis. DNLA significantly decreased liver TC and TG levels in the DNLA group. Moreover, the UPLC-MS analysis showed that DNLA did not only influence the hepatic bile acid quantity but did raise the hydrophilicity. Compared with the model group, DNLA decreased the hepatic levels of several free bile acids, including LCA, DCA, CA, and CDCA, and increased most important taurine-conjugated bile acids levels in liver, including TMCAs, TCDCA, TUDCA, and THDCA. In addition, DNLA also decreased the CA/CDCA ratio. The gene expression levels of Cyp27a1, Cyp3a11, Fxr, and Shp were up-regulated in DNLA treatment group.

CONCLUSION

DNLA may improve the hepatic abnormal lipid profile of HFD-fed mice via two pathways: (1) enhancing the taurine-conjugated bile acids which are highly hydrophilic and contribute to the excretion of cholesterol; (2) decreasing the CA/CDCA ratio which is positively related to cholesterol absorption.

Dendrobium alkaloids decrease Aβ by regulating α- and β-secretases in hippocampal neurons of SD rats

Background

Alzheimer's disease (AD) is the primary cause of dementia in the elderly. The imbalance between production and clearance of amyloid β (Aβ) is a very early, often initiating factor in AD. Dendrobium nobile Lindl. alkaloids (DNLA) extracted from a Chinese medicinal herb, which have been shown to have anti-aging effects, protected against neuronal impairment in vivo and in vitro. Moreover, we confirmed that DNLA can improve learning and memory function in elderly normal mice, indicating that DNLA has potential health benefits. However, the underlying mechanism is unclear. Therefore, we further explored the effect of DNLA on neurons, which is closely related to learning and memory, based on Aβ.

Methods

We exposed cultured hippocampal neurons to DNLA to investigate the effect of DNLA on Aβ in vitro. Cell viability was evaluated by MTT assays. Proteins were analyzed by Western blot analysis.

Results

The cell viability of hippocampal neurons was not changed significantly after treatment with DNLA. But DNLA reduced the protein expression of amyloid precursor protein (APP), disintegrin and metalloprotease 10 (ADAM10), β-site APP cleaving enzyme 1 (BACE1) and Aβ_1-42 of hippocampal neurons in rats and increased the protein expression of ADAM17.

Conclusions

DNLA decreases Aβ by regulating α- and β-secretase in hippocampal neurons of SD rats.

Induction of Nrf2 pathway by Dendrobium nobile Lindl. alkaloids protects against carbon tetrachloride induced acute liver injury

Dendrobium nobile Lindl. alkaloids (DNLA), the active ingredients of Dendrobium, has been shown to possess anti-oxidative effects. The nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant signaling pathway plays a critical role in the cellular response to oxidative stress. Oxidative damage has been implicated in the mechanism of various hepatotoxins induced liver injury. The present study aimed to examine the protective effects of DNLA on CCl₄-induced acute liver injury, and to explore the role of the Nrf2 pathway in the protective action of DNLA. Wild-type (WT) and Nrf2-knockout (Nrf2^-/-) mice were administrated with DNLA (20 mg/kg/day, ig) for 7 days, and then challenged with CCl₄ (20 μL/kg, ip). In WT mice, DNLA reduced CCl₄ induced liver injury, as evidenced by the reduction in the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), attenuation of malondialdehyde (MDA) production, and improved ultrastructural morphology in hepatocytes. However, the protective effect was diminished in Nrf2^-/- mice, indicating an essential role of Nrf2 in DNLA-mediated protection over CCl₄ liver injury. Furthermore, it was found that DNLA enhanced Nrf2 expression and nuclear accumulation and increased the expression of Nrf2 regulated downstream proteins. These results demonstrate that DNLA protects mice from CCl₄ induced liver injury, probably through the activation of the Nrf2 signaling pathway.

Co-expression Network Analysis Revealing the Potential Regulatory Roles of lncRNAs in Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common types of dementia among the elderly. Previous studies had revealed that the dysregulation of lncRNAs played important roles in human diseases, including AD. However, there is still a lack of comprehensive analysis of differently expressed long non-coding RNAs (lncRNAs) in different distinct regions related to AD. In present study, we identified a total of 678, 593, 941, 1445, 1179, 466 differently expressed lncRNAs that were found in entorhinal cortex (EC), middle temporal gyrus(MTG), hippocampus (HIP), superior frontal gyrus (SFG), posterior cingulate (PC), cortex and primary visual cortex (VCX) AD samples, respectively. Furthermore, we constructed lncRNA-mRNA co-expression networks in AD to explore the potential roles of these lncRNAs. Differentially expressed (DE) lncRNAs were involved in regulating metabolic process, respiratory electron transport chain and ATP metabolic process showed by GO analysis. Interestingly, KEGG analysis revealed these lncRNAs were associated with neurodegenerative disorders such as Alzheimer's disease, Huntington's disease and Parkinson's disease. Four lncRNAs (LOC100507557, LOC101929787, NEAT1, and JAZF1-AS1) were identified as key lncRNAs in AD progression and dysregulated in different distinct regions related to AD. Our study has uncovered several key lncRNAs in AD, which would give novel underlying therapeutic and prognostic targets for AD.

Dendrobium nobile Lindl. Alkaloids Decreases the Level of Intracellular β-Amyloid by Improving Impaired Autolysosomal Proteolysis in APP/PS1 Mice

As the major degradation pathway for long-lived proteins and organelles, macroautophagy is a decisive factor for the survival and longevity of cells. The existing evidence indicates that the disruption of substrate proteolysis in autolysosomes is the main mechanism underlying autophagy failure in Alzheimer’s disease (AD). Thus, the restoration of normal lysosomal proteolysis and autophagy efficiency is a novel therapeutic strategy in the treatment of AD. In this study, 9-month-old APPswe/PS1ΔE9 transgenic (APP/PS1) mice were administered Dendrobium nobile Lindl. alkaloids (DNLA, 40 and 80 mg/kg) or Metformin (80 mg/kg), and age-matched wild-type mice were administered an isovolumic vehicle orally once a day for 4 months. The results demonstrated that DNLA significantly improved learning and memory function in APP/PS1 transgenic mice in the Morris water maze. Furthermore, DNLA could increase the expression of the v-ATPase A1 subunit to facilitate lysosomal acidification, prompt the dissociation of the cation independent-mannose-phosphate receptor from cathepsin (cat) D, promote the proteolytic maturation of cat D, increase the degradation of accumulated autophagic vacuoles (AVs) and β-amyloid (Aβ) contained in the AVs, and alleviate neuronal and synaptic injury. These findings demonstrate that DNLA improves learning and memory function in APP/PS1 mice, and the mechanisms appear to be due to the promotion of intracellular Aβ degradation by increasing the protein level of v-ATPase A1 and then improving autolysosomal acidification and proteolysis.

Piceatannol attenuates behavioral disorder and neurological deficits in aging mice via activating the Nrf2 pathway

Aging is a complex process that is accompanied by neurological damage. Chronic injection of d-galactose (d-gal) can accelerate the aging process similar to natural aging and is commonly used to build an aging model to investigate aging. In the present study, the effects of piceatannol on d-gal-induced aging in mice were evaluated. Piceatannol treatment showed an observable anti-aging effect. Results obtained in vivo showed that piceatannol retained spontaneous motor activity and enhanced spatial learning and memory abilities in mice in which aging was induced by d-gal. Morphometric analysis displayed that piceatannol prevented d-gal-induced neuronal loss, increased the number of Nissl bodies, and promoted cell proliferation in the hippocampus and cortex. Piceatannol also significantly decreased the level of MDA and elevated SOD and CAT activity in the hippocampal and cortical tissues. Furthermore, western blotting results revealed that piceatannol treatment noticeably reversed the suppression of Nrf2 nuclear translocation and increased the expressions of HO-1 and NOQ1 in mice with aging induced by d-gal. Furthermore, piceatannol activated the Nrf2 pathway in natural aging mice, whereas treatment with the Nrf2 inhibitor brusatol reversed the increased expressions of Nrf2, HO-1, and NOQ1. In conclusion, treatment with piceatannol ameliorates behavioral disorder and brain injury in an aging mouse model; this suggests that piceatannol is a promising pharmaceutical candidate for the treatment of age-associated diseases.