Toki-to protects dopaminergic neurons in the substantia nigra from neurotoxicity of MPTP in mice

DNA Microarray-Based Screening and Characterization of Traditional Chinese Medicine

The application of DNA microarray assay (DMA) has entered a new era owing to recent innovations in omics technologies. This review summarizes recent applications of DMA-based gene expression profiling by focusing on the screening and characterizationof traditional Chinese medicine. First, herbs, mushrooms, and dietary plants analyzed by DMA along with their effective components and their biological/physiological effects are summarized and discussed by examining their comprehensive list and a list of representative effective chemicals. Second, the mechanisms of action of traditional Chinese medicine are summarized by examining the genes and pathways responsible for the action, the cell functions involved in the action, and the activities found by DMA (silent estrogens). Third, applications of DMA for traditional Chinese medicine are discussed by examining reported examples and new protocols for its use in quality control. Further innovations in the signaling pathway based evaluation of beneficial effects and the assessment of potential risks of traditional Chinese medicine are expected, just as are observed in other closely related fields, such as the therapeutic, environmental, nutritional, and pharmacological fields.

A Potential Alternative against Neurodegenerative Diseases: Phytodrugs

Neurodegenerative diseases (ND) primarily affect the neurons in the human brain secondary to oxidative stress and neuroinflammation. ND are more common and have a disproportionate impact on countries with longer life expectancies and represent the fourth highest source of overall disease burden in the high-income countries. A large majority of the medicinal plant compounds, such as polyphenols, alkaloids, and terpenes, have therapeutic properties. Polyphenols are the most common active compounds in herbs and vegetables consumed by man. The biological bioactivity of polyphenols against neurodegeneration is mainly due to its antioxidant, anti-inflammatory, and antiamyloidogenic effects. Multiple scientific studies support the use of herbal medicine in the treatment of ND; however, relevant aspects are still pending to explore such as metabolic analysis, pharmacokinetics, and brain bioavailability.

Plant-Derived Natural Products for Parkinson's Disease Therapy

Plant-derived natural products have made their own niche in the treatment of neurological diseases since time immemorial. Parkinson's disease (PD), the second most prevalent neurodegenerative disorder, has no cure and the treatment available currently is symptomatic. This chapter thoughtfully and objectively assesses the scientific basis that supports the increasing use of these plant-derived natural products for the treatment of this chronic and progressive disorder. Proper considerations are made on the chemical nature, sources, preclinical tests and their validity, and mechanisms of behavioural or biochemical recovery observed following treatment with various plants derived natural products relevant to PD therapy. The scientific basis underlying the neuroprotective effect of 6 Ayurvedic herbs/formulations, 12 Chinese medicinal herbs/formulations, 33 other plants, and 5 plant-derived molecules have been judiciously examined emphasizing behavioral, cellular, or biochemical aspects of neuroprotection observed in the cellular or animal models of the disease. The molecular mechanisms triggered by these natural products to promote cell survivability and to reduce the risk of cellular degeneration have also been brought to light in this study. The study helped to reveal certain limitations in the scenario: lack of preclinical studies in all cases barring two; heavy dependence on in vitro test systems; singular animal or cellular model to establish any therapeutic potential of drugs. This strongly warrants further studies so as to reproduce and confirm these reported effects. However, the current literature offers scientific credence to traditionally used plant-derived natural products for the treatment of PD.

Dangguijakyak-San Protects against 1-Methyl-4-phenyl-1,2,3,6,-tetrahydropyridine-Induced Neuronal Damage via Anti-Inflammatory Action

Dangguijakyak-san (DJS), a famous traditional Korean multiherbal medicine, has been used to treat gynecological and neuro-associated disease. Recent studies demonstrated that DJS has multiple bioactivities including neuroprotection. In the present study, we were to investigate the effect of DJS and its mechanism in an in vitro and in vivo model of Parkinson's disease (PD). In primary mesencephalic culture system, DJS attenuated the dopaminergic cell damage induced by 1-methyl-4-phenylpyridine toxicity, and it inhibited production of inflammatory factors such as tumor necrosis factor α (TNF- α ), nitric oxide (NO), and activation of microglial cells. Then, we confirmed the effect of DJS in a mouse PD model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In the pole test, DJS at 50 mg/kg/day for 5 days showed increase of motor activity showing shortened time to turn and locomotor activity compared with the MPTP only treated mice. In addition, DJS significantly protected nigrostriatal dopaminergic neuron from MPTP stress. Moreover, DJS showed inhibition of gliosis in the substantia nigra pars compacta. These results have therapeutic implications for DJS in the treatment of PD via anti-inflammatory effects.

Omic techniques in systems biology approaches to traditional Chinese medicine research: present and future

Omic techniques have become key tools in the development of systems biology. As the holistic approaches underlying the practice of traditional Chinese medicine (TCM) and new tendencies in Western medicine towards personalised medicine require in-depth knowledge of mechanisms of action and active compounds, the use of omic techniques is crucial for understanding and interpretation of TCM development, especially in view of its expansion in Western countries. In this short review, omic applications in TCM research are reviewed which has allowed some speculation regarding future perspectives for these approaches in TCM modernisation and standardisation. Guidelines for good practice for the application of omics in TCM research are also proposed.

Anti-Parkinsonian drug discovery from herbal medicines: what have we got from neurotoxic models?

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal medicines are used to treat Parkinson's disease (PD) in ancient medical systems in Asian countries such as India, China, Japan and Korea based on their own anecdotal or experience-based theories.

AIM OF THE REVIEW

To systematically summarize and analyze the anti-Parkinsonian activities of herbal preparations (including active compounds, herbal extracts and formulations) investigated in the neurotoxic models of PD and provide future references for basic and clinical investigations.

MATERIALS AND METHODS

All the herbal materials tested on in vitro and in vivo neurotoxic models of PD were retrieved from PubMed database by using pre-set searching strings. The relevant compounds and herbal extracts with anti-Parkinsonian activities were included and analyzed according to their chemical classifications or biological activities.

RESULTS

A total of 51 herbal medicines were analyzed. A diversity of compounds isolated from herbal materials were reported to be effective on neurotoxic models of PD by modulating multiple key events or signaling pathways implicated in the pathogenesis of PD. The main structure types of these compounds belong to catechols, stilbenoids, flavonoids, phenylpropanoids and lignans, phenylethanoid glycosides and terpenes. Although some herbal extracts and formulations have shown positive results on PD animal models, the relative compounds accounting for the effects and the underlying mechanisms remain to be further investigated.

CONCLUSIONS

Herbal medicines can be an alternative and valuable source for anti-Parkinsonian drug discovery. Compounds classified into stilbenoids, flavonoids, catechols and terpenes may be the most promising candidates for further investigation. Some well-studies compounds such as baicalein, puerarin, resveratrol, curcumin and ginsenosides deserve further consideration in clinical trials. In-depth experimental studies are still needed to evaluate the efficacy of herbal extracts and formulations in PD models.

Dangguijakyak-san, a medicinal herbal formula, protects dopaminergic neurons from 6-hydroxydopamine-induced neurotoxicity

AIM OF THE STUDY

Dangguijakyak-san (DJS) is a multi-herbal formula that has long been widely used in traditional Oriental medicine to treat gynecologic disorders, including neurological symptoms. Recent clinical and experimental studies have reported aging and anti-neurodegenerative effects of DJS. In this study, we evaluated the neuroprotective effects of DJS on dopaminergic (DA) neurons damaged by 6-hydroxydopamine (6-OHDA).

MATERIALS AND METHODS

To evaluate the protective effects of DJS, we analyzed viability in SH-SY5Y neuroblastoma cells and tyrosine hydroxylase (TH) staining in primary DA cells. To explore the possible mechanism(s) of neuroprotection, we assessed anti-oxidant activity by measuring reactive oxygen species (ROS) and glutathione (GSH) levels. To determine mitochondria-mediated apoptotic activity, we examined mitochondrial membrane potential, cytochrome c release, and caspase-3 activation.

RESULTS

DJS at 0.05-5 μg/mL significantly protected SH-SY5Y cells from 6-OHDA toxicity, dose-dependently, and attenuated 6-OHDA damage in primary DA cells. DJS reduced 6-OHDA-induced intracellular ROS production and GSH depletion and inhibited mitochondrial membrane instability, cytosolic cytochrome c release, and caspase-3 activation.

CONCLUSIONS

These results demonstrate that DJS has neuroprotective effects in DA neurons against 6-OHDA-induced toxicity through anti-oxidant and anti-mitochondrial-mediated apoptotic activities.

Significance of SGK1 in the regulation of neuronal function

The present brief review highlights the putative role of the serum- and glucocorticoid-inducible-kinase-1 (SGK1) in the regulation of neuronal function. SGK1 is genomically upregulated by cell shrinkage and by a variety of hormones including mineralocorticoids and glucocorticoids. The kinase is activated by insulin and growth factors via phosphatidylinositide-3-kinase (PI3-kinase), phosphoinositide-dependent kinase PDK1 and mammalian target of rapamycin mTORC2. SGK1 upregulates ion channels (e.g. SCN5A, ENaC, ASIC1, TRPV5,6, ROMK, Kv1.1-5, KCNEx/KCNQ1-5, GluR6, VSOAC, ClC2, CFTR), carriers (e.g. NHE3, NKCC2, NCC, NaPiIIb, SMIT, GLUT1,4, SGLT1, NaDC, EAAT1-5, SN1, ASCT2, 4F2/LAT, PepT2), and the Na(+)/K(+)-ATPase. SGK1 regulates enzymes (e.g. glycogen-synthase-kinase-3, ubiquitin-ligase Nedd4-2, phosphomannose-mutase-2), and transcription factors (e.g. forkhead transcription factor Foxo3a, β-catenin, nuclear factor-kappa-B (NFB)). SGK1 participates in the regulation of transport, hormone release, neuroexcitability, inflammation, coagulation, cell proliferation and apoptosis. SGK1 contributes to regulation of renal Na(+) retention, renal K(+) elimination, salt appetite, gastric acid secretion, intestinal Na(+)/H(+) exchange and nutrient transport, insulin-dependent salt sensitivity of blood pressure, salt sensitivity of peripheral glucose uptake, cardiac repolarization and memory consolidation. Presumably, SGK1 contributes to the regulation of diverse cerebral functions (e.g. memory consolidation, fear retention) and the pathophysiology of several cerebral diseases (e.g. Parkinson's disease, schizophrenia, depression, Alzheimer's disease). Despite multiple SGK1 functions, the phenotype of the SGK1 knockout mouse is mild and becomes only apparent under challenging conditions.

Preventive role of PD-1 on MPTP-induced dopamine depletion in mice

Many current studies of Parkinson's disease (PD) suggest that inflammation is involved in the neurodegenerative process. PD-1, a traditional Korean medicine, used to treat various brain diseases in Korea. This study was designed to investigate the effect of PD-1 extract in the Parkinson's model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) lesioned mice. The MPTP administration caused the dopamine neuron loss in the striatum and substantia nigra pars compacta (SNpc), which was demonstrated by a depletion of tyrosine hydroxylase (TH). In addition, a reduction of bcl-2 expression with elevation of bax expression, caspase-3 activation, and release of cytochrome c into cytosol in dopaminergic neurons of SNpc were noted. Oral administration of PD-1 extract (50 and 100 mg kg(-1)) attenuated the MPTP-induced depletion of TH proteins in the striatum and SNpc and prevented the apoptotic effects. These results indicate that PD-1 extract is able to protect dopaminergic neurons from MPTP-induced neuronal death, with important implications for the treatment of PD.

Toxicogenomics: transcription profiling for toxicology assessment

Toxicogenomics, the application of transcription profiling to toxicology, has been widely used for elucidating the molecular and cellular actions of chemicals and other environmental stressors on biological systems, predicting toxicity before any functional damages, and classification of known or new toxicants based on signatures of gene expression. The success of a toxicogenomics study depends upon close collaboration among experts in different fields, including a toxicologist or biologist, a bioinformatician, statistician, physician and, sometimes, mathematician. This review is focused on toxicogenomics studies, including transcription profiling technology, experimental design, significant gene extraction, toxicological results interpretation, potential pathway identification, database input and the applications of toxicogenomics in various fields of toxicological study.