Protective effects of Choto-san and hooks and stems of Uncaria sinensis against delayed neuronal death after transient forebrain ischemia in gerbil

Advanced researches of traditional uses, phytochemistry, pharmacology, and toxicology of medical Uncariae Ramulus Cum Uncis

ETHNOPHARMACOLOGICAL RELEVANCE

Medical Uncariae Ramulus Cum Uncis consists of Uncaria rhynchophylla (Miq.) Miq. ex Havil, Uncaria macrophylla Wall, Uncaria sinensis (Oliv.) Havil, Uncaria hirsuta Havil, and Uncaria sessilifructus Roxb, which belongs to the species widely used in the genus Uncaria. These species resource widely distributed in China and abroad, and the hook-bearing stem is the primary constituent enrichment site. There are many different forms and architectures of chemicals, depending on the extraction site. Traditional remedies employing URCU had been used widely in antiquity and were first compiled in renowned ancient masterpiece 'Mingyi Bielu ()' written by Hongjing Tao. In modern pharmacological studies, both the total extracts and the phytoconstituents isolated from URCU have been shown to have neuroprotective, antioxidant, anti-inflammatory, anticancer, antibacterial, and autophagy-enhancer properties.

AIM OF THE STUDY

This review concentrates on the traditional uses, phytochemistry, pharmacology, toxicology, and nanomaterials studies of URCU, with a perspective to assist with further research and advance.

MATERIAL AND METHODS

The Chinese and English literature studies of this review are based on these database searches including Science Direct, CNKI, Wiley online library, Spring Link, Web of Science, PubMed, Medalink, Google scholar, Elsevier, ACS Publications, iPlant, Missouri Botanical Garden, Plant of the World Online. The pertinent data on URCU was gathered.

RESULTS

Based on the examination of the genus Uncaria, 107 newly marked chemical compositions have been identified from URCU from 2015 to present, including alkaloids, terpenoids, flavonoids, steroids, and others. Pharmacological studies have demonstrated that URCU has a variety of benefits in diseases such as neurodegenerative diseases, cancer, cardiovascular diseases, diabetes, and migraine, due to its neuroprotective, anti-inflammatory, antioxidant, anti-tumor, anti-bacterial and anti-viral properties. According to metabolic and toxicological studies, the dosage, frequency, and interactions of the drugs that occur in vivo are of great significance for determining whether the organic bodies can perform efficacy or produce toxicity. The research on URCU-mediated nanomaterials is expanding and increasing in order to address the inadequacies of conventional Chinese medicine. The alkaloids in URCU have the capability to self-assemble with other classes of components in addition to being biologically active.

CONCLUSION

URCU plants are widely distributed, abundant in chemical constituents, and widely used in both traditional and modern medicine for a variety of pharmacological effects. The utilization of herbal medicines can be raised by assessing the pharmacological distinctions among several species within the same genus and may accelerate the modernization of traditional Chinese medicine. Controlling the concentration of drug administration, monitoring metabolic markers, and inventing novel nanotechnologies are effective strategies for synergistic influence and detoxification to alleviate the main obstacles that toxicity, low bioavailability, and poor permeability. This review can assist further research and advances.

Neuroprotective Effects of Medicinal Plants in Cerebral Hypoxia and Anoxia: A Systematic Review

Background:

Hypoxia and anoxia are dangerous and sometimes irreversible complications in the central nervous system (CNS), which in some cases lead to death.

Objective:

The aim of this review was to investigate the neuroprotective effects of medicinal plants in cerebral hypoxia and anoxia.

Methods:

The word hypox*, in combination with some herbal terms such as medicinal plant, phyto* and herb*, was used to search for relevant publications indexed in the Institute for Scientific Information (ISI) and PubMed from 2000-2019.

Results:

Certain medicinal plants and herbal derivatives can exert their protective effects in several ways. The most important mechanisms are the inhibition of inducible nitric oxide synthase (iNOS), production of NO, inhibition of both hypoxia-inducible factor 1α and tumor necrosis factor-alpha activation, and reduction of extracellular glutamate, N-Methyl-D-aspartic and intracellular Ca (2+). In addition, they have an antioxidant activity and can adjust the expression of genes related to oxidant generation or antioxidant capacity. These plants can also inhibit lipid peroxidation, up-regulate superoxide dismutase activity and inhibit the content of malondialdehyde and lactate dehydrogenase. Moreover, they also have protective effects against cytotoxicity through down-regulation of the proteins that causes apoptosis, anti-excitatory activity, inhibition of apoptosis signaling pathway, reduction of pro-apoptotic proteins, and endoplasmic reticulum stress that causes apoptosis during hypoxia, increasing anti-apoptotic protein, inhibition of protein tyrosine kinase activation, decreasing proteases activity and DNA fragmentation, and upregulation of mitochondrial cytochrome oxidase.

Conclusion:

The results indicated that medicinal plants and their compounds mainly exert their neuroprotective effects in hypoxia via regulating proteins that are related to antioxidant, anti-apoptosis and anti-inflammatory activities.

Choto-san versus placebo for patients with dementia: systematic review and meta-analysis

BACKGROUND

Choto-san is a traditional medicine used for hypertension and headaches in Japan and China. Some studies have shown its effectiveness in the treatment of dementia. The present review aimed to assess the effectiveness and acceptability of Choto-san in the treatment of adults with cognitive impairment.

METHODS

We included randomized controlled trials comparing Choto-san with placebo for patients with dementia or mild cognitive impairment.

RESULTS

Three randomized controlled trials evaluating 219 participants were included. Two were studies on vascular dementia, and the other was on Alzheimer's dementia. There was no difference between Choto-san and placebo in terms of short-term dichotomous judgement of improvement, but Choto-san was more effective than placebo in terms of short-term improvement of cognitive function as measured by continuous outcomes. Also, dropouts judged it to be acceptable. However, the results were imprecise and/or heterogeneous. The number of participants included in the analysis was small (n = 199 in the primary analysis) and sometimes inconsistent, as indicated by the large I ² (72% in the primary analysis).

CONCLUSION

Low-quality evidence was suggestive of Choto-san's efficacy for vascular dementia, but the present results may be overestimated. Studies with a larger sample size and conducted over longer periods should be performed. Regardless, Choto-san can be one of the choices for the treatment of vascular dementia as it is well tolerated.

Water extract of Uncaria sinensis suppresses RANKL-induced bone loss by attenuating osteoclast differentiation and bone resorption

Background

The hooks and stems of Uncaria sinensis have been used to mitigate cardiovascular and central nervous system disorders in Asia traditional medicine. Regulation of osteoclast differentiation and activity is a major target for preventing and treating pathological bone diseases.

Methods

Tartrate-resistant acid phosphatase (TRAP) activity and the number of TRAP-stained multinucleated cells were used to examine receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation. The activation of RANKL-induced signaling pathways and the expression of transcription factors were investigated by western blot analysis and quantitative real-time polymerase chain reaction. The bone resorption activity of osteoclast was studied using a plate coated with hydroxyl-apatite. Trabecular bone destruction was investigated using a RANKL-induced trabecular bone loss mouse model.

Results

We found that water extract of the hooks and stems of U. sinensis (WEUS) inhibits RANKL-induced differentiation of murine bone marrow macrophages and RAW264.7 cells into osteoclasts. WEUS inhibited the activation of NF-κB and the expression of nuclear factor of activated T-cells, cytoplasmic 1. In addition, WEUS suppressed the bone resorbing activity of mature osteoclasts without affecting their survival. Furthermore, oral administration of WEUS suppressed RANKL-induced bone loss with a significant amelioration of trabecular bone micro-structures. WEUS also reduced RANKL-induced increase in serum TRAP5b activity and C-terminal cross-linked telopeptide of type I collagen levels.

Conclusion

The present study demonstrates that WEUS has a pharmacological activity that inhibits osteoclast-mediated bone destruction by suppressing osteoclast differentiation and function. These results suggest that U. sinensis could be a promising herbal candidate for preventing and treating bone diseases such as osteoporosis.

Gastrodia and Uncaria (tianma gouteng) water extract exerts antioxidative and antiapoptotic effects against cerebral ischemia in vitro and in vivo

BACKGROUND

Gastrodia and Uncaria decoction (tianma gouteng yin) is commonly used in Chinese medicine to treat cerebral ischemia. The aim of this study was to investigate the neuroprotective effects of a water extract (GUW) of Gastrodia elata (tianma; GE) and Uncaria rhynchophylla (gouteng; UR) against ischemic insult using oxygen-glucose-deprived neuronal differentiated PC12 cells and rats subjected to middle cerebral artery occlusion (MCAO).

METHODS

GUW was prepared by boiling raw GE and UR in water, followed by the lyophilization of the resulting extract. Neuronal differentiated PC12 cells were subjected to oxygen-glucose deprivation with or without GUW. The neuroprotective effects of GUW were compared with those of the corresponding GE and UR extracts to tease apart the effects of the different herbs. The synergistic effect of GE and UR in GUW was measured using a modified version of Burgi's formulae. The neuroprotective mechanisms via Nrf2 and anti-apoptotic pathways were investigated using real time PCR and enzyme activity assays. The neuroprotective effects of GUW were studied in vivo using a rat MCAO model. Neurofunctional outcome and brain infarct volume we assessed. H&E staining, cresyl violet staining and immunohistochemistry were performed to assess the histological outcome.

RESULTS

The results of lactate dehydrogenase assay showed that GUW protected cells in a concentration-dependent manner (P < 0.001). Moreover, the neuroprotective effects of GUW were greater than those of GE + UR (P = 0.018). Burgi's formula showed that the herbs in GUW acted synergistically to protect cells from ischemic injury. GUW significantly upregulated Bcl-2 expression (P = 0.0130) and reduced caspase-3 activity by 60 % (P < 0.001). GUW upregulated Nrf-2 expression (P = 0.0066) and the antioxidant response element pathway genes. The infarct volume was reduced by 55 % at day 7 of reperfusion (P < 0.001), and significant improvements were observed in the neurological deficit score and beam-walking test at 7 days (P < 0.001). H&E and cresyl violet staining revealed higher tissue integrity in the GUW treatment group compared with MCAO rats.

CONCLUSION

GUW modulated the antioxidant system and antiapoptotic genes in oxygen-glucose deprived neuronal differentiated PC12 cells and MCAO sprague-dawley rats.

Anti-Neuroinflammatory Effects of Uncaria sinensis in LPS-Stimulated BV2 Microglia Cells and Focal Cerebral Ischemic Mice

Uncaria sinensis (US) has long been used as a traditional Korean medicine to treat cardiovascular and central nervous system diseases, including hypertension and cerebral ischemia. Several recent studies have indicated that US has neuroprotective and cerebrovascular protective effects in ischemic brain injury; however, little is known about the anti-inflammatory effects of US. Therefore, the present study was designed to validate the anti-inflammatory effects of US. The anti-neuroinflammatory properties of US on pro-inflammatory mediators were investigated in lipopolysaccharide (LPS)-stimulated murine BV2 microglia and injured brains induced by photothrombotic cortical ischemia. Hexane extracts of US (HEUS) significantly suppressed the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated BV2 microglia and inhibited LPS-induced expression of iNOS and COX-2 in a dose-dependent manner without causing cytotoxicity in BV2 cells. In addition, HEUS significantly reduced the generation of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6. Moreover, HEUS treatment inhibited the transcriptional activity and nuclear translocation of NF-κB in LPS-stimulated BV2 cells. In an in vivo study, treatment of HEUS resulted in significantly reduced infarct volume and improved neurological function 48 h after ischemic brain injury, possibly through the inhibition of the production of pro-inflammatory cytokines. HEUS inhibits LPS-stimulated production of pro-inflammatory mediators and prevents cerebral ischemic damage, suggesting that US may have therapeutic potential for the prevention and treatment of ischemic stroke accompanied by microglia activation.

Partially purified components of Uncaria sinensis attenuate blood brain barrier disruption after ischemic brain injury in mice

Background

Uncaria sinensis (US) has long been used in traditional Korean medicine to relieve various nervous-related symptoms and cardiovascular disease. We recently showed the neuroprotective and cerebrovascular protective effects of US on cerebral ischemia; however, its effects on the blood–brain barrier (BBB) are poorly understood. In this study, the effects of partially purified components of US (PPUS) on BBB disruption were investigated in mice subjected to ischemic brain injury.

Methods

Focal cerebral ischemia was induced in C57BL/6J mice by photothrombotic cortical ischemia. PPUS was injected intraperitoneally 30 min before ischemic insults. Infarct volume, neurological score, wire-grip test, Evans blue leakage and brain water content were then examined 24 h after ischemic brain injury.

Results

Infarct volume was significantly reduced and neurological deficit and motor deficit were greatly improved in PPUS-pretreated mice relative to those treated with vehicle following photothrombotic cortical ischemia. Brain edema-induced change of Evans blue extravasation and water content in the ipsilateral hemisphere were alleviated by treatment with PPUS. In addition, PPUS significantly reduced ischemic brain injury-induced degradation of tight junction proteins and elevation of matrix metalloproteinase-9 (MMP-9).

Conclusions

PPUS prevents cerebral ischemic damage by BBB protection, and these effects were associated with inhibition of tight junction degradation and MMP-9 induction.

Review of plants and their constituents in the therapy of cerebral ischemia

Cerebral ischemia is a condition in which there is insufficient blood flow to the brain to meet metabolic demand. This leads to cerebral hypoxia and thus to the death of neuronal cells or stroke. The limited number of medicines currently available for patients following ischemic stroke and insufficient data on efficiency of these chemicals in the treatment of stroke led us to the search for novel therapeutic approaches. Recent studies have focused on the possible capacity of natural compounds extracted from vegetables and fruits, to prevent human disabilities caused by cerebral ischemia. In this review, we will discuss some plants and their constituents that may protect brain ischemia or delay the neurological disorders following a stroke. We have reviewed different studies in scientific databases that investigate herbal compounds and their effects on cerebral ischemia.

Protective effect of hexane extracts of Uncaria sinensis against photothrombotic ischemic injury in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Uncaria sinensis (US) has been used in traditional Korean medicine to treat vascular disease and to relieve various neurological symptoms.

AIM OF THE STUDY

Scientific evidence related to the effectiveness or action mechanism of US on cerebrovascular disease has not been examined experimentally. Here, we investigated the cerebrovascular protective effect of US extracts on photothrombotic ischemic injury in mice.

MATERIALS AND METHODS

US hexane extracts (HEUS), ethyl acetate extracts (EAEUS) and methanol extracts (MEUS) were administered intraperitoneally 30 min before ischemic insults. Focal cerebral ischemia was induced in C57BL/6J mice and endothelial nitric oxide synthase knockout (eNOS KO) mice by photothrombotic cortical occlusion. We evaluated the infarct volume, neurological score and the activation of Akt and eNOS in ischemic brain.

RESULTS

HEUS more significantly reduced infarct volume and edema than did EAEUS and MEUS following photothrombotic cortical occlusion. HEUS produced decreased infarct volume and edema size, and improved neurological function in a concentration-dependent manner (10, 50, and 100 mg/kg). However, HEUS did not reduce brain infarction in eNOS KO mice, suggesting that the protective effect of HEUS is primarily endothelium-dependent. Furthermore, HEUS (10-300 μg/ml) produced a concentration-dependent relaxation in mouse aorta and rat basilar artery, which was not seen in eNOS KO mouse aorta, suggesting that HEUS cause vasodilation via an eNOS-dependent mechanism. This correlated with increased phosphorylation of Akt and eNOS in the brains of HEUS-treated mice.

CONCLUSION

HEUS prevent cerebral ischemic damage by regulating Akt/eNOS signaling. US, herbal medicine, may be the basis of a novel strategy for the therapy of stroke.

Taguchi approach for anti-heat stress prescription compatibility in mice spleen lymphocytes in vitro

Heat stress (HS) may induce immunosuppression as well as inhibit the proliferation of lymphocytes. This study evaluated the effects on immune function of our prescription on splenic lymphocytes under HS as well as its compatibility. The effects of four herbal extracts from Agastache rugosa, Atractylodes lancea, Cortex Phellodendri, and Gypsum Fibrosum on heat treated splenic lymphocytes were investigated and the compatibility of the prescription was also explored by using the Taguchi method. This study revealed changes in proliferation by traditional Chinese medicines of splenic lymphocytes after HS. Proliferation in the HS group was significantly lower than the control group. Under HS, the effects of higher concentrations of Agastache rugosa (100 and 200 μg/mL), Atractylodes lancea (100 and 200 μg/mL), Cortex Phellodendri (50 and 100 μg/mL) and Gypsum Fibrosum (100 and 200 μg/mL) caused a significant increase on ConA/LPS-induced proliferation of lymphocytes than lower concentrations. We, therefore, conclude that the prescription of traditional Chinese medicines may recover splenic lymphocytes from the immunosuppression induced by HS. The Taguchi design, which allows rapid and high efficiency for the selection of the best conditions for our prescription on HS-treated splenic lymphocytes, demonstrated that Agastache rugosa (200 μg/mL), Atractylodes lancea (200 μg/mL), Cortex Phellodendri (100 μg/mL) and Gypsum Fibrosum (100 μg/mL) were the optimal conditions for the prescription. The validation experiment confirmed that our composition in optimum extraction conditions enhanced effects on ConA or LPS-stimulated lymphocytes under HS. The results showed that the Taguchi optimization approach is a suitable method for optimization of the composition of prescription.

Neuroprotective effects of Yi-Gan San against beta amyloid-induced cytotoxicity on rat cortical neurons

INTRODUCTION

Recent clinical studies have demonstrated that Yi-Gan San (YGS, Yokukan-San in Japanese), a Chinese herbal medicine, alleviates various dementia-related symptoms. However, Chinese herbal medicines have rarely been investigated scientifically and the underlying mechanism of YGS remains uncertain. In this study, we investigated the effect of YGS on beta amyloid protein (Abeta)-induced cytotoxicity in a primary culture of rat cortical neurons.

METHODS

Cortical neurons prepared from rat embryos were exposed to Abeta in the presence or absence of YGS. The protective effect of YGS was measured as the % of control (unexposed neurons) by using MTT assay and LDH assay.

RESULTS

Abeta significantly decreased the number of surviving cortical neurons at a dose of 20 microM and higher. In the presence of 20 microM Abeta, YGS concentrations of 10(-5) g/L (W/V) and higher significantly increased the number of viable neurons.

CONCLUSION

Our study demonstrated a neuroprotective effect of Yi-Gan San against Abeta-induced cytotoxicity. Since according to traditional herbal medicine beliefs, YGS most likely exerts its clinical effects not through a single constituent but as a mixture of several herbal ingredients, the true mechanism of this neuroprotective action remains unclear. However, our results suggest that this Chinese herbal medicine might be a valuable treatment for clinical symptoms associated with dementia having fewer side effects and possible additional neuroprotective effects in the elderly.

Preventive effect of chotosan, a Kampo medicine, on transient ischemia-induced learning deficit is mediated by stimulation of muscarinic M1 but not nicotinic receptor

We have previously shown using a water maze task that transient 2 vessel occlusion (T2VO) induced learning deficit in mice and that the deficit was prevented by pre-treatment of mice with chotosan, a Kampo prescription. In this study, we investigated the mechanism underlying the preventive effect of chotosan on T2VO-induced learning deficit. Chotosan administration 1 h before T2VO operation prevented learning impairment. The extract of Uncaria, a major constituent of chotosan, also had a protective effect on learning impairment in T2VO mice, whereas Uncaria-free chotosan had no beneficial effect on maze performance of T2VO mice. The ameliorative effect of chotosan was blocked by pirenzepine, a muscarinic M1 antagonist, but not by mecamylamine, a nicotinic receptor antagonist. Acetylcholine (ACh) content in the hippocampus of T2VO mice was significantly lower than that in the hippocampus of sham-operated control mice. Chotosan and Uncaria administration attenuated T2VO-induced reduction of ACh levels in the brain. These results suggest that the preventive effect of chotosan on transient ischemia-induced learning impairment is mainly attributable to the effect of Uncaria and that the ameliorative effect is mediated by stimulation of muscarinic M1 receptor.

Uncaria rhynchophylla, a Chinese medicinal herb, has potent antiaggregation effects on Alzheimer's β-amyloid proteins

Because the deposition of beta-amyloid protein (Abeta) is a consistent pathological hallmark of Alzheimer's disease (AD) brains, inhibition of Abeta generation, prevention of Abeta fibril formation, or destabilization of preformed Abeta fibrils would be attractive therapeutic strategies for the treatment of AD. We examined the effects of several medicinal herbs used in traditional Chinese medical formulae on the formation and destabilization of Abeta fibrils by using the thioflavin T binding assay, atomic force microscopic imaging, and electrophoresis. Our study demonstrates that several of these herbs have potent inhibitory effects on fibril formation of both Abeta(1-40) and Abeta(1-42) in concentration-dependent manners; in particular, Uncaria rhynchophylla inhibited Abeta aggregation most intensively. Significant destabilization of preformed Abeta(1-40) and Abeta(1-42) fibrils was also induced by Uncaria rhynchophylla as well as some other herb extracts. Three-dimensional HPLC analysis indicated that the water extract of this herb contains several different chemical compounds, including oxindole and indol alkaloids, which have been regarded as neuroprotective. Our results suggest that Uncaria rhynchophylla has remarkably inhibitory effects on the regulation of Abeta fibrils, and we conclude that this medicinal herb could have the potency to be a novel therapeutic agent to prevent and/or cure AD.

Choto-san, a Kampo formula, improves chronic cerebral hypoperfusion-induced spatial learning deficit via stimulation of muscarinic M1 receptor

A recent double-blind and placebo-controlled study demonstrated a beneficial effect of Choto-san, a Kampo (traditional medicine of Japan) formula, on cognitive impairment in patients with vascular dementia. However, the neuronal mechanism underlying the therapeutic effects of this formula remains to be clarified. Using a chronic cerebral hypoperfusion model, we investigated the effect of Choto-san on cognitive dysfunction in mice to clarify its mechanism of actions. Chronic cerebral hypoperfusion was induced by permanent occlusion of both the common carotid arteries (2VO). Choto-san and Uncaria, a major constituent of Choto-san, caused an improvement in 2VO-induced learning deficits, whereas Uncaria-free Choto-san did not. The effects of Choto-san and Uncaria were blocked by pirenzepine, a selective muscarinic M1 antagonist. In a tube-dominance test, 2VO induced increased rates of assertive behavior in mice. 2VO mice administered Choto-san showed significantly reduced rates of assertive behavior compared to vehicle-treated controls, whereas Uncaria-free Choto-san and Uncaria had little effect on 2VO-induced assertive behavior. 2VO caused a significant decrease in the level of acetylcholine (ACh) contents in the brain, and the daily administration of Choto-san or Uncaria raised the ACh level to that in the sham-operated controls. These results suggest that Choto-san has an ameliorating effect on the spatial memory deficit caused by chronic hypoperfusion, and that the effect is mainly attributable to Uncaria. Moreover, it was suggested that the effects of Choto-san and Uncaria are at least partly mediated by stimulation of the muscarinic M1 receptor.

Effects of Choto-san and hooks and stems of Uncaria sinensis on antioxidant enzyme activities in the gerbil brain after transient forebrain ischemia

Previously, we revealed that oral administrations of Choto-san, a Kampo formula, and the hooks and stems of Uncaria sinensis Haviland (Rubiaceae), a medicinal plant comprising Choto-san, enhanced superoxide anion and hydroxyl radical scavenging activities in the hippocampus, and prevented delayed neuronal death of pyramidal cells in the hippocampal CA1 region in a transient forebrain ischemia gerbil model. In the present study, for the purpose of clarifying whether the endogenous antioxidant enzymes contribute to these mechanisms, we investigated the effects of Choto-san extract (CSE) and Uncaria sinensis extract (USE) on superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities in the brain by using the same experimental model. 1.0% CSE or 3.0% USE were dissolved in water and provided to gerbils ad libitum from 7 days prior to ischemia/reperfusion (i/rp). Seven days of continuous administrations of CSE or USE without i/rp procedure enhanced CAT activity but not SOD and GSH-Px activities in both the hippocampus and cortex. CSE elevated CAT activity in the hippocampus at 7 days and in the cortex at 3h after i/rp. USE raised CAT activity in both the hippocampus and cortex at 3 h and 7 days after i/rp. These results suggest that one of the mechanisms of the protective effects of CSE and USE against transient brain ischemia-induced neuronal damage may be their enhancing effect on CAT activity in the brain.