Isorhynchophylline Protects PC12 Cells Against Beta-Amyloid-Induced Apoptosis via PI3K/Akt Signaling Pathway

The beneficial pharmacological effects of Uncaria rhynchophylla in neurodegenerative diseases: focus on alkaloids

With the intensification of aging population, the prevention or treatment of neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease, has drawn more and more attention. As a long used traditional Chinese medicine, Uncaria rhynchophylla (Miq.) Jacks., named Gouteng in Chinese, has been reported to have an effective neuroprotective role in neurodegenerative diseases. In this review, the beneficial pharmacological effects and signaling pathways of herbal formulas containing U. rhynchophylla, especially major compounds identified from U. rhynchophylla, such as corynoxine B, corynoxine, rhynchophylline, and isorhynchophylline, in neurodegenerative diseases, were summarized, which not only provide an overview of U. rhynchophylla for the prevention or treatment of neurodegenerative diseases but also give some perspective to the development of new drugs from traditional Chinese medicine.

Exploring allocryptopine as a neuroprotective agent against oxidative stress-induced neural apoptosis via Akt/GSK-3β/tau pathway modulation

Alzheimer's disease (AD) is characterized by neuronal loss due to hyperphosphorylated proteins induced by oxidative stress. AD remains a formidable challenge in the medical field, as current treatments focusing on single biomarkers have yielded limited success. Hence, there's a burgeoning interest in investigating novel compounds that can target mechanisms, offering alternative therapeutic approaches. The aim of this study is to investigate the effects of allocryptopine, an isoquinoline alkaloid, on mechanisms related to AD in order to develop alternative treatment strategies. In this study, the in vitro AD cell model was obtained by inducing nerve growth factor (NGF)-differentiated PC12 (dPC12) cells to oxidative stress with H2O2, and also the effect mechanism of different allocryptopine concentrations on the in vitro AD cell model was studied. The treatments' antioxidative effects at the ROS level and their regulation of the cell cycle were assessed through flow cytometry, while their anti-apoptotic effects were evaluated using both flow cytometry and qRT-PCR. Additionally, the phosphorylation levels of Akt, GSK-3β, and tau proteins were analyzed via western blot, and the interactions between Akt, GSK-3β, CDK5 proteins, and allocryptopine were demonstrated through molecular docking. Our study's conclusive results revealed that allocryptopine effectively suppressed intracellular ROS levels, while simultaneously enhancing the Akt/GSK-3β signaling pathway by increasing p-Akt and p-GSK-3β proteins. This mechanism played a critical role in inhibiting neural cell apoptosis and preventing tau hyperphosphorylation. Moreover, allocryptopine demonstrated its ability to regulate the G1/S cell cycle progression, leading to cell cycle arrest in the G1 phase, and facilitating cellular repair mechanisms, potentially contributing to the suppression of neural apoptosis. The in silico results of allocryptopine were shown to docking with the cyclin-dependent kinase 5 (CDK 5) playing a role in tau phosphorylation Akt and GSK-3β from target proteins. Therefore, the in silico study results supported the in vitro results. The results showed that allocryptopine can protect dPC12 cells from oxidative stress-induced apoptosis and hyperphosphorylation of the tau protein by regulating the Akt/GSK-3β signaling pathway. Based on these findings, it can be suggested that allocryptopine, with its ability to target biomarkers and its significant effects on AD-associated mechanisms, holds promise as a potential candidate for drug development in the treatment of AD. Further research and clinical trials are recommended in the future.

Alkaloids as drug leads in Alzheimer's treatment: Mechanistic and therapeutic insights

Alzheimer's disease (AD) has few effective treatment options and continues to be a major global health concern. AD is a neurodegenerative disease that typically affects elderly people. Alkaloids have potential sources for novel drug discovery due to their diverse chemical structures and pharmacological activities. Alkaloids, natural products with heterocyclic nitrogen-containing structures, are considered potential treatments for AD. This review explores the neuroprotective properties of alkaloids in AD, focusing on their ability to regulate pathways such as amyloid-beta aggregation, oxidative stress, synaptic dysfunction, tau hyperphosphorylation, and neuroinflammation. The FDA has approved alkaloids such as acetylcholinesterase inhibitors like galantamine and rivastigmine. This article explores AD's origins, current market medications, and clinical applications of alkaloids in AD therapy. This review explores the development of alkaloid-based drugs for AD, focusing on pharmacokinetics, blood-brain barrier penetration, and potential adverse effects. Future research should focus on the clinical evaluation of promising alkaloids, developing recently discovered alkaloids, and the ongoing search for novel alkaloids for medical treatment. A pharmaceutical option containing an alkaloid may potentially slow down the progression of AD while enhancing its symptoms. This review highlights the potential of alkaloids as valuable drug leads in treating AD, providing a comprehensive understanding of their mechanisms of action and therapeutic implications.

Qingxin Kaiqiao Fang decreases Tau hyperphosphorylation in Alzheimer's disease via the PI3K/Akt/GSK3β pathway in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD) belongs to the category of "senile dementia" in traditional Chinese medicine. AD is associated with brain emptiness or collaterals blocked by phlegm-heat. "Fumanjian" from Jingyue Quanshu treats dementia by promoting qi circulation, alleviating depression, eliminating turbidity, cultivating positivity, and dispelling evil spirits. Qingxin Kaiqiao Fang (QKF), derived from Fumanjian, is effective in treating AD owing to previously mentioned clinical effects. Elucidating the mechanism(s) of action of QKF on AD associated with phlegm-heat may be beneficial for therapeutic management; however, further research is needed.

AIM OF THE STUDY

This study aimed to determine the role of the PI3K/Akt pathway in AD, especially the specific effector protein involved, and explore the efficacy of QKF in treating AD by modulating the PI3K/Akt signal.

MATERIALS AND METHODS

High-performance liquid chromatography-Q-orbitrap-mass spectrometry was used to analyze the chemical components of QKF. Subsequently, APP/PS1 double-transgenic mice were used for behavioral tests, and hematoxylin-eosin and Nissl staining were used to assess the neuroprotective and cognitive effects of QKF. Cerebrospinal fluid pharmacology was used in in vitro validation, and Aβ25-35 was used to induce PC12 cells to establish the AD cell model. Various methods, including immunohistochemistry, Western blotting, quantitative real-time polymerase chain reaction, morphological assay, cell counting kit-8(CCK-8) assay, and terminal deoxynucleotide transferase (TdT)-mediated dUTP nick-end labeling (TUNEL)staining, were used to evaluate the effect of QKF on Tau hyperphosphorylation and anti-apoptosis. These methods also assessed the influence of QKF on the PI3K/Akt/GSK3β pathway involving the mRNA and protein expressions. Finally, the inhibitor - LY294002 was used for reverse validation.

RESULTS

We identified 295 chemical components in the water extract of QKF.QKF improved spatial cognition and learning memory in APP/PS1 mice, protected PC12 cell morphology, improved cell survival, reduced Aβ25-35-induced apoptosis, and inhibited the hyperphosphorylation of Tau protein via the PI3k/Akt/GSK3β signaling pathway. Furthermore, this protective effect of QKF was reduced by LY294002 in vitro.

CONCLUSIONS

QKF can improve spatial cognition, learning, and memory abilities in APP/PS1 mice and protect PC12 cells. Decreasing the Tau hyperphosphorylation in AD exhibits curative efficacy on AD via the PI3K/Akt/GSK3β pathway in vitro and in vivo.

Targeting epigenetic and posttranslational modifications regulating ferroptosis for the treatment of diseases

Ferroptosis, a unique modality of cell death with mechanistic and morphological differences from other cell death modes, plays a pivotal role in regulating tumorigenesis and offers a new opportunity for modulating anticancer drug resistance. Aberrant epigenetic modifications and posttranslational modifications (PTMs) promote anticancer drug resistance, cancer progression, and metastasis. Accumulating studies indicate that epigenetic modifications can transcriptionally and translationally determine cancer cell vulnerability to ferroptosis and that ferroptosis functions as a driver in nervous system diseases (NSDs), cardiovascular diseases (CVDs), liver diseases, lung diseases, and kidney diseases. In this review, we first summarize the core molecular mechanisms of ferroptosis. Then, the roles of epigenetic processes, including histone PTMs, DNA methylation, and noncoding RNA regulation and PTMs, such as phosphorylation, ubiquitination, SUMOylation, acetylation, methylation, and ADP-ribosylation, are concisely discussed. The roles of epigenetic modifications and PTMs in ferroptosis regulation in the genesis of diseases, including cancers, NSD, CVDs, liver diseases, lung diseases, and kidney diseases, as well as the application of epigenetic and PTM modulators in the therapy of these diseases, are then discussed in detail. Elucidating the mechanisms of ferroptosis regulation mediated by epigenetic modifications and PTMs in cancer and other diseases will facilitate the development of promising combination therapeutic regimens containing epigenetic or PTM-targeting agents and ferroptosis inducers that can be used to overcome chemotherapeutic resistance in cancer and could be used to prevent other diseases. In addition, these mechanisms highlight potential therapeutic approaches to overcome chemoresistance in cancer or halt the genesis of other diseases.

Isorhynchophylline ameliorates stress-induced emotional disorder and cognitive impairment with modulation of NMDA receptors

Introduction

Isorhynchophylline is one of the main active ingredients from Uncaria rhynchophylla, the effects and mechanisms of isorhynchophylline on stress-induced emotional disorders and cognitive impairment remain unclear.

Methods

Long-term potentiation (LTP) in vivo was used for synaptic plasticity evaluation; chronic unpredictable mild stress (CUMS) model was used to evaluate the effect of isorhynchophylline on stress induced emotional disorders and cognitive impairment; sucrose preference test (SPT), open field test (OFT), and elevated plus maze (EPM) were used to evaluate emotional disorders; morris water maze (MWM) test was used to evaluate cognitive impairment; Western blotting (WB) was used to the expression of proteins; high performance liquid chromatography (HPLC) was used to quantify neurotransmitters; Nissl staining was used to identify pathological changes induced by stress.

Results

In this study, we found that isorhynchophylline improved corticosterone-induced in vivo LTP impairment significantly, indicating positive effects on stress. Therefore, 28-day CUMS model was adopted to evaluate the anti-stress effects of isorhynchophylline. The results showed that isorhynchophylline improved CUMS-induced weight loss, anxiety- and depression-like behaviors, and spatial memory impairment. Isorhynchophylline reduced CUMS-induced corticosterone elevation. N-methyl-D-aspartic acid (NMDA) receptors play an important role in the process of emotion and memory. Glutamate and the expression of GluN2B increased in the CUMS mice, while D-serine and the expression of serine racemase (SR) decreased significantly, and isorhynchophylline restored these changes to normal level.

Conclusion

These results indicated that isorhynchophylline ameliorated stress-induced emotional disorders and cognitive impairment, modulating NMDA receptors might be one of the underlying mechanisms.

Regulation of mitochondrial dysfunction induced cell apoptosis is a potential therapeutic strategy for herbal medicine to treat neurodegenerative diseases

Neurodegenerative disease is a progressive neurodegeneration caused by genetic and environmental factors. Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD) are the three most common neurodegenerative diseases clinically. Unfortunately, the incidence of neurodegenerative diseases is increasing year by year. However, the current available drugs have poor efficacy and large side effects, which brings a great burden to the patients and the society. Increasing evidence suggests that occurrence and development of the neurodegenerative diseases is closely related to the mitochondrial dysfunction, which can affect mitochondrial biogenesis, mitochondrial dynamics, as well as mitochondrial mitophagy. Through the disruption of mitochondrial homeostasis, nerve cells undergo varying degrees of apoptosis. Interestingly, it has been shown in recent years that the natural agents derived from herbal medicines are beneficial for prevention/treatment of neurodegenerative diseases via regulation of mitochondrial dysfunction. Therefore, in this review, we will focus on the potential therapeutic agents from herbal medicines for treating neurodegenerative diseases via suppressing apoptosis through regulation of mitochondrial dysfunction, in order to provide a foundation for the development of more candidate drugs for neurodegenerative diseases from herbal medicine.

Therapeutic Mechanism and Key Alkaloids of Uncaria rhynchophylla in Alzheimer’s Disease From the Perspective of Pathophysiological Processes

Presently, there is a lack of effective disease-modifying drugs for the treatment of Alzheimer’s disease (AD). Uncaria rhynchophylla (UR) and its predominant active phytochemicals alkaloids have been studied to treat AD. This study used a novel network pharmacology strategy to identify UR alkaloids against AD from the perspective of AD pathophysiological processes and identified the key alkaloids for specific pathological process. The analysis identified 10 alkaloids from UR based on high-performance liquid chromatography (HPLC) that corresponded to 127 targets correlated with amyloid-β (Aβ) pathology, tau pathology and Alzheimer disease pathway. Based on the number of targets correlated with AD pathophysiological processes, angustoline, angustidine, corynoxine and isocorynoxeine are highly likely to become key phytochemicals in AD treatment. Among the 127 targets, JUN, STAT3, MAPK3, CCND1, MMP2, MAPK8, GSK3B, JAK3, LCK, CCR5, CDK5 and GRIN2B were identified as core targets. Based on the pathological process of AD, angustoline, angustidine and isocorynoxeine were identified as the key UR alkaloids regulating Aβ production and corynoxine, isocorynoxeine, dihydrocorynatheine, isorhynchophylline and hirsutine were identified as key alkaloids that regulate tau phosphorylation. The findings of this study contribute to a more comprehensive understanding of the key alkaloids and mechanisms of UR in the treatment of AD, as well as provide candidate compounds for drug research and development for specific AD pathological processes.

Comparison of the chemical constituents and anti-Alzheimer's disease effects of Uncaria rhynchophylla and Uncaria tomentosa

BACKGROUND

Uncaria tomentosa, which has similar chemical constituents with Uncaria rhynchophylla, has been reported to alleviate cognitive impairments in Alzheimer's disease (AD) animal models. This study aimed to compare the chemical constituents and anti-AD effect of the ethanol extracts of U. tomentosa (UTE) and U. rhynchophylla (URE).

METHODS

The high-performance liquid chromatography (HPLC) was used to compare the chemical constituents of UTE and URE. Streptozotocin (STZ) was intracerebroventricularly (ICV) injected into adult male Sprague-Dawley (SD) rats to establish AD model. UTE (400 mg/kg) or URE (400 mg/kg) was administrated intragastrically once daily to the rats for 6 consecutive weeks. Morris water maze (MWM) test was conducted to assess the neurological functions in the STZ-induced AD rats. The brain tissues of the rats were harvested for further biochemical assay.

RESULTS

The MWM test results showed both UTE and URE could significantly improve the learning and memory impairments induced by STZ in rats. Both UTE and URE could significantly inhibit the hyperphosphorylation of tau protein, reduce the elevated levels of pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α), enhance activities of antioxidant enzymes (SOD, CAT and GPx) and increase the protein expression of HO-1. In addition, UTE could decrease the malondialdehyde (MDA) level. Furthermore, both UTE and URE significantly enhanced Akt activation, down regulated the activation of glycogen synthase kinase 3β (GSK-3β), and induced the nuclear translocation of Nrf2 in the STZ-induced AD rats.

CONCLUSIONS

UTE and URE contained similar chemical constituents. We found for the first time that both of them could ameliorate cognitive deficits in the STZ-induced AD rats. The underlying molecular mechanism involve suppression of tau hyperphosphorylation, anti-oxidant and anti-neuroinflammation via modulating Akt (Ser473)/GSK3β (Ser9)-mediated Nrf2 activation. These findings amply implicate that both of UTE and URE are worthy of being developed clinically into pharmaceutical treatment for AD.

Recent Advances in the Anti-Inflammatory Activity of Plant-Derived Alkaloid Rhynchophylline in Neurological and Cardiovascular Diseases

Rhynchophylline (Rhy) is a plant-derived indole alkaloid isolated from Uncaria species. Both the plant and the alkaloid possess numerous protective properties such as anti-inflammatory, neuroprotective, anti-hypertensive, anti-rhythmic, and sedative effects. Several studies support the significance of the anti-inflammatory activity of the plant as an underlying mechanism for most of the pharmacological activities of the alkaloid. Rhy is effective in protecting both the central nervous system and cardiovascular system. Cerebro-cardiovascular disease primarily occurs due to changes in lifestyle habits. Many previous studies have highlighted the significance of Rhy in modulating calcium channels and potassium channels, thereby protecting the brain from neurodegenerative diseases and related effects. Rhy also has anticoagulation and anti-platelet aggregation activity. Although Rhy has displayed its role in protecting the cardiovascular system, very little is explored about its intervention in early atherosclerosis. Extensive studies are required to understand the cardioprotective effects of Rhye. This review summarized and discussed the various pharmacological effects of Rhy in neuro- and cardioprotection and in particular the relevance of Rhy in preventing early atherosclerosis using Rhy-loaded nanoparticles.

The Ameliorative Effects of Isorhynchophylline on Morphine Dependence Are Mediated Through the Microbiota-Gut-Brain Axis

Morphine abuse is a global public health problem. Increasing evidence has shown that gut microbiota dysbiosis plays an important role in several central nervous system diseases. However, whether there is an association between gut microbiota and morphine dependence remains unclear. In this study, the effects of isorhynchophylline on morphine dependence were evaluated based on the microbiota-gut-brain axis (MGBA). The results showed that isorhynchophylline could reverse the changes in alpha and beta diversity, composition, and richness of the intestinal flora occurring in morphine-dependent zebrafish, as well as the morphine-induced changes in the expression of MGBA-related genes in BV2 cells and the brain and intestine of zebrafish. Based on the results, we then used antibiotics to evaluate whether disrupting the gut microbiota would affect morphine addiction in zebrafish. The results showed that the antibiotic-induced intestinal floral imbalance changed the behavior of morphine-dependent zebrafish, the characteristics of the zebrafish intestinal flora, and the expression of MGBA-related genes in the zebrafish brain and intestine. Importantly, we also show that, following antibiotic administration, the ameliorative effects of isorhynchophylline on morphine addiction were lost. Together, our results indicate that the gut microbiota interacts with the brain, and dysbiosis of the intestinal flora may affect the efficacy of isorhynchophylline in the body. Our findings provide a novel framework for understanding the mechanisms of morphine addiction through the MGBA and may provide new therapeutic strategies for the use of Chinese medicines in the prevention of drug addiction.

Uncaria rhynchophylla and its Major Constituents on Central Nervous System: A Review on Their Pharmacological Actions

BACKGROUND

Uncaria rhynchophylla (Miq.) Jacks (Rubinaceae), a common herbal medicine known as Gou-teng in Chinese, is commonly used in Chinese medicine practice for the treatment of convulsions, hypertension, epilepsy, eclampsia and other cerebral diseases. The major active components of U. rhynchophylla are alkaloids, terpenoids and flavonoids. The protective effects of U. rhynchophylla and its major components on central nervous system (CNS) have become a focus of research in recent decades.

OBJECTIVE

The study aimed to systematically summarize the pharmacological activities of U. rhynchophylla and its major components on the CNS.

METHODS

This review summarized the experimental findings from our laboratories, together with other literature data obtained through a comprehensive search of databases including the Pubmed and the Web of Science.

RESULTS

U. rhynchophylla and its major components such as rhynchophylline and isorhynchophylline have been shown to have neuroprotective effects on Alzheimer's disease, Parkinson's disease, depression, cerebral ischaemia through a number of mechanisms including anti-oxidant, anti-inflammatory actions and regulation on neurotransmitters.

CONCLUSION

U. rhynchophylla and its major components have multiple beneficial pharmacological effects on CNS. Further studies on U. rhynchophylla and its major components are warranted to fully illustrate the underlying molecular mechanisms, pharmacokinetics, and toxicological profiles of these naturally occurring compounds and their potential for clinical application.

Recent research progress of Uncaria spp. based on alkaloids: phytochemistry, pharmacology and structural chemistry

Medicinal plants are well-known in affording clinically useful agents, with rich medicinal values by combining with disease targets through various mechanisms. Plant secondary metabolites as lead compounds lay the foundation for the discovery and development of new drugs in disease treatment. Genus Uncaria from Rubiaceae family is a significant plant source of active alkaloids, with anti-hypertensive, sedative, anti-Alzheimer's disease, anti-drug addiction and anti-inflammatory effects. This review summarizes and discuss the research progress of Uncaria based on alkaloids in the past 15 years, mainly in the past 5 years, including biosynthesis, phytochemistry, pharmacology and structural chemistry. Among, focusing on representative compounds rhynchophylline and isorhynchophylline, the pharmacological activities surrounding the central nervous system and cardiovascular system are described in detail. On the basis of case studies, this article provides a brief overview of the synthesis and analogues of representative compounds types. In summary, this review provides an early basis for further searching for new targets and activities, discussing the mechanisms of pharmacological activity and studying the structure-activity relationships of active molecules.

Effect of amyloid toxicity or chronic cerebral hypoperfusion on brain insulin resistance in a rat model with intracerebroventricular streptozotocin

Sporadic Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder affected by amyloid and vascular pathogenesis. Brain insulin resistance (BIR) has been suggested as one of the pathomechanisms of sporadic AD. We investigated how the amyloid and vascular pathogenesis of AD interacts with BIR. We examined experimental groups mimicking amyloid pathogenesis following intracerebroventriculr (icv) injection of amyloid β or vascular pathogenesis following permanent ligation of the bilateral common carotid arteries in Wistar rats that had undergone icv injection of streptozotocin. Behavioral tests and pathologic studies were performed. Cognitive impairments were induced by BIR superimposed by amyloid or vascular pathogenesis. Neuroinflammation in the white matter and hippocampus was aggravated by an interaction between BIR and vascular pathogenesis. Amyloid-associated pathology in the white matter was enhanced by BIR and vascular pathogenesis. Tau-associated pathology in the hippocampus was altered by BIR in a relation with amyloid or vascular pathogenesis. Our study may provide useful experimental insights based on an integrated approach to the influence of amyloid and vascular pathogenesis on BIR, permitting better understanding of the heterogeneous pathogenesis of sporadic AD. Pathologic responses in sporadic AD may differ depending on amyloid and vascular pathogenesis and may sometimes be synergistically aggravated when combined with BIR.

Evidence on Integrating Pharmacokinetics to Find Truly Therapeutic Agent for Alzheimer's Disease: Comparative Pharmacokinetics and Disposition Kinetics Profiles of Stereoisomers Isorhynchophylline and Rhynchophylline in Rats

Isorhynchophylline (IRN) and rhynchophylline (RN), a pair of stereoisomers, are tetracyclic oxindole alkaloids isolated from Uncaria rhynchophylla, a commonly used Chinese medicinal herb. These two compounds have drawn extensive attention due to their potent neuroprotective effects with promising therapeutic potential for the treatment of Alzheimer's disease (AD). However, IRN and RN can interconvert into each other in vivo after oral administration. The present study aimed to elucidate the pharmacokinetic profiles and disposition kinetics of the administered and generated stereoisomers in the brain and cerebrospinal fluid (CSF) after oral administration of equal dose of IRN or RN to rats. Our study demonstrated that after oral administration, RN showed significantly higher systemic exposure (6.5 folds of IRN, p < 0.001) and disposition in the brain (2.5 folds of IRN, p < 0.01) and CSF (3 folds of IRN, p < 0.001) than IRN. The results indicated that interconversion between IRN and RN occurred. Notably, regardless of the orally administered IRN or RN, RN would always be one of the major or predominant forms present in the body. Our results provided sound evidence supporting further development of RN as a potential therapeutic agent for the treatment of AD. Moreover, the present study sets a solid example that integrating pharmacokinetics is crucial to identify the truly therapeutic agent.

Antioxidant Activity and Neuroprotective Activity of Stilbenoids in Rat Primary Cortex Neurons via the PI3K/Akt Signalling Pathway

Antioxidant activity and neuroprotective activity of three stilbenoids, namely, trans-4-hydroxystilbene (THS), trans-3,5,4′-trihydroxy-stilbene (resveratrol, RES), and trans-3′,4′,3,5-tetrahydroxy-stilbene (piceatannol, PIC), against β-amyloid (Aβ)-induced neurotoxicity in rat primary cortex neurons were evaluated. THS, RES, and PIC significantly scavenged DPPH• and •OH radicals. All three stilbenoids were able to inhibit Aβ neurotoxicity by decreasing intracellular reactive oxygen species (ROS) via the PI3K/Akt signalling pathway. Specifically, stilbenoids significantly promoted Akt phosphorylation; suppressed Bcl-2/Bax expression; and inhibited caspase-9, caspase-3, and PARP cleavage. Molecular docking between stilbenoids with Akt indicated that stilbenoids could form hydrogen bond interactions with the COOH-terminal region of Akt. Additionally, the neuroprotective activity of stilbenoids correlated with the number and position of hydroxyl groups. The lack of meta-dihydroxyl groups on THS did not affect its neuroprotective activity in comparison with RES, whereas the ortho-dihydroxyl moiety on PIC significantly enhanced neuroprotective activity. These results provide new insights into the correlation between the biological activity and chemical structure of stilbenoids.

Isorhynchophylline alleviates learning and memory impairments induced by aluminum chloride in mice

BACKGROUND

To evaluate the effect of Isorhynchophylline (IRN) on the learning and memory impairments induced by aluminum chloride (AlCl3) in mice.

METHODS

Fifty male Balb-c mice (4-month-old) were randomly divided into five groups: control, AlCl3 plus vehicle, AlCl3 plus IRN (20 mg/kg), AlCl3 plus IRN (40 mg/kg) and AlCl3 plus donepezil (5 mg/kg). Learning and memory impairments were induced in mice by subcutaneously injecting with AlCl3 (50 mg/kg) once a day for 8 consecutive weeks. At the same time, mice were intragastrically given vehicle or IRN (20 and 40 mg/kg) or donepezil (5 mg/kg) 30 min before each AlCl3 injection. The spatial learning and memory function was assessed using radial arm maze. After sacrificed, the parameters of oxidative stress and cholinergic system in the brain tissues were examined with ELISA kits. Moreover, the expression of nuclear factor kappa B (NF-κB) signaling pathway was analyzed with western blotting.

RESULTS

The results showed that treatment with IRN could significantly ameliorate the cognitive deficits induced by AlCl3 in mice. In addition, treatment with IRN was found to reduce the level of malondialdehyde, enhance the activities of superoxide dismutases and catalase, increase the level of glutathione, and markedly inhibit the activity of acetylcholinesterase (AChE) in the brain tissues of the AlCl3-treated mice. Moreover, IRN significantly suppressed the phosphorylation of NF-κB p65 and IκBα in the brain tissues of AlCl3-treated mice. However, IRN did not show significant effect on the activity of butyrylcholinesterase.

CONCLUSION

Our findings demonstrated for the first time that IRN could alleviate learning and memory impairments induced by AlCl3 in mice. The neuroprotective effect of IRN against AlCl3-induced AD is probably mediated, at least in part, through inhibiting the AChE activity and reducing the oxidative damage of brain tissue via suppress the NF-κB signaling pathway. These results contributed to a better understanding of the in vivo anti-AD mechanism of IRN. It was concluded that IRN could protect the learning and memory function.

Isorhynchophylline, a Potent Plant Alkaloid, Induces Apoptotic and Anti-Metastatic Effects in Human Hepatocellular Carcinoma Cells through the Modulation of Diverse Cell Signaling Cascades

Isorhynchophylline (Rhy) is an active pharmacological component of Uncaria rhynchophylla that has been reported previously to exert significant antihypertensive and neuroprotective effects. However, very little is known about its potential anti-cancer activities. This study was carried out to evaluate the anticancer effects of Rhy against various human carcinoma cell lines. We found that Rhy exhibited substantial cytotoxic effect against human hepatocellular carcinoma HepG2 cells when compared with other human carcinoma cell lines including those of lung, pancreas, prostate, head and neck, breast, multiple myeloma, brain and renal cell carcinoma. Rhy induced apoptosis as characterized by accumulation of cells in sub G1 phase; positive Annexin V binding; activation of caspase-8, -9, and -3; and cleavage of PARP (poly-ADP ribose polymerase). This effect of Rhy correlated with the down-regulation of various proteins that mediated cell proliferation, cell survival, metastasis, and angiogenesis. Moreover, cell proliferation, migration, and constitutive CXCR4 (C-X-C chemokine receptor type 4), MMP-9 (Matrix metallopeptidase-9), and MMP-2 expression were inhibited upon Rhy treatment. We further investigated the effect of Rhy on the oncogenic cell signaling cascades through phospho-kinase array profiling assay. Rhy was found to abrogate phospho-p38, ERK, JNK, CREB, c-Jun, Akt, and STAT3 signals, but interestingly enhanced phospho-p53 signal. Overall, our results indicate, for the first time, that Rhy could exert anticancer and anti-metastatic effects through regulation of multiple signaling cascades in hepatocellular carcinoma cells.

Natural products against Alzheimer's disease: Pharmaco-therapeutics and biotechnological interventions

Alzheimer's disease (AD) is a severe, chronic and progressive neurodegenerative disease associated with memory and cognition impairment ultimately leading to death. It is the commonest reason of dementia in elderly populations mostly affecting beyond the age of 65. The pathogenesis is indicated by accumulation of the amyloid-beta (Aβ) plaques and neurofibrillary tangles (NFT) in brain tissues and hyperphosphorylation of tau protein in neurons. The main cause is considered to be the formation of reactive oxygen species (ROS) due to oxidative stress. The current treatment provides only symptomatic relief by offering temporary palliative therapy which declines the rate of cognitive impairment associated with AD. Inhibition of the enzyme acetylcholinesterase (AChE) is considered as one of the major therapeutic strategies offering only symptomatic relief and moderate disease-modifying effect. Other non-cholinergic therapeutic approaches include antioxidant and vitamin therapy, stem cell therapy, hormonal therapy, use of antihypertensive or lipid-lowering medications and selective phosphodiesterase (PDE) inhibitors, inhibition of β-secretase and γ-secretase and Aβ aggregation, inhibition of tau hyperphosphorylation and intracellular NFT, use of nonsteroidal anti-inflammatory drugs (NSAIDs), transition metal chelators, insulin resistance drugs, etanercept, brain-derived neurotrophic factor (BDNF) etc. Medicinal plants have been reported for possible anti-AD activity in a number of preclinical and clinical trials. Ethnobotany, being popular in China and in the Far East and possibly less emphasized in Europe, plays a substantial role in the discovery of anti-AD agents from botanicals. Chinese Material Medica (CMM) involving Chinese medicinal plants has been used traditionally in China in the treatment of AD. Ayurveda has already provided numerous lead compounds in drug discovery and many of these are also undergoing clinical investigations. A number of medicinal plants either in their crude forms or as isolated compounds have exhibited to reduce the pathological features associated with AD. In this present review, an attempt has been made to elucidate the molecular mode of action of various plant extracts, phytochemicals and traditional herbal formulations investigated against AD as reported in various preclinical and clinical tests. Herbal synergism often found in polyherbal formulations were found effective to combat disease heterogeneity as found in complex pathogenesis of AD. Finally a note has been added to describe biotechnological improvement, genetic and genomic resources and mathematical and statistical techniques for empirical model building associated with anti-AD plant secondary metabolites and their source botanicals.

Epigenetics changes caused by the fusion of human embryonic stem cell and ovarian cancer cells

To observe the effect of gene expression and tumorigenicity in hybrid cells of human embryonic stem cells (hESCs) and ovarian cancer cells in vitro and in vivo using a mouse model, and to determine its feasibility in reprogramming tumour cells growth and apoptosis, for a potential exploration of the role of hESCs and tumour cells fusion in the management of ovarian cancer. Stable transgenic hESCs (H1) and ovarian cancer cell line OVCAR-3 were established before fusion, and cell fusion system was established to analyse the related indicators. PTEN expression in HO-H1 cells was higher than those in the parental stem cells and lower than those in parental tumour cells; the growth of OV-H1 (RFP+GFP) hybrid cells with double fluorescence expressions were obviously slower than that of human embryonic stem cells and OVCAR-3 ovarian cancer cells. The apoptosis signal of the OV-H1 hybrid cells was significantly higher than that of the hESCs and OVCAR-3 ovarian cancer cells. In vivo results showed that compared with 7 days, 28 days and 35 days after inoculation of OV-H1 hybrid cells; also, apoptotic cell detection indicated that much stronger apoptotic signal was found in OV-H1 hybrid cells inoculated mouse. The hESCs can inhibit the growth of OVCAR-3 cells in vitro by suppressing p53 and PTEN expression to suppress the growth of tumour that may be achieved by inducing apoptosis of OVCAR-3 cells. The change of epigenetics after fusion of ovarian cancer cells and hESCs may become a novel direction for treatment of ovarian cancer.

The Role of 6-Gingerol on Inhibiting Amyloid β Protein-Induced Apoptosis in PC12 Cells

Our previous study suggests that ginger root extract can reverse behavioral dysfunction and prevent Alzheimer's disease (AD)-like symptoms induced by the amyloid-β protein (Aβ) in a rat model. 6-Gingerol is the major gingerol in ginger rhizomes, but its effect on the treatment of AD remains unclear. In this study, we aimed to determine if 6-gingerol had a protective effect on Aβ1-42-induced damage and apoptotic death in rat pheochromocytoma cells (PC12 cells) and to investigate the underlying mechanisms by which 6-gingerol may exert its neuroprotective effects. Our results indicated that pre-treatment with 6-gingerol significantly increased cell viability and reduced cell apoptosis in Aβ1-42-treated cells. Moreover, 6-gingerol pretreatment markedly reduced the level of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA), the production of nitric oxide (NO), and the leakage of lactate dehydrogenase (LDH) and increased superoxide dismutase (SOD) activity compared with the Aβ1-42 treatment group. In addition, 6-gingerol pretreatment also significantly enhanced the protein levels of phosphorylated Akt (p-Akt) and glycogen synthase kinase-3β (p-GSK-3β). Overall, these results indicate that 6-gingerol exhibited protective effects on apoptosis induced by Aβ1-42 in cultured PC12 cells by reducing oxidative stress and inflammatory responses, suppressing the activation of GSK-3β and enhancing the activation of Akt, thereby exerting neuroprotective effects. Therefore, 6-gingerol may be useful in the prevention and/or treatment of AD.

Plant alkaloids as drug leads for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative illness associated with dementia and is most prevalent among the elderly population. Current medications can only treat symptoms. Alkaloids are structurally diverse and have been an important source of therapeutics for various brain disorders. Two US Food and Drug Administration (FDA)-approved acetylcholinesterase inhibitors for AD, galantamine and rivastigmine, are in fact alkaloids. In addition, clinical trials of four other extensively studied alkaloids-huperzine A, caffeine, nicotine, and indomethacin-have been conducted but do not convincingly demonstrate their clinical efficacy for AD. Interestingly, rhynchophylline, a known neuroprotective alkaloid, was recently discovered by in silico screening as an inhibitor of EphA4, a novel target for AD. Here, we review the pathophysiological mechanisms underlying AD, current treatment strategies, and therapeutic potential of several selected plant alkaloids in AD, highlighting their various drug targets and the key supportive preclinical and clinical studies. Future research should include more rigorous clinical studies of the most promising alkaloids, the further development of recently discovered candidate alkaloids, and the continual search for new alkaloids for relevant drug targets. It remains promising that an alkaloid drug candidate could significantly affect the progression of AD in addition to providing symptomatic relief.

Design, synthesis and biological evaluation of novel potent MDM2/p53 small-molecule inhibitors

Regioselective synthesis, biological evaluation and 3D-molecular modeling for a series of novel diastereomeric 2-thioxo-5H-dispiro[imidazolidine-4,3-pyrrolidine-2,3-indole]-2,5(1H)-diones are described. The studied compounds have been tentatively identified as potent small molecule MDM2/p53 PPI inhibitors and can therefore be reasonably regarded as promising anticancer therapeutics.

Isorhynchophylline improves learning and memory impairments induced by D-galactose in mice

Isorhynchophylline (IRN), an alkaloid isolated from Uncaria rhynchophylla, has been reported to improve cognitive impairment induced by beta-amyloid in rats. However, whether IRN could also ameliorate the D-galactose (D-gal)-induced mouse memory deficits is still not clear. In the present study, we aimed to investigate whether IRN had potential protective effect against the D-gal-induced cognitive deficits in mice. Mice were given a subcutaneous injection of D-gal (100mg/kg) and orally administered IRN (20 or 40mg/kg) daily for 8weeks, followed by assessing spatial learning and memory function by the Morris water maze test. The results showed that IRN significantly improved spatial learning and memory function in the D-gal-treated mice. In the mechanistic studies, IRN significantly increased the level of glutathione (GSH) and the activities of superoxide dismutase (SOD) and catalase (CAT), while decreased the level of malondialdehyde (MDA) in the brain tissues of the D-gal-treated mice. Moreover, IRN (20 or 40mg/kg) significantly inhibited the production of prostaglandin E 2 (PGE2) and nitric oxide (NO), and the mRNA expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), as well as the activation of nuclear factor kappa B (NF-κB) in the brain tissues of D-gal-treated mice. Our results amply demonstrated that IRN was able to ameliorate cognitive deficits induced by D-gal in mice, and the observed cognition-improving action may be mediated, at least in part, through enhancing the antioxidant status and anti-inflammatory effect of brain tissues via NFκB signaling.

Isorhynchophylline protects against pulmonary arterial hypertension and suppresses PASMCs proliferation

Increased pulmonary arterial smooth muscle cells (PASMCs) proliferation is a key pathophysiological component of pulmonary vascular remodeling in pulmonary arterial hypertension (PAH). Isorhynchophylline (IRN) is a tetracyclic oxindole alkaloid isolated from the Chinese herbal medicine Uncaria rhynchophylla. It has long been used clinically for treatment of cardiovascular and cerebrovascular diseases. However, very little is known about whether IRN can influence the development of PAH. Here we examined the effect of IRN on monocrotaline (MCT) induced PAH in rats. Our data demonstrated that IRN prevented MCT induced PAH in rats, as assessed by right ventricular (RV) pressure, the weight ratio of RV to (left ventricular+septum) and RV hypertrophy. IRN significantly attenuated the percentage of fully muscularized small arterioles, the medial wall thickness, and the expression of smooth muscle α-actin (α-SMA) and proliferating cell nuclear antigen (PCNA). In vitro studies, IRN concentration-dependently inhibited the platelet-derived growth factor (PDGF)-BB-induced proliferation of PASMCs. Fluorescence-activated cell-sorting analysis showed that IRN caused G0/G1 phase cell cycle arrest. IRN-induced growth inhibition was associated with downregulation of Cyclin D1 and CDK6 as well as an increase in p27Kip1 levels in PDGF-BB-stimulated PASMCs. Moreover, IRN negatively modulated PDGF-BB-induced phosphorylation of PDGF-Rβ, ERK1/2, Akt/GSK3β, and signal transducers and activators of transcription 3 (STAT3). These results demonstrate that IRN could inhibit PASMCs proliferation and attenuate pulmonary vascular remodeling after MCT induction. These beneficial effects were at least through the inhibition of PDGF-Rβ phosphorylation and its downstream signaling pathways. Therefore, IRN might be a potential candidate for the treatment of PAH.