Protective effects of notoginsenoside R1 on cerebral ischemia-reperfusion injury in rats

Targeted Delivery of Macrophage Membrane Biomimetic Liposomes Through Intranasal Administration for Treatment of Ischemic Stroke

Purpose

Ginsenoside Rg3 (Rg3) and Panax notoginseng saponins (PNS) can be used for ischemic stroke treatment, however, the lack of targeting to the ischemic region limits the therapeutic effect. To address this, we leveraged the affinity of macrophage membrane proteins for inflamed brain microvascular endothelial cells to develop a macrophage membrane-cloaked liposome loaded with Rg3 and PNS (MM-Lip-Rg3/PNS), which can precisely target brain lesion region through intranasal administration.

Methods

MM-Lip-Rg3/PNS was prepared by co-extrusion method and was performed by characterization, stability, surface protein, and morphology. The cellular uptake, immune escape ability, and blood-brain barrier crossing ability of MM-Lip-Rg3/PNS were studied in vitro. The in vivo brain targeting, biodistribution and anti-ischemic efficacy of MM-Lip-Rg3/PNS were evaluated in MACO rats, and we determined the diversity of the nasal brain pathway through the olfactory nerve blockade model in rats. Finally, the pharmacokinetics and brain targeting index of MM-Lip-Rg3/PNS were investigated.

Results

Our results indicated that MM-Lip-Rg3/PNS was spherical with a shell-core structure. MM-Lip-Rg3/PNS can avoid mononuclear phagocytosis, actively bind to inflammatory endothelial cells, and have the ability to cross the blood-brain barrier. Moreover, MM-Lip-Rg3/PNS could specifically target ischemic sites, even microglia, increase the cumulative number of drugs in the brain, improve the inflammatory environment of the brain, and reduce the infarct size. By comparing olfactory nerve-blocking rats with normal rats, it was found that there are direct and indirect pathways for nasal entry into the brain. Pharmacokinetics demonstrated that MM-Lip-Rg3/PNS exhibited stronger brain targeting and prolonged drug half-life.

Conclusion

MM-Lip-Rg3/PNS might contribute to the accumulation of Rg3 and PNS in the ischemic brain area to improve treatment efficacy. This biomimetic nano-drug delivery system provides a new and promising strategy for the treatment of ischemic stroke.

Characterization of a novel thermophilic beta-glucosidase from Thermotoga sp. and its application in the transformation of notoginsenoside R1

A novel β-glucosidase (Thglu3) was identified from Thermotoga sp. which had biotransformation activity for notoginsenoside R1 (NR-R1). Sequence analysis of Thglu3 revealed that it could be classified into glycoside hydrolase family 3 (GH3). The gene encoding a 719-amino acid protein was cloned and expressed in Escherichia coli. The recombinant enzyme was purified, and its molecular weight was approximately 81 kDa. The recombinant Thglu3 exhibited an optimal activity at 75 °C and pH 6.4. The β-glucosidase had high selectivity for cleaving the outer glucose moiety at the C20 position of NR-R1, which produced the more pharmacologically active notoginsenoside R2 (NR-R2). Under the optimal reaction conditions for gram-scale production, 30 g NR-R1 was transformed to NR-R2 using 20 g crude enzyme at pH 6.4 and 75 °C within 1 h with a molar yield of 93%. This study was the first report of the highly efficient and selective gram-scale transformation of NR-R2 from NR-R1 by a thermophilic β-glucosidase.

Notoginsenoside R1 Regulates Ischemic Myocardial Lipid Metabolism by Activating the AKT/mTOR Signaling Pathway

Ischemic heart diseases are responsible for more than one-third of all deaths worldwide. Radix notoginseng is widely used to treat ischemic heart disease in China and other Asian countries, and notoginsenoside R1 (NGR1) is its characteristic and large-amount ingredient. However, the potential molecular mechanisms of NGR1 in improving ischemic heart diseases are unclear. In this study, we combined pharmacological evaluation with network pharmacology, myocardial proteomics, and conventional molecular dynamics (MD) simulation to explore the cardio-protection mechanisms of NGR1. Our results revealed that NGR1 improved the echocardiographic, tissue pathological, and serum biochemical perturbations in myocardial ischemic rats. The network pharmacology studies indicated that NGR1 mainly regulated smooth muscle cell proliferation, vasculature development, and lipid metabolism signaling, especially in the PI3K/AKT pathway. Myocardial proteomics revealed that the function of NGR1 was focused on regulating metabolic and energy supply processes. The research combined reverse-docked targets with differential proteins and demonstrated that NGR1 modulated lipid metabolism in ischemic myocardia by interacting with mTOR and AKT. Conventional MD simulation was applied to investigate the influence of NGR1 on the structural stabilization of the mTOR and AKT complex. The results suggested that NGR1 can strengthen the affinity stabilization of mTOR and AKT. Our study first revealed that NGR1 enhanced the affinity stabilization of mTOR and AKT, thus promoting the activation of the AKT/mTOR pathway and improving lipid metabolic abnormity in myocardial ischemic rats.

Preventing Dementia Using Saffron, The Kampo Medicine, Kamiuntanto, and Their Combination, Kamiuntantokabankoka

The objective of this review is to evaluate the anti-dementia activities of saffron and its combination with Kampo medicine. The Kampo formula Kamiuntanto composed of 13 crude drugs is well known for its anti-dementia activity. A significant increase in choline acetyltransferase activity and mRNA levels were observed. Polygala radix was identified as the most essential component drug in Kamiuntanto, probably due to the saponins, tenuifolin, and sinapinic acid. Ginseng was also identified as an essential Kamiuntanto component in terms of its synergistic functions with Polygala radix. Saffron, which was recommended in the Bencao Gangmu for memory and dementia, and is used as an anti-spasmodic, anti-catarrhal, and sedative herbal drug. Saffron and its major constituent, crocin were shown to enhance learning-memory, non-rapid eye movement (rem) sleep, and inhibit depression and neuronal cell death due to strong anti-oxidant and anti-inflammation activities. In addition based on the epidemiological studies such as the treatment of sleeping disorders and the clinical trials of saffron for Alzheimer patients, we demonstrated the indirect and direct anti-dementia activities of crocin and saffron.

The Protective Effect of Notoginsenoside R1 on Isoflurane-Induced Neurological Impairment in the Rats via Regulating miR-29a Expression and Neuroinflammation

INTRODUCTION

Isoflurane inhalation leads to apoptotic neurodegeneration and further results in learning and cognitive dysfunction. Notoginsenoside R1 (NGR1), a major ingredient from Radix notoginseng, has been reported to exert neuroprotective effect during brain or neuron injury. This study aimed to investigate the effect of NGR1 on neurological impairment.

METHODS

Sixty-four male Sprague Dawley rat pups (15-20 g) of postnatal day 7 were recruited. Spatial learning and memory were assessed by the Morris water maze test, and the neurological severity score was determined. Real-time quantitative PCR was used to detect the expression levels of microRNA (miR)-29a. Enzyme-linked immunosorbent assay was applied to estimate the levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in the hippocampal tissues.

RESULTS

NGR1 attenuated neurological impairment induced by isoflurane, shown by the decrease in neurological function score and escape latency and the increase in staying time in the original quadrant in rats. NGR1 reversed the downregulation of miR-29a expression induced by isoflurane treatment. After the treatment of NGR1, the elevated levels of IL-6, TNF-α, and IL-1β induced by isoflurane were all decreased significantly in the hippocampal tissues of rats. Additionally, the repressive action of NGR1 in neurological impairment and neuroinflammation was eliminated by downregulating miR-29a in rats.

CONCLUSION

NGR1 protects against isoflurane-induced neurological impairment. The protective effect of NGR1 might be achieved by promoting the expression of miR-29a and preventing inflammatory response.

Aloperine protects against cerebral ischemia/reperfusion injury via activating the PI3K/AKT signaling pathway in rats

Cerebral ischemia is among the leading causes of death and long-term disability worldwide. The aim of the present study was to investigate the effects of aloperine (ALO) on cerebral ischemia/reperfusion (I/R) injury in rats and elucidate the possible underlying mechanisms. Therefore, a rat model of reversible middle cerebral artery occlusion (MCAO) was established to induce cerebral I/R injury. Following pretreatment with different doses of ALO, the histopathological changes in the brain tissue were evaluated by hematoxylin and eosin staining. The degree of cerebral infarction was determined using by 2,3,5-triphenyltetrazolium chloride staining. Additionally, the levels of oxidative stress- and inflammation-related factors were measured using commercially available kits. Cell apoptosis was assessed by TUNEL staining, while the expression levels of apoptosis- and PI3K/AKT signaling pathway-related proteins were determined by western blot analysis. The results demonstrated that ALO alleviated histopathological injury in the brain tissue and the area of cerebral infarction in a dose-dependent manner. Furthermore, significantly reduced levels of reactive oxygen species and malondialdehyde were observed in the ALO-treated rats post-MCAO/reperfusion, accompanied by increased levels of superoxide dismutase, catalase and glutathione. Consistently, treatment with ALO notably decreased the concentration of inflammatory factors, including TNF-α, IL-1β and IL-6, in a dose-dependent manner. In addition, ALO attenuated neuronal cell apoptosis, downregulated the expression of Bax and upregulated that of Bcl-2. I/R markedly reduced the expression levels of phosphorylated (p-)PI3K and p-AKT, which were dose-dependently restored by ALO intervention. Collectively, the aforementioned findings indicated that ALO could improve cerebral I/R injury and alleviate oxidative stress, inflammation and cell apoptosis via activating the PI3K/AKT signaling pathway, thus supporting the therapeutic potential of ALO against cerebral I/R injury in ischemic stroke.

Notoginsenoside R1 Improves Cerebral Ischemia/Reperfusion Injury by Promoting Neurogenesis via the BDNF/Akt/CREB Pathway

Notoginsenoside R1 (R1), a major component isolated from P. notoginseng, is a phytoestrogen that exerts many neuroprotective effects in a rat model of ischemic stroke. However, its long-term effects on neurogenesis and neurological restoration after ischemic stroke have not been investigated. The aim of this study was to evaluate the effects of R1 on neurogenesis and long-term functional recovery after ischemic stroke. We used male Sprague-Dawley rats subjected to middle cerebral artery occlusion/reperfusion (MCAO/R). R1 was administered by intraperitoneal (i.p.) injection immediately postischemia. We showed that R1 significantly decreased infarct volume and neuronal loss, restored neurological function, and stimulated neurogenesis and oligodendrogenesis in rats subjected to MCAO/R. More importantly, R1 promoted neuronal proliferation in PC12 cells in vitro. The proneurogenic effects of R1 were associated with the activation of Akt/cAMP responsive element-binding protein, as shown by the R1-induced increase in brain-derived neurotrophic factor (BDNF) expression, and with the activation of neurological function, which was partially eliminated by selective inhibitors of BDNF and PI3K. We demonstrated that R1 is a promising compound that exerts neuroprotective and proneurogenic effects, possibly via the activation of BDNF/Akt/CREB signaling. These findings offer insight into exploring new mechanisms in long-term functional recovery after R1 treatment of ischemic stroke.

Notoginsenoside R1 counteracts mesenchymal stem cell-evoked oncogenesis and doxorubicin resistance in osteosarcoma cells by blocking IL-6 secretion-induced JAK2/STAT3 signaling

Tumor microenvironment is a critical participant in the initiation, progression and drug resistance of carcinomas, including osteosarcoma. Notoginsenoside R1 (NGR1) is a proverbial active ingredient of the traditional Chinese medicine Panax notoginseng (PN) and possess undeniable roles in several cancers. Nevertheless, its function in osteosarcoma and tumor microenvironment remains elusive. In the current study, exposure to NGR1 dose-dependently inhibited osteosarcoma cell viability and migration, and induced apoptosis. Furthermore, osteosarcoma cells that were incubated with conditioned medium (CM) from bone marrow mesenchymal stem cells (BMSCs) exhibited greater proliferation, migration capacity and MMP-2 and MMP-9 expression relative to control cells, which was reversed when BMSCs were treated with NGR1. Notably, administration with NGR1 antagonized CM-evoked doxorubicin resistance in osteosarcoma cells by decreasing cell viability and increasing cell apoptosis and caspase-3/9 activity. Mechanically, NGR1 suppressed IL-6 secretion from BMSCs, as well as the subsequent activation of the JAK2/STAT3 signaling in osteosarcoma cells. In addition, blocking the JAK2 pathway by its antagonist AG490 reversed CM-induced osteosarcoma cell proliferation, migration and doxorubicin resistance. Moreover, exogenous supplementation with IL-6 engendered not only the reactivation of the JAK2/STAT3 signaling but also muted NGR1-mediated efficacy against osteosarcoma cell malignancy and doxorubicin resistance. Collectively, NGR1 may directly restrain osteosarcoma cell growth and migration, or indirectly antagonize MSC-evoked malignancy and drug resistance by interdicting IL-6 secretion-evoked activation of the JAK2/STAT3 pathway. Consequently, the current study may highlight a promising therapeutic strategy against osteosarcoma by regulating tumor cells and the tumor microenvironment.

Focus on Notoginsenoside R1 in Metabolism and Prevention Against Human Diseases

Notoginsenoside (NG)-R1 is one of the main bioactive compounds from Panax notoginseng (PN) root, which is well known in the prescription for mediating the micro-circulatory hemostasis in human. In this article, we mainly discuss NG-R1 in metabolism and the biological activities, including cardiovascular protection, neuro-protection, anti-diabetes, liver protection, gastrointestinal protection, lung protection, bone metabolism regulation, renal protection, and anti-cancer. The metabolites produced by deglycosylation of NG-R1 exhibit higher permeability and bioavailability. It has been extensively verified that NG-R1 may ameliorate ischemia-reperfusion (IR)-induced injury in cardiovascular and neuronal systems mainly by upregulating the activity of estrogen receptor α-dependent phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) and nuclear factor erythroid-2-related factor 2 (NRF2) pathways and downregulating nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. However, no specific targets for NG-R1 have been identified. Expectedly, NG-R1 has been used as a main bioactive compound in many Traditional Chinese Medicines clinically, such as Xuesaitong, Naodesheng, XueShuanTong, ShenMai, and QSYQ. These suggest that NG-R1 exhibits a significant potency in drug development.

Involvement of apoptosis in the protective effects of Dracocephalum moldavaica in cerebral ischemia reperfusion rat model

An extract of Dracocephalum moldevica (DML) was found to exert protective effects on cerebral ischemia-reperfusion injury (CIRI); however, the mechanisms underlying the observed actions of this plant-derived mixture remain to be determined. Thus, the aim of this study was to examine the influence of DML on CIRI rat model induced by middle cerebral artery occlusion (MCAO). The following parameters were measured: (1) viable neurons in the infarcted area using Nissl staining; and (2) immunohistochemistry and Western blot were employed to determine protein expression levels of p53, bcl-2 associated X protein (bax) and B-cell lymphoma-2 (bcl-2), three biomarkers of apoptosis. MCAO significantly decreased the number of viable cortical pyramidal neurons in the infarcted area, while treatment with DML extract significantly elevated the number of viable neurons. MCAO was found to significantly elevate in gene expression levels of p53 and protein expression levels bax accompanied by diminished protein expression levels of bcl-2. Prior administration of DML extract produced marked reduction in gene expression levels of p53 and protein expression levels bax but increased in protein expression levels of bcl-2. Data suggested apoptosis was initiated in MCAO and that DML was effective in treating CIRI via an anti-apoptotic action as evidenced by inhibition of gene expression levels of p53 and protein expression levels of bax with concomitant elevation in protein expression levels of bcl-2. Our findings suggest that extract of DML may prove beneficial in treatment of cerebrovascular disorders.

Notoginsenoside R1 for Organs Ischemia/Reperfusion Injury: A Preclinical Systematic Review

Notoginsenoside R1 (NGR1) exerts pharmacological actions for a variety of diseases such as myocardial infarction, ischemic stroke, acute renal injury, and intestinal injury. Here, we conducted a preclinical systematic review of NGR1 for ischemia reperfusion (I/R) injury. Eight databases were searched from their inception to February 23rd, 2019; Review Manager 5.3 was applied for data analysis. CAMARADES 10-item checklist and cell 10-item checklist were used to evaluate the methodological quality. Twenty-five studies with 304 animals and 124 cells were selected. Scores of the risk of bias in animal studies ranged from 3 to 8, and the cell studies ranged from 3 to 5. NGR1 had significant effects on decreasing myocardial infarct size in myocardial I/R injury, decreasing cerebral infarction volume and neurologic deficit score in cerebral I/R injury, decreasing serum creatinine in renal I/R injury, and decreasing Park/Chiu score in intestinal I/R injury compared with controls (all P < 0.05 or P < 0.01). The multiple organ protection of NGR1 after I/R injury is mainly through the mechanisms of antioxidant, anti-apoptosis, and anti-inflammatory, promoting angiogenesis and improving energy metabolism. The findings showed the organ protection effect of NGR1 after I/R injury, and NGR1 can potentially become a novel drug candidate for ischemic diseases. Further translation studies are needed.

Enzymatic Synthesis of Unnatural Ginsenosides Using a Promiscuous UDP-Glucosyltransferase from Bacillus subtilis

Glycosylation, which is catalyzed by UDP-glycosyltransferases (UGTs), is an important biological modification for the structural and functional diversity of ginsenosides. In this study, the promiscuous UGT109A1 from Bacillus subtilis was used to synthesize unnatural ginsenosides from natural ginsenosides. UGT109A1 was heterologously expressed in Escherichia coli and then purified by Ni-NTA affinity chromatography. Ginsenosides Re, Rf, Rh1, and R1 were selected as the substrates to produce the corresponding derivatives by the recombinant UGT109A1. The results showed that UGT109A1 could transfer a glucosyl moiety to C3-OH of ginsenosides Re and R1, and C3-OH and C12-OH of ginsenosides Rf and Rh1, respectively, to produce unnatural ginsenosides 3,20-di-O-β-d-glucopyranosyl-6-O-[α-l-rhamnopyrano-(1→2)-β-d-glucopyranosyl]-dammar-24-ene-3β,6α,12β,20S-tetraol (1), 3,20-di-O-β-d-glucopyranosyl-6-O-[β-d-xylopyranosyl-(1→2)-β-d-glucopyranosyl]-dammar-24-ene-3β,6α,12β,20S-tetraol (6), 3-O-β-d-glucopyranosyl-6-O-[β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl]-dammar-24-ene-3β,6α,12β,20S-tetraol (3), 3,12-di-O-β-d-glucopyranosyl-6-O-[β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl]-dammar-24-ene-3β,6α,12β,20S-tetraol (2), 3,6-di-O-β-d-glucopyranosyl-dammar-24-ene-3β,6α,12β,20S-tetraol (5), and 3,6,12-tri-O-β-d-glucopyranosyl-dammar-24-ene-3β,6α,12β,20S-tetraol (4). Among the above products, 1, 2, 3, and 6 are new compounds. The maximal activity of UGT109A1 was achieved at the temperature of 40 °C, in the pH range of 8.0⁻10.0. The activity of UGT109A1 was considerably enhanced by Mg2+, Mn2+, and Ca2+, but was obviously reduced by Cu2+, Co2+, and Zn2+. The study demonstrated that UGT109A1 was effective in producing a series of unnatural ginsenosides through enzymatic reactions, which could pave a way to generate promising leads for new drug discovery.

Modulation of brain ACE and ACE2 may be a promising protective strategy against cerebral ischemia/reperfusion injury: an experimental trial in rats

The brain renin-angiotensin system (RAS) is considered a crucial regulator for physiological homeostasis and disease progression. We evaluated the protective effects of the angiotensin receptor blocker (ARB) telmisartan and the angiotensin-converting enzyme 2 (ACE2) activator xanthenone on experimental cerebral ischemia/reperfusion (I/R) injury. Rats were divided into a sham control, a cerebral I/R control, a standard treatment (nimodipine, 10 mg/kg/day, 15 days, p.o.), three telmisartan treatments (1, 3, and 10 mg/kg/day, 15 days, p.o.), and three xanthenone treatments (0.5, 1, and 2 mg/kg/day, 15 days, s.c.) groups. One hour after the last dose, all rats except the sham control group were exposed to 30-min cerebral ischemia followed by 24-h reperfusion. Brain ACE and ACE2 activities and the apoptotic marker caspase-3 levels were assessed. Glutathione (GSH), malondialdehyde (MDA), and nitric oxide end products (NOx) as oxidative markers and tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and IL-10 as immunological markers were assessed. Histopathological examination and immunohistochemical evaluation of glial fibrillary acidic protein (GFAP) were performed in cerebral cortex and hippocampus sections. Telmisartan and xanthenone in the higher doses restored MDA, NOx, TNF-α, IL-6, caspase-3, ACE, and GFAP back to normal levels and significantly increased GSH, IL-10, and ACE2 compared to I/R control values. Histopathologically, both agents showed mild degenerative changes and necrosis of neurons in cerebral cortex and hippocampus compared with I/R control group. Modulation of brain RAS, either through suppression of the classic ACE pathway or stimulation of its antagonist pathway ACE2, may be a promising strategy against cerebral I/R damage.