Catalpol protects mesencephalic neurons against MPTP induced neurotoxicity via attenuation of mitochondrial dysfunction and MAO-B activity

Real-world Chinese herbal medicine for Parkinson's disease: a hospital-based retrospective analysis of electronic medical records

Background

Parkinson's disease (PD) is a progressive neurodegenerative condition. Chinese medicine therapies have demonstrated effectiveness for PD in controlled settings. However, the utilization of Chinese medicine therapies for PD in real-world clinical practice and the characteristics of patients seeking these therapies have not been thoroughly summarized.

Method

The study retrospectively analyzed initial patient encounters (PEs) with a first-listed diagnosis of PD, based on electronic medical records from Guangdong Provincial Hospital of Chinese Medicine between July 2018 and July 2023.

Results

A total of 3,206 PEs, each corresponding to an individual patient, were eligible for analyses. Approximately 60% of patients made initial visits to the Chinese medicine hospital after receiving a PD diagnosis, around 4.59 years after the onset of motor symptoms. Over 75% of the patients visited the Internal Medicine Outpatient Clinic at their initial visits, while a mere 13.85% visited PD Chronic Care Clinic. Rest tremor (61.98%) and bradykinesia (52.34%) are the most commonly reported motor symptoms, followed by rigidity (40.70%). The most commonly recorded non-motor symptoms included constipation (31.88%) and sleep disturbance (25.27%). Integration of Chinese medicine and conventional medicine therapies was the most common treatment method (39.15%), followed by single use of Chinese herbal medicine (27.14%). The most frequently prescribed herbs for PD included Glycyrrhiza uralensis Fisch. (gan cao), Astragalus mongholicus Bunge (huang qi), Atractylodes macrocephala Koidz. (bai zhu), Angelica sinensis (Oliv.) Diels (dang gui), Rehmannia glutinosa (Gaertn.) DC. (di huang), Paeonia lactiflora Pall. (bai shao), Bupleurum chinense DC. (chai hu), Citrus aurantium L. (zhi qiao/zhi shi/chen pi), Panax ginseng C. A. Mey. (ren shen), and Poria cocos (Schw.) Wolf (fu ling). These herbs contribute to formulation of Bu zhong yi qi tang (BZYQT).

Conclusion

Patients typically initiated Chinese medical care after the establishment of PD diagnosis, ~4.59 years post-onset of motor symptoms. The prevalent utilization of CHM decoctions and patented Chinese herbal medicine products, underscores its potential in addressing both motor and non-motor symptoms. Despite available evidence, rigorous clinical trials are needed to validate and optimize the integration of CHM, particularly BZYQT, into therapeutic strategies for PD.

Effects of Catalpol on Alzheimer's Disease and Its Mechanisms

Alzheimer's disease (AD) is a degenerative disease of the central nervous system characterized by memory loss and cognitive dysfunction. With the increasing aging of the population, the incidence of AD and the number of patients are also increasing year by year, causing more and more heavy burdens to the family and society. Catalpol, an iridoid glycoside compound, is one of the main active components of Rehmannia glutinosa. At present, a large number of experimental studies in vivo and in vitro have confirmed that catalpol has antioxidant, anti-inflammatory, antiapoptotic, and other neuroprotective effects, and it plays a significant role in the prevention and treatment of AD, with very small side effects and high safety. Therefore, it may be an ideal drug for the treatment of AD. Based on this, the role and mechanism of catalpol in AD will be comprehensively reviewed in the following.

The pathogenesis and treatment mechanism of Parkinson's disease from the perspective of traditional Chinese medicine

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disease with no treatment currently available to modify its progression. Traditional Chinese medicine (TCM) has gained attention for its unique theoretical basis and clinical effects. Many studies have reported on the clinical effects and pharmacological mechanisms of Chinese herbs in PD. However, few studies have focused on the treatment mechanisms of anti-PD TCM drugs from the perspective of TCM itself.

PURPOSE

To elaborate the treatment mechanisms of anti-PD TCM drugs in the perspective of TCM.

METHODS

We performed a literature survey using traditional books of Chinese medicine and online scientific databases including PubMed, Web of Science, Google Scholar, China National Knowledge Infrastructure (CNKI), and others up to July 2021.

RESULTS

TCM theory states that PD is caused by a dysfunction of the zang-fu organs (liver, spleen, kidney, and lung) and subsequent pathogenic factors (wind, fire, phlegm, and blood stasis). Based on the pathogenesis, removing pathogenic factors and restoring visceral function are two primary treatment principles for PD in TCM. The former includes dispelling wind, clearing heat, resolving phlegm, and promoting blood circulation, while the latter involves nourishing the liver and kidney and strengthening the spleen. The anti-PD mechanisms of the active ingredients of TCM compounds and herbs at different levels include anti-apoptosis, anti-inflammation, and anti-oxidative stress, as well as the restoration of mitochondrial function and the regulation of autophagy and neurotransmitters.

CONCLUSION

Chinese herbs and prescriptions can be used to treat PD by targeting multiple pharmacological mechanisms.

A systematic review on botany, processing, application, phytochemistry and pharmacological action of Radix Rehmnniae

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Rehmanniae (RR) is the tuber root of Rehmannia glutionsa Libosch, which was firstly recorded in Shennong's Classic of Materia Medica (⟪⟫). RR is a non-toxic and wide used traditional Chinese medicine. RR has the effect of clearing heat, generating essence, cooling blood, stopping bleeding, nourishing yin and blood, and filling marrow. It is used in clinic in the form of processed decoction pieces, including Dry Radix Rehmnniae (DRR) and Rehmanniae Radix Praeparata (RRP). The application of RR in traditional Chinese medicine (TCM) prescriptions can treat various diseases, such as anemia, irregular menstruation, deficiency of liver yin, renal failure and so on.

AIM OF REVIEW

This paper aims to provide a comprehensive and productive review of RR, which mainly contains botanical characteristics, processing methods, traditional application, chemical composition, quality control and pharmacological action.

MATERIALS AND METHODS

Literature search was conducted through the Web of Science, Baidu Scholar, ScienceDirect, PubMed, CNKI, and WanFang DATA using the keywords "Radix Rehmnniae", "Rehmanniae Radix Praeparata", "processing", "clinical application", "chemical composition", "quality control", and "pharmacological action". In addition, information was collected from relevant textbooks, reviews, and documents.

RESULTS

RR is a traditional Chinese herbal medicine with clinical value and rich resources. More than 100 components have been isolated and identified from RR. It has multiple pharmacological actions, such as hemostasis, antioxidation, anti-osteoporosis, lowering blood sugar, improving renal function, anti-inflammation, protecting neuronal function, antidepression and anti-anxiety. DRR and RRP are two different processed products of RR. After processing, there are great changes in property, taste, efficacy, clinical application, chemical composition and pharmacological action. At present, identifying chemical constituents of RR and its medicinal value has been deeply studied. However, there is a lack of research on the reasons for the differences in pharmacological effects between DRR and RRP. The reasons for these differences need to be further verified. Catalpol, the active component of RR, has been studied extensively in the literature, but the pharmacological effects of catalpol cannot represent the pharmacological effects of the whole RR. In the future, effective components such as rehmannioside D, polysaccharide, total glycosides, and effective parts in RR need to be further studied and developed. The pharmacodynamic material basis and mechanism of RR need to be further discussed. The scientific connotation and processing methods of RRP need to be studied and standardized.

De novo genome assembly of the potent medicinal plant Rehmannia glutinosa using nanopore technology

Rehmannia glutinosa is a potent medicinal plant with a significant importance in traditional Chinese medicine. Its root is enriched with various bioactive molecules mainly iridoids, possessing important pharmaceutical properties. However, the molecular biology and evolution of R. glutinosa have been largely unexplored. Here, we report a reference genome of R. glutinosa using Nanopore technology, Illumina and Hi-C sequencing. The assembly genome is 2.49 Gb long with a scaffold N50 length of 70 Mb and high heterozygosity (2%). Since R. glutinosa is an autotetraploid (4n = 56), the difference between each set of chromosomes is very small, and it is difficult to distinguish the two sets of chromosomes using Hi-C. Hence, only one set of the genome size was mounted to the chromosome level. Scaffolds covering 52.61% of the assembled genome were anchored on 14 pseudochromosomes. Over 67% of the genome consists of repetitive sequences dominated by Copia long terminal repeats and 48,475 protein-coding genes were predicted. Phylogenetic analysis corroborates the placement of R. glutinosa in the Orobanchaceae family. Our results indicated an independent and very recent whole genome duplication event that occurred 3.64 million year ago in the R. glutinosa lineage. Comparative genomics analysis demonstrated expansion of the UDP-dependent glycosyltransferases and terpene synthase gene families, known to be involved in terpenoid biosynthesis and diversification. Furthermore, the molecular biosynthetic pathway of iridoids has been clarified in this work. Collectively, the generated reference genome of R. glutinosa will facilitate discovery and development of important pharmacological compounds.

Catalpol counteracts the pathology in a mouse model of Duchenne muscular dystrophy by inhibiting the TGF-β1/TAK1 signaling pathway

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease caused by a mutation in the gene encoding the dystrophin protein. Catalpol is an iridoid glycoside found in Chinese herbs with anti-inflammatory, anti-oxidant, anti-apoptotic, and hypoglycemic activities that can protect against muscle wasting. In the present study we investigated the effects of catalpol on DMD. Aged Dystrophin-deficient (mdx) mice (12 months old) were treated with catalpol (100, 200 mg·kg-1·d-1, ig) for 6 weeks. At the end of the experiment, the mice were sacrificed, and gastrocnemius (GAS), tibialis anterior (TA), extensor digitorum longus (EDL), soleus (SOL) muscles were collected. We found that catalpol administration dose-dependently increased stride length and decreased stride width in Gait test. Wire grip test showed that the time of wire grip and grip strength were increased. We found that catalpol administration dose-dependently alleviated skeletal muscle damage, evidenced by reduced plasma CK and LDH activity as well as increased the weight of skeletal muscles. Catalpol administration had no effect on dystrophin expression, but exerted anti-inflammatory effects. Furthermore, catalpol administration dose-dependently decreased tibialis anterior (TA) muscle fibrosis, and inhibited the expression of TGF-β1, TAK1 and α-SMA. In primary myoblasts from mdx mice, knockdown of TAK1 abolished the inhibitory effects of catalpol on the expression levels of TGF-β1 and α-SMA. In conclusion, catalpol can restore skeletal muscle strength and alleviate skeletal muscle damage in aged mdx mice, thus may provide a novel therapy for DMD. Catalpol attenuates muscle fibrosis by inhibiting the TGF-β1/TAK1 signaling pathway.

Therapeutic potential of catalpol and geniposide in Alzheimer's and Parkinson's diseases: A snapshot of their underlying mechanisms

Rehmannia glutinosa, the fresh or dried root of Rehmannia glutinosa (Gaertn.) Libosch. ex Fisch. & Mey., and Gardenia, the fruit of Gardenia jasminoides Ellis from Rubiaceae, both are famous traditional Chinese medicines that have been traditionally used in China. Catalpol and geniposide, as two kinds of iridoid glycosides with high activities, are the main bioactive components in Rehmannia glutinosa and Gardenia jasminoides Ellis, respectively. Over the past few decades, catalpol and geniposide have been widely studied for their therapeutic effects. The preclinical experiments demonstrated that they possessed significant neuroprotective activities against Alzheimer's disease, Parkinson's disease, stroke, and depression, etc. In this paper, the pharmacological effects and mechanisms of catalpol and geniposide on Alzheimer's disease and Parkinson's disease from 2005 to now were systematically summarized and comprehensively analyzed. At the same time, the pharmacokinetic characteristics of the analyzed compounds were also described, hoping to provide some enlightenment for the design, research, and development of iridoid glycosides.

Caffeic acid protects mice pancreatic islets from oxidative stress induced by multi-walled carbon nanotubes (MWCNTs)

Increasing applications of carbon nanotubes (CNTs) indicate the necessity to examine their toxicity. According to previous studies, CNTs caused oxidative stress that impaired β-cell functions and reduced insulin secretion. Our previous study indicated that single-walled carbon nanotubes (SWCNTs) could induce oxidative stress in pancreatic islets. However, there is no study on the effects of multi-walled carbon nanotubes (MWCNTs) on islets and β-cells. Therefore, the present study aims to evaluate effects of MWCNTs on the oxidative stress of islets and the protective effects of caffeic acid (CA) as an antioxidant. The effects of MWCNTs and CA on islets were investigated using MTT assay, reactive oxygen species (ROS), malondialdehyde (MDA), activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), the content of glutathione (GSH) and mitochondrial membrane potential (MMP) and insulin secretion measurements. The lower viability of islet cells was dose-dependent due to the exposure to MWCNTs according to the MTT assay. Further studies revealed that MWCNTs decreased insulin secretion and MMP, induced ROS creation, increased the MDA level, and decreased activities of SOD, GSH-Px, CAT, and content of GSH. Furthermore, the pretreatment of islets with CA returned the changes. These findings indicated that MWCNTs might induce the oxidative stress of pancreatic islets occurring diabetes and protective CA effects that were mediated by the augmentation of the antioxidant defense system of islets. Our research suggested the necessity of conducting further studies on effects of MWCNTs and CA on the diabetes.

Protective effects of catalpol on mitochondria of hepatocytes in cholestatic liver injury

Cholestasis, which is caused by the obstruction of bile flow, can lead to rapid organ injury, cell apoptosis and necrosis of hepatocytes, and may eventually develop into fibrosis and cirrhosis. Oxidative stress and mitochondrial dysfunction are the key pathogenic signs of hepatic cholestasis. Catalpol has pharmacological activities, including antioxidative and anti-inflammatory effects, and may relieve mitochondrial damage and restore mitochondrial membrane potential. However, the potential roles and mechanisms of catalpol in cholestasis-induced liver injury are not clear. In the present study, liver function-related indexes were measured in the serum of mice by commercial kits. In addition, levels of serum inflammatory factors were detected by ELISA. Hematoxylin and eosin staining was performed to observe histopathological changes, and mitochondrial membrane potential was detected using JC-1 staining. Mitochondrial adenosine triphosphate (ATP), reactive oxygen species (ROS) and malondialdehyde levels were determined using a luciferase reporter kit, flow cytometry and a thiobarbituric acid reactive substance assay kit, respectively. Western blotting was performed to detect the expression levels of apoptosis-related proteins in liver tissues. The findings revealed that catalpol reduced liver damage caused by cholestasis, improved the mitochondrial membrane potential, and increased the ATP content and glutathione content of cholestasis model mice. Moreover, catalpol also reduced the ROS level, inhibited lipid peroxidation, and regulated oxidative stress and apoptotic protein expression. Thus, the present study preliminarily confirmed that catalpol can reduce liver injury in a mouse model of cholestasis through inhibiting oxidative stress and enhancing mitochondrial membrane potential.

Multi-walled carbon nanotubes induce oxidative stress, apoptosis, and dysfunction in isolated rat heart mitochondria: protective effect of naringin

Multi-walled carbon nanotubes (MWCNTs) are material with exclusive features that can be applied in different fields including industrial and medicine. It has been determined that the accumulation of MWCNTs in the organs is along with genotoxic and cytotoxic injuries. Previous studies have shown mitochondrial dysfunction in MWCNTs exposure with cell lines, but their exact mechanisms with isolated mitochondria have remained unclear. The present study evaluated toxicity induced by MWCNTs in isolated rat heart mitochondria and protective effect of naringin. Our results showed that MWCNTs toxicity caused the prevention of heart mitochondrial complex II activity. Treatment of isolated heart mitochondria with MWCNTs led to an increase in mitochondrial reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP) collapse, and mitochondrial malondialdehyde (MDA) and a decrease in mitochondrial glutathione (GSH) level and mitochondrial catalase (CAT) activity. Pretreatment of isolated heart mitochondria with naringin decreased mitochondrial oxidative damage through decreasing lipid peroxidation, returned mitochondrial complex II changes, decreasing MMP collapse and ROS production, and restoration of GSH level and CAT activity. Our findings indicated that MWCNTs had toxic effects on isolated heart mitochondria by inducing oxidative stress and possibly apoptosis pathway. The protection effects of naringin may be accompanied by mitochondrial conservation by its antioxidant property or due to its free radical scavenging. Our findings indicated that naringin had a possible role in preventing the mitochondria complaints in the heart.

Catalpol Exerts a Neuroprotective Effect in the MPTP Mouse Model of Parkinson's Disease

The degeneration of dopaminergic (DA) neurons in Parkinson’s disease (PD) is related to inflammation and oxidative stress. Anti-inflammatory agents could reduce the risk or slow the progression of PD. Catalpol, an iridoid glycoside extracted from the roots of Rehmannia radix, has been reported to reduce the release of inflammatory factors and exert neuroprotective effects. 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP)-treated mice were used as the PD model and the roles of catalpol on DA neurons and its potential mechanism were investigated in this study. We found that catalpol administration mitigated the loss of DA neurons induced by MPTP and increased exploratory behavior along with tyrosine hydroxylase (TH) expression, which was accompanied by astrocyte and microglia activation. Importantly, catalpol administration significantly inhibited MPTP-triggered oxidative stress, restored growth-associated protein 43 (GAP43) and vascular endothelial growth factor (VEGF) levels. Further, we found that catalpol suppressed the activation of MKK4/JNK/c-Jun signaling, and reduced the pro-inflammatory factors and inflammasome in the mouse model of PD. Our results suggest that catalpol relieves MPTP-triggered oxidative stress, which may benefit to avoid the occurrence of chronic inflammatory reaction. Catalpol alleviates MPTP-triggered oxidative stress and thereby prevents neurodegenerative diseases-related inflammatory reaction, highlighting its therapeutic potential for the management of PD symptoms.

Single-walled and multiwalled carbon nanotubes induce oxidative stress in isolated rat brain mitochondria

Single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) are broadly applicable across a variety of industrial fields. Despite their usefulness in many different applications, oxidative stress-induced toxicity of SWCNTs and MWCNTs has not been widely investigated. The present study examined the effects of SWCNTs and MWCNTs on rat brain mitochondria using the 3,4 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and indices of reactive oxygen species (ROS), based on measurements of malondialdehyde (MDA), glutathione (GSH), and mitochondrial membrane potential. Based on the MTT assay, exposure to SWCNTs and MWCNTs decreased mitochondrial survival and viability in a dose-dependent manner. Findings also indicated that MWCNTs and SWCNTs could damage mitochondrial membranes and induce the formation of ROS, as indicated by increased levels of MDA and decreased GSH content. The results of this study suggest that SWCNTs and MWCNTs likely damage brain tissue mitochondria by increasing oxidative stress and possibly activating the apoptosis pathway as well as other pathways of cytotoxicity.

Neuroprotective Effects of Gagam-Sipjeondaebo-Tang, a Novel Herbal Formula, against MPTP-Induced Parkinsonian Mice and MPP+-Induced Cell Death in SH-SY5Y Cells

Parkinson's disease is a neurodegenerative disease characterized by progressive cell death of dopaminergic neuron and following neurological disorders. Gagam-Sipjeondaebo-Tang (GST) is a novel herbal formula made of twelve medicinal herbs derived from Sipjeondaebo-Tang, which has been broadly used in a traditional herbal medicine. In the present study, we investigated the effects of GST against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced motor abnormalities in mice and 1-methyl-4-phenylpyridinium (MPP⁺)-induced neurotoxicity in SH-SY5Y cell. First, we found that GST alleviated motor dysfunction induced by MPTP, and the result showed dopaminergic neurons recovery in substantia nigra. In the cell experiment, pretreatment with GST increased the cell viability and attenuated apoptotic cell death in MPP⁺-treated SH-SY5Y cells. GST also inhibited reactive oxygen species production and restored the mitochondrial membrane potential loss, which were induced by MPP⁺. Furthermore, GST extract significantly activated ERK and Akt, cell survival-related proteins, in SH-SY5Y cells. The effect of GST preventing mitochondrial dysfunction was antagonized by pretreatment of PD98059 and LY294002, selective inhibitors of ERK and Akt, respectively. Taken together, GST alleviated abnormal motor functions and recovered neuronal cell death, mitochondrial dysfunction, possibly via ERK and Akt activation. Therefore, we suggest that GST may be a candidate for the treatment and prevention of Parkinson's disease.

Herbal Medicine Formulas for Parkinson's Disease: A Systematic Review and Meta-Analysis of Randomized Double-Blind Placebo-Controlled Clinical Trials

Background: Parkinson's disease (PD) is a debitlitating, chronic, progressive neurodegenerative disorder without modifying therapy. Here, we aimed to evaluate the available evidence of herbal medicine (HM) formulas for patients with PD according to randomized double-blind placebo-controlled clinical trials. Methods: HM formulas for PD were searched in eight main databases from their inception to February 2018. The methodological quality was assessed using Cochrane Collaboration risk of bias tool. Meta-analysis was performed using RevMan 5.3 software. Results: Fourteen trials with Seventeen comparisons comprising 1,311 patients were identified. Compared with placebo groups, HM paratherapy (n = 16 comparisons) showed significant better effects in the assessments of total Unified Parkinson's Disease Rating Scale (UPDRS) (WMD: -5.43, 95% CI:-8.01 to -2.86; P < 0.0001), UPDRS I (WMD: -0.30, 95% CI: -0.54 to -0.06; P = 0.02), UPDRS II (WMD: -2.21, 95% CI: -3.19 to -1.22; P < 0.0001), UPDRS III (WMD: -3.26, 95% CI:-4.36 to -2.16; P < 0.00001), Parkinson's Disease Quality of Life Questionnaire (p < 0.01) and Parkinson's Disease Questionnaire-39 (WMD: -7.65, 95% CI: -11.46 to -3.83; p < 0.0001), Non-motor Symptoms Questionnaire (p < 0.01) and Non-Motor Symptoms Scale (WMD: -9.19, 95% CI: -13.11 to -5.28; P < 0.00001), Parkinson's Disease Sleep Scale (WMD: 10.69, 95% CI: 8.86 to 12.53; P < 0.00001), and Hamilton depression rating scale (WMD: -5.87, 95% CI: -7.06 to -4.68; P < 0.00001). The efficiency of HM monotherapy (n = 1 comparison) was not superior to the placebo according to UPDRS II, UPDRS III and total UPDRS score in PD patients who never received levodopa treatment, all P > 0.05. HM formulas paratherapy were generally safe and well tolerated for PD patients (RR: 0.41, 95% CI: 0.21 to 0.80; P = 0.009). Conclusion: The findings of present study supported the complementary use of HM paratherapy for PD patients, whereas the question on the efficacy of HM monotherapy in alleviating PD symptoms is still open.

Da-Bu-Yin-Wan Improves the Ameliorative Effect of DJ-1 on Mitochondrial Dysfunction Through Augmenting the Akt Phosphorylation in a Cellular Model of Parkinson's Disease

Da-Bu-Yin-Wan (DBYW) is recorded originally in China over six centuries ago, and it is used to treat Parkinson’s disease (PD) clinically in recent decades. DJ-1 is a homodimeric protein linked to early-onset PD, and found in the mitochondria. In addition, DJ-1 could protect the cells by regulating gene transcription and modulating the Akt signal pathways. Therefore, in this research, we aimed to investigate the ameliorative effect of DBYW on mitochondria in the view of the DJ-1 and Akt signaling. Rat adrenal pheochromocytoma cell line PC-12 was transfected with the plasmid pcDNA3-Flag-DJ-1 (pDJ-1). Subsequently, PC-12 cells were exposed to the PD-related mitochondrial toxin (1-methyl-4-phenylpyridinium) without/with the DBYW. After transfected with the plasmid pDJ-1, the 1-methyl-4-phenylpyridinium-induced toxicity was decreased, and the DJ-1 expression in protein level was increased. DJ-1 overexpression not only increased the mitochondrial mass, but also improved the total ATP content. Moreover, Akt phosphorylation was augmented by DJ-1 overexpression. Additionally, DBYW enhanced the above effects. Conclusively, these findings indicate that DBYW promotes the ameliorative effects of DJ-1 on mitochondrial dysfunction at least through augmenting the Akt phosphorylation in 1-methyl-4-phenylpyridinium-treated PC-12 cells.

Catalpol Inhibits Ischemia-Induced Premyelinating Oligodendrocyte Damage through Regulation of Intercellular Calcium Homeostasis via Na⁺/Ca2+ Exchanger 3

The heightened vulnerability of premyelinating oligodendrocytes (PreOLs) in response to hypoxia⁻ischemia may contribute to perinatal white matter injury and subsequent neurobehavioral dysfunction. Intracellular Ca²⁺ overload is considered a crucial mechanism predisposing PreOLs to ischemic injury. We previously reported that catalpol, an iridoid glycoside extracted from Rehmannia root, inhibits intracellular Ca²⁺ overload of PreOLs in an in vitro ischemia model. However, the exact underlying mechanisms remain elusive. In the present study, we aimed to investigate the protective effects of catalpol on PreOLs and to explore the underlying mechanisms involved in the modulation of intracellular Ca²⁺ homeostasis. Postnatal day 2 (P2) Sprague-Dawley (SD) rats subjected to bilateral common carotid artery ligation followed by exposure to 8% oxygen for 10 min were used as a rat model of neonatal hypoxia⁻ischemia. We found that catalpol significantly improved behavioral functions and prevented PreOL loss and myelination deficit after hypoxia⁻ischemia. Our in vitro studies also confirmed the direct effects of catalpol on oxygen-glucose deprivation (OGD)-induced cell death and arrested maturation of PreOLs. Moreover, we demonstrated that catalpol significantly inhibited intracellular Ca²⁺ overload and promoted the expression of Na⁺/Ca²⁺ exchanger 3 (NCX3). Finally, we found that catalpol significantly reduced mitochondrial damage and subsequent extracellular signal-regulated kinase 1/2 (ERK1/2) and poly-ADP-ribose polymerase-1 (PARP-1) activation. Treatment with NCX3-preferring inhibitor 2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea (KB-R7943) significantly reversed the protective effects of catalpol on PreOLs under OGD. Overall, our data suggest that catalpol protects PreOLs from ischemic injury through regulation of intercellular Ca²⁺ homeostasis via upregulation of NCX3 activity.

Mice pancreatic islets protection from oxidative stress induced by single-walled carbon nanotubes through naringin

The growing use of carbon nanotubes (CNTs) emphasizes the importance of its potential toxic effects on the human health. Previous studies proved that CNTs caused oxidative stress and decreased cell viability. On the other hand, reactive oxygen species (ROS) and oxidative stress impaired β-cell functions and reduced the insulin secretion. However, there is not any study on the effects of CNTs on islets and β-cells. Therefore, the present study aimed to evaluate the effects of single-walled CNTs (SWCNTs) on oxidative stress in islets in addition to the protective effects of naringin (NRG) as an antioxidant . We examined the effects of SWCNTs and naringin on islets by 3,4 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay; measurement of insulin secretion, ROS, and malondialdehyde (MDA); activities of superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) peroxidase (GSH-Px); and content of GSH and mitochondrial membrane potential (MMP). The MTT assay demonstrated that decreased viability of islets cells was dose-dependent with exposure to SWCNTs. Further studies revealed that SWCNTs decreased insulin secretion and MMP, induced the formation of ROS, increased the level of MDA, and decreased the activities of SOD, GSH-Px, and CAT and content of GSH. Furthermore, the pretreatment of islets with naringin significantly reverted back these changes. These findings revealed that SWCNTs might induce the oxidative stress to pancreatic islets, causing the occurrence of diabetes, and the protective effects of naringin that was mediated by augmentation of the antioxidant defense system of islets. Our research indicated the necessity for further in vivo and in vitro researches on the effects of SWCNTs and naringin on diabetes.

Catalpol Inhibits Amyloid-β Generation Through Promoting α-Cleavage of APP in Swedish Mutant APP Overexpressed N2a Cells

Amyloid-β (Aβ) peptides play a crucial role in the pathogenesis of Alzheimer's disease (AD), due to its neurotoxicity. Thus, blocking Aβ generation and aggregation in the brain has been realized as an efficient way for the prevention of AD. The natural product catalpol, isolated from Rehmannia glutinosa, has shown neuroprotective activities through inhibiting soluble Aβ production, degrading Aβ peptide, and attenuating Aβ toxicity and neuroinflammatory responses. In the present study, we aimed to evaluate whether catalpol reduce Aβ generation associated with regulating amyloid precursor protein (APP) proteolytic processing. By using Swedish mutant APP overexpressed N2a (SweAPP N2a) cells treated with catalpol, we found that catalpol was not able to reduce the expression levels of β-secretase (BACE-1) and γ-secretase (PS1, APH-1, PEN-2 and Nicastrin). By contrast, catalpol had a significant promotion effect on the expression of α-secretase (ADAM10) and its proteolytic products, sAPPα and C83, suggesting that catalpol reduced the production of Aβ might be involved in non-amyloidogenic APP pathway. In addition, we confirmed that the extracellular signal-related kinase/cAMP-response element binding protein (ERK/CREB) signaling pathways were responsible for the up-regulation of ADAM10 in catalpol-treated SweAPP N2a cells. The present data, for the first time, have demonstrated that the effect of catalpol on the inhibiting Aβ generation might be closely related to α-cleavage of APP processing.

An adverse outcome pathway for parkinsonian motor deficits associated with mitochondrial complex I inhibition

Epidemiological studies have observed an association between pesticide exposure and the development of Parkinson's disease, but have not established causality. The concept of an adverse outcome pathway (AOP) has been developed as a framework for the organization of available information linking the modulation of a molecular target [molecular initiating event (MIE)], via a sequence of essential biological key events (KEs), with an adverse outcome (AO). Here, we present an AOP covering the toxicological pathways that link the binding of an inhibitor to mitochondrial complex I (i.e., the MIE) with the onset of parkinsonian motor deficits (i.e., the AO). This AOP was developed according to the Organisation for Economic Co-operation and Development guidelines and uploaded to the AOP database. The KEs linking complex I inhibition to parkinsonian motor deficits are mitochondrial dysfunction, impaired proteostasis, neuroinflammation, and the degeneration of dopaminergic neurons of the substantia nigra. These KEs, by convention, were linearly organized. However, there was also evidence of additional feed-forward connections and shortcuts between the KEs, possibly depending on the intensity of the insult and the model system applied. The present AOP demonstrates mechanistic plausibility for epidemiological observations on a relationship between pesticide exposure and an elevated risk for Parkinson's disease development.

Catalpol Protects Pre-Myelinating Oligodendrocytes against Ischemia-induced Oxidative Injury through ERK1/2 Signaling Pathway

The vulnerability of pre-myelinating oligodendrocytes (PreOLs) to ischemic injury plays an important role in the pathogenesis and progression of perinatal white matter injury. Although oxidative stress is thought to be a major pathogenic mechanism predisposing the PreOLs to injury, no effective therapies have been identified to date. The present study aimed to investigate the direct protective effects of catalpol, a potent antioxidant and free radical scavenger, on ischemia-induced oxidative damage in PreOLs and to explore whether the ERK1/2 signaling pathway contributed to the protection provided by catalpol. Primary cultures of PreOLs exposed to oxygen-glucose deprivation (OGD) followed by reperfusion were used as an in vitro model of ischemia. Pretreatment with 0.5 mM catalpol for 1 h prior to OGD treatment significantly reversed ischemia-induced apoptosis in PreOLs and myelination deficits by inhibiting intracellular Ca²⁺ increase, reducing mitochondrial damage, and ameliorating overproduction of reactive oxygen species (ROS). The expression levels of phosphorylated ERK1/2 (p-ERK1/2) and activated poly-ADP-ribose polymerase-1 (PARP-1) were also markedly decreased by catalpol treatment. Blocking the ERK1/2 signaling pathway with the MEK inhibitor U0126 and catalpol significantly protected PreOLs from ROS-mediated apoptosis under OGD. Taken together, these results suggest that catalpol protects PreOLs against ischemia-induced oxidative injury through ERK1/2 signaling pathway. Catalpol may be a candidate for treating ischemic white matter damage.

The metabolites of glutamine prevent hydroxyl radical-induced apoptosis through inhibiting mitochondria and calcium ion involved pathways in fish erythrocytes

The present study explored the apoptosis pathways in hydroxyl radicals ((∙)OH)-induced carp erythrocytes. Carp erythrocytes were treated with the caspase inhibitors in physiological carp saline (PCS) or Ca(2+)-free PCS in the presence of 40μM FeSO4/20μM H2O2. The results showed that the generation of reactive oxygen species (ROS), the release of cytochrome c and DNA fragmentation were caspase-dependent, and Ca(2+) was involved in calpain activation and phosphatidylserine (PS) exposure in (∙)OH-induced carp erythrocytes. Moreover, the results suggested that caspases were involved in PS exposure, and Ca(2+) was involved in DNA fragmentation in (∙)OH-induced fish erythrocytes. These results demonstrated that there might be two apoptosis pathways in fish erythrocytes, one is the caspase and cytochrome c-dependent apoptosis that is similar to that in mammal nucleated cells, the other is the Ca(2+)-involved apoptosis that was similar to that in mammal non-nucleated erythrocytes. So, fish erythrocytes may be used as a model for studying oxidative stress and apoptosis in mammal cells. Furthermore, the present study investigated the effects of glutamine (Gln)'s metabolites [alanine (Ala), citrulline (Cit), proline (Pro) and their combination (Ala10Pro4Cit1)] on the pathways of apoptosis in fish erythrocytes. The results displayed that Ala, Cit, Pro and Ala10Pro4Cit1 effectively suppressed ROS generation, cytochrome c release, activation of caspase-3, caspase-8 and caspase-9 at the physiological concentrations, prevented Ca(2+) influx, calpain activation, PS exposure, DNA fragmentation and the degradation of the cytoskeleton and oxidation of membrane and hemoglobin (Hb) and increased activity of anti-hydroxyl radical (AHR) in (∙)OH-induced carp erythrocytes. Ala10Pro4Cit1 produced a synergistic effect of inhibited oxidative stress and apoptosis in fish erythrocytes. These results demonstrated that Ala, Cit, Pro and their combination can protect mammal erythrocytes and nucleated cells against oxidative stress and apoptosis. The studies supported the use of Gln, Ala, Cit and Pro as oxidative stress and apoptosis inhibitors in mammal cells and the hypothesis that the inhibited effects of Gln on oxidative stress and apoptosis are at least partly dependent on that of its metabolites in mammalian.

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.

Ca(2+) and caspases are involved in hydroxyl radical-induced apoptosis in erythrocytes of Jian carp (Cyprinus carpio var. Jian)

There are young erythrocytes and mature erythrocytes in the peripheral blood of fish. The present study explored the apoptosis in hydroxyl radical ((·)OH)-induced young and mature erythrocytes of Jian carp (Cyprinus carpio var. Jian). Carp erythrocytes from the peripheral blood were separated into the young fraction, the intermediate fraction and the mature fraction using fixed-angle centrifugation. The erythrocytes in three age fractions were treated with the caspase inhibitors (zVAD-fmk) in physiological carp saline (PCS) or Ca(2+)-free PCS in the presence of 40 μM FeSO4/20 μM H2O2. The results showed that the (·)OH-induced reactive oxygen species (ROS) generation, phosphatidylserine (PS) exposure and DNA fragmentation are caspase dependent in carp erythrocytes. Furthermore, the ROS generation, PS exposure and DNA fragmentation in the more young fraction are more dependent on the caspase activity. This suggested that the caspases are involved in the (·)OH-induced apoptosis in the young erythrocytes of fish. Results also indicated that Ca(2+) is involved in (·)OH-induced calpain activation, PS exposure and DNA fragmentation in carp erythrocytes. Moreover, the calpain activation, DNA fragmentation and PS exposure in the more mature fraction are more dependent on the levels of Ca(2+). This revealed that (·)OH-induced apoptosis is Ca(2+) dependent in the mature erythrocytes of fish. Taken together, there might be two apoptosis pathways in fish erythrocytes: one is the caspase-dependent apoptosis in the young erythrocytes and the other is the Ca(2+)-involved apoptosis in the mature erythrocytes.

Mitochondrial permeability transition and its regulatory components are implicated in apoptosis of primary cultures of rat proximal tubular cells exposed to lead

Previous studies have already demonstrated that mitochondria play a key role in Pb-induced apoptosis in primary cultures of rat proximal tubular (rPT) cells. To further clarify the underlying mechanism of Pb-induced mitochondrial apoptosis, this study was designed to investigate the role of mitochondrial permeability transition (MPT) and its regulatory components in Pb-induced apoptosis in rPT cells. Mitochondrial permeability transition pore (MPTP) opening together with disruption of mitochondrial ultrastructure, translocation of cytochrome c from mitochondria to cytoplasm and subsequent caspase-3 activation were observed in this study, suggesting that MPT is involved in Pb-induced apoptosis in rPT cells. Simultaneously, Pb-induced caspase-3 activation and apoptosis can be significantly inhibited by three MPTP inhibitors (CsA, DIDS, BA), which target different regulatory components of MPTP (Cyp-D, VDAC, ANT), respectively, demonstrating that Cyp-D, VDAC and ANT participate in MPTP regulation during lead exposure. Moreover, decreased ATP levels and increased ADP/ATP ratio induced by lead treatment can be significantly reversed by BA, indicating that Pb-mediated ANT dysfunction resulted in ATP depletion. In addition, up-regulation of VDAC-1, ANT-1 together with down-regulation of Cyp-D, VDAC-2 and ANT-2 at both the levels of transcription and translation were revealed in rPT cells under lead exposure conditions. In conclusion, Pb-mediated mitochondrial apoptosis in rPT cells is dependent on MPTP opening. Different expression levels in each isoform of three regulatory components contribute to alteration in their functions, which may promote the MPTP opening.

Catalpol regulates cholinergic nerve system function through effect on choline acetyl-transferase not M receptor affinity

OBJECTIVE

To explore the effect of catalpol on choline acetyl-transferase and M receptor affinity in a PC12 cell model and a rat model induced by beta-amyloid 25-35 (Aβ25-35).

METHODS

In PC12 cells, catalpol (10μmol/l, 100μmol/) or saline was retained in the medium and Aβ25-35 (final concentration 20μmol/l) was added. Choline acetyl-transferase (ChAT) expression was determined by immunocytochemistry, ChAT activity measured by radioenzymatic assay, and M receptor (muscarinic receptor) affinity determined by (3)H-QNB binding test. In Wistar rats, Aβ25-35 was injected intracerebroventricularly to establish AD model. After injection of Aβ25-35, the rats were injected catalpol at 5 and 10mg/kgd(-1) intraperitoneally for the next 7 days, and saline for the control rats. ChAT expression, ChAT activity and M receptor affinity were tested. Cells and rats all were divided into four groups: Group A (control), Group B (model), Group C (catalpol low dose), and Group D (catalpol high dose).

RESULTS

Compared with control, both PC12 cell and rat AD models showed decreased expression and activity of ChAT (p<0.01), but M receptor affinity remained the same (p>0.05). Compared with model group, treatment of catalpol increased expression and activity of ChAT of PC12 cell and rat AD model induced by Aβ25-35, p<0.05 or p<0.01 respectively. But there was no difference of M receptor affinity among the four groups (p>0.05). M receptor affinity remained the same as concentration of catalpol increased gradually in atropine competition experiments (p>0.05).

CONCLUSIONS

Catalpol could regulate the cholinergic nerve system function from its effect on ChAT and may have beneficial effect for treatment of AD, but had no effect on M receptor affinity.

Hypoglycemic effect of catalpol on high-fat diet/streptozotocin-induced diabetic mice by increasing skeletal muscle mitochondrial biogenesis

Catalpol, an iridoid glycoside, exists in the root of Radix Rehmanniae. Some studies have shown that catalpol has a remarkable hypoglycemic effect in the streptozotocin-induced diabetic model, but the underlying mechanism for this effect has not been fully elucidated. Because mitochondrial dysfunction plays a vital role in the pathology of diabetes and because improving mitochondrial function may offer a new approach for the treatment of diabetes, this study was designed. Catalpol was orally administered together with metformin to high-fat diet/streptozotocin (HFD/STZ)-induced diabetic mice daily for 4 weeks. Body weight (BW), fasting blood glucose (FBG) level, and glucose disposal (IPGTT) were measured during or after the treatment. The results showed a dose-dependent reduction of FBG level with no apparent changes in BW through four successive weeks of catalpol administration. Catalpol treatment substantially reduced serum total cholesterol and triglyceride levels in the diabetic mice. In addition, catalpol efficiently increased mitochondrial ATP production and reversed the decrease of mitochondrial membrane potential and mtDNA copy number in skeletal muscle tissue. Furthermore, catalpol (200 mg/kg) rescued mitochondrial ultrastructure in skeletal muscle, as detected with transmission electron microscopy. The relative mRNA level of peroxisome proliferator-activated receptor gamma co-activator 1 (PGC1) α was significantly decreased in muscle tissue of diabetic mice, while this effect was reversed by catalpol, resulting in a dose-dependent up-regulation. Taken together, we found that catalpol was capable of lowering FBG level via improving mitochondrial function in skeletal muscle of HFD/STZ-induced diabetic mice.

Selective MAO-B inhibitors: a lesson from natural products

Monoamine oxidases (MAOs) are mitochondrial bound enzymes, which catalyze the oxidative deamination of monoamine neurotransmitters. Inside the brain, MAOs are present in two isoforms: MAO-A and MAO-B. The activity of MAO-B is generally higher in patients affected by neurodegenerative diseases like Alzheimer's and Parkinson's. Therefore, the search for potent and selective MAO-B inhibitors is still a challenge for medicinal chemists. Nature has always been a source of inspiration for the discovery of new lead compounds. Moreover, natural medicine is a major component in all traditional medicine systems. In this review, we present the latest discoveries in the search for selective MAO-B inhibitors from natural sources. For clarity, compounds have been classified on the basis of structural analogy or source: flavonoids, xanthones, tannins, proanthocyanidins, iridoid glucosides, curcumin, alkaloids, cannabinoids, and natural sources extracts. MAO inhibition values reported in the text are not always consistent due to the high variability of MAO sources (bovine, pig, rat brain or liver, and human) and to the heterogeneity of the experimental protocols used.

Validated LC-MS method for simultaneous quantitation of catalpol and harpagide in rat plasma: application to a comparative pharmacokinetic study in normal and diabetic rats after oral administration of Zeng-Ye-Decoction

A simple and efficient liquid chromatography-mass spectrometry (LC-MS) method was developed and validated for simultaneous quantitation of catalpol and harpagide in normal and diabetic rat plasma. Protein precipitation extraction with acetonitrile was carried out using salidroside as the internal standard (IS). The LC separation was performed on an Elite C18 column (150 × 4.6 mm, 5 µm) with the mobile phase consisting of acetonitrile and water within a runtime of 12.0 min. The analytes were detected without endogenous interference in the selected ion monitoring mode with positive electrospray ionization. Calibration curves offered satisfactory linearity (r > 0.99) at linear range of 0.05-50.0 µg/mL for catalpol and 0.025-5.0 µg/mL for harpagide with the lower limits of quantitation of 0.05 and 0.025 µg/mL, respectively. Intra- and inter-day precisions (RSD) were <9.4%, and accuracy (RE) was in the -6.6 to 4.9% range. The extraction efficiencies of catalpol, harpagide and IS were all >76.5% and the matrix effects of the analytes ranged from 86.5 to 106.0%. The method was successfully applied to the pharmacokinetic study of catalpol and harpagide after oral administration of Zeng-Ye-Decoction to normal and diabetic rats, respectively.

Catalpol inhibits LPS plus IFN-γ-induced inflammatory response in astrocytes primary cultures

A large body of evidence suggests that the inflammatory reaction plays an important role in the pathogenesis of neurodegenerative diseases. Our previous studies described the neuroprotective effects of catalpol in lipopolysaccharide (LPS)-induced inflammatory models, in which catalpol was shown to prevent mesencephalic neuron death and ameliorate cognitive ability animals. To further investigate the protective effect and underlying mechanism of catalpol, astrocytes were pretreated with low (0.1mM) and high dose (0.5mM) catalpol for 1h prior to LPS plus interferon-γ stimulation. Biochemical analyses showed that NO and ROS production and iNOS activity were significantly reduced by catalpol. Data at transcriptional level also demonstrated that catalpol potently attenuated gene expressions involved in inflammation, such as iNOS, COX-2 and TLR4. In addition, our exploration further revealed that the suppressive action of catalpol on inflammation was mediated via inhibiting nuclear factor-κB (NF-κB) activation. Collectively, these results suggest that catalpol can exert inhibitory effects on the inflammatory reaction in astrocytes and that inactivation of NF-κB could be the major determinant for its anti-inflammatory mechanism. Therefore, catalpol may potentially be a highly effective therapeutic agent in treating neurodegenerative diseases associated with inflammation.

Transcriptome analysis reveals putative genes involved in iridoid biosynthesis in Rehmannia glutinosa

Rehmannia glutinosa, one of the most widely used herbal medicines in the Orient, is rich in biologically active iridoids. Despite their medicinal importance, no molecular information about the iridoid biosynthesis in this plant is presently available. To explore the transcriptome of R. glutinosa and investigate genes involved in iridoid biosynthesis, we used massively parallel pyrosequencing on the 454 GS FLX Titanium platform to generate a substantial EST dataset. Based on sequence similarity searches against the public sequence databases, the sequences were first annotated and then subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) based analysis. Bioinformatic analysis indicated that the 454 assembly contained a set of genes putatively involved in iridoid biosynthesis. Significantly, homologues of the secoiridoid pathway genes that were only identified in terpenoid indole alkaloid producing plants were also identified, whose presence implied that route II iridoids and route I iridoids share common enzyme steps in the early stage of biosynthesis. The gene expression patterns of four prenyltransferase transcripts were analyzed using qRT-PCR, which shed light on their putative functions in tissues of R. glutinosa. The data explored in this study will provide valuable information for further studies concerning iridoid biosynthesis.

Astrocytes and microglia: responses to neuropathological conditions

Activated astrocytes and microglia, hallmark of neurodegenerative diseases release different factors like array of pro and anti-inflammatory cytokines, free radicals, anti-oxidants, and neurotrophic factors during neurodegeneration which further contribute to neuronal death as well as in survival mechanisms. Astrocytes act as double-edged sword exerting both detrimental and neuroprotective effects while microglial cells are attributed more in neurodegenerative mechanisms. The dual and insufficient knowledge about the precise role of glia in neurodegeneration showed the need for further investigations and thorough review of the function of glia in neurodegeneration. In this review, we consolidate and categorize the glia-released factors which contribute in degenerative and protective mechanisms during neuropathological conditions.

Traditional chinese medicine for senile dementia

Traditional Chinese Medicine (TCM) has a 3000 years' history of human use. A literature survey addressing traditional evidence from human studies was done, with key result that top 10 TCM herb ingredients including Poria cocos, Radix polygalae, Radix glycyrrhizae, Radix angelica sinensis, and Radix rehmanniae were prioritized for highest potential benefit to dementia intervention, related to the highest frequency of use in 236 formulae collected from 29 ancient Pharmacopoeias, ancient formula books, or historical archives on ancient renowned TCM doctors, over the past 10 centuries. Based on the history of use, there was strong clinical support that Radix polygalae is memory improving. Pharmacological investigation also indicated that all the five ingredients mentioned above can elicit memory-improving effects in vivo and in vitro via multiple mechanisms of action, covering estrogen-like, cholinergic, antioxidant, anti-inflammatory, antiapoptotic, neurogenetic, and anti-Aβ activities. Furthermore, 11 active principles were identified, including sinapic acid, tenuifolin, isoliquiritigenin, liquiritigenin, glabridin, ferulic acid, Z-ligustilide, N-methyl-beta-carboline-3-carboxamide, coniferyl ferulate and 11-angeloylsenkyunolide F, and catalpol. It can be concluded that TCM has a potential for complementary and alternative role in treating senile dementia. The scientific evidence is being continuously mined to back up the traditional medical wisdom.

The biochemical and cellular basis for nutraceutical strategies to attenuate neurodegeneration in Parkinson's disease

Future therapeutic intervention that could effectively decelerate the rate of degeneration within the substantia nigra pars compacta (SNc) could add years of mobility and reduce morbidity associated with Parkinson’s disease (PD). Neurodegenerative decline associated with PD is distinguished by extensive damage to SNc dopaminergic (DAergic) neurons and decay of the striatal tract. While genetic mutations or environmental toxins can precipitate pathology, progressive degenerative succession involves a gradual decline in DA neurotransmission/synaptic uptake, impaired oxidative glucose consumption, a rise in striatal lactate and chronic inflammation. Nutraceuticals play a fundamental role in energy metabolism and signaling transduction pathways that control neurotransmission and inflammation. However, the use of nutritional supplements to slow the progression of PD has met with considerable challenge and has thus far proven unsuccessful. This review re-examines precipitating factors and insults involved in PD and how nutraceuticals can affect each of these biological targets. Discussed are disease dynamics (Sections 1 and 2) and natural substances, vitamins and minerals that could impact disease processes (Section 3). Topics include nutritional influences on α-synuclein aggregation, ubiquitin proteasome function, mTOR signaling/lysosomal-autophagy, energy failure, faulty catecholamine trafficking, DA oxidation, synthesis of toxic DA-quinones, o-semiquinones, benzothiazolines, hyperhomocyseinemia, methylation, inflammation and irreversible oxidation of neuromelanin. In summary, it is clear that future research will be required to consider the multi-faceted nature of this disease and re-examine how and why the use of nutritional multi-vitamin-mineral and plant-based combinations could be used to slow the progression of PD, if possible.

Astaxanthin protects against MPTP/MPP+-induced mitochondrial dysfunction and ROS production in vivo and in vitro

Astaxanthin (AST) is a powerful antioxidant that occurs naturally in a wide variety of living organisms. We have investigated the role of AST in preventing 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced apoptosis of the substantia nigra (SN) neurons in the mouse model of Parkinson's disease (PD) and 1-methyl-4-phenylpyridinium (MPP+)-induced cytotoxicity of SH-SY5Y human neuroblastoma cells. In in vitro study, AST inhibits MPP+-induced production of intracellular reactive oxygen species (ROS) and cytotoxicity in SH-SY5Y human neuroblastoma cells. Preincubation of AST (50 μM) significantly attenuates MPP+-induced oxidative damage. Furthermore, AST is able to enhance the expression of Bcl-2 protein but reduce the expression of α-synuclein and Bax, and suppress the cleavage of caspase-3. Our results suggest that the protective effects of AST on MPP+-induced apoptosis may be due to its anti-oxidative properties and anti-apoptotic activity via induction of expression of superoxide dismutase (SOD) and catalase and regulating the expression of Bcl-2 and Bax. Pretreatment with AST (30 mg/kg) markedly increases tyrosine hydroxylase (TH)-positive neurons and decreases the argyrophilic neurons compared with the MPTP model group. In summary, AST shows protection from MPP+/MPTP-induced apoptosis in the SH-SY5Y cells and PD model mouse SN neurons, and this effect may be attributable to upregulation of the expression of Bcl-2 protein, downregulation of the expression of Bax and α-synuclein, and inhibition of the activation of caspase-3. These data indicate that AST may provide a valuable therapeutic strategy for the treatment of progressive neurodegenerative disease such as Parkinson's disease.