[Interventional treatment of symptomatic intracranial in-stent restenosis]

Objective: To assess the feasibility and safety of interventional treatment of symptomatic intracranial in-stent restenosis (SISR). Methods: Clinical data of 21 patients with SISR who underwent interventional treatment in the General Hospital of the PLA Rocket Force from January 2012 to May 2018 were retrospectively analyzed. Perioperative complications, angiographic and clinical follow-up results were recorded. Results: The success rate of treatment was 100%, including 21 lesions of SISR (7 at the V4 segment of the vertebral artery, 7 at the basilar artery, 5 at the M1 segment of middle cerebral artery, 2 at the internal carotid artery). The residual stenosis rate was preoperative 84±7, postoperative 30±14 respectively. Balloon angioplasty and stent implantation were performed in 10 patients (48.6%) and 11 patients (52.4%), respectively. After treatment, 1 patient experienced perforating event without neurological sequelae. Of the 11 patients (52.4%) completed angiography follow-up, 3 (3/11, 27.3%) ocurred restenosis and 1 was retreated. During clinical follow-up, 1 patients received intravenous thrombolysis for the symptom of acute cerebral infarction in territory of stenting artery, in-stent restenosis or occlusion was not demonstrated by emergency cerebral angiography. Conclusion: Interventional treatment of SISR is feasible and safe, however, further studies need to warrant the long-term effects.

Discovery of natural flavonoids as activators of Nrf2-mediated defense system: Structure-activity relationship and inhibition of intracellular oxidative insults

Continuous overproduction of reactive oxygen species (ROS), termed as oxidative stress, plays a crucial role in the onset and progression of many human diseases. Activation of nuclear transcription factor erythroid 2-related factor (Nrf2) by small molecules could eliminate ROS, and thus block the pathogenesis of oxidative stress-induced diseases. In this study, a natural flavonoid library was established and tested for their potential Nrf2 inducing effects. Based on QR inducing effect of flavonoids, their structure-activity relationship (SAR) on Nrf2 induction was summarized, and twenty flavonoids were firstly identified to be potential activators of Nrf2-mediated defensive response. Then, 7-O-methylbiochanin A (7-MBA) was further investigated for its capability on the Nrf2 activation and prevention against oxidative insults in human lung epithelial cells. Further studies indicated that 7-MBA activated Nrf2 signaling pathway and protected human lung epithelial Beas-2B cells against sodium arsenite [As(III)]-induced cytotoxicity in an Nrf2-dependent manner. Activation of Nrf2 by 7-MBA upregulated intracellular antioxidant capacity, which was produced by enhancement of Nrf2 stabilization, blockage of Nrf2 ubiquitination, as well as Nrf2 phosphorylation by mitogen-activated protein kinase (MAPK), protein kinase C (PKC), protein kinase R-like endoplasmic reticulum kinase (PERK), and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K). Taken together, 7-MBA is a novel isoflavone-type Nrf2 activator displaying potential preventive effect against oxidative damages in human lung epithelial cells.

Identification of an Asexual Reproduction Inducer of Phytopathogenic and Toxigenic Fusarium

Asexual and sexual reproduction are the most important biological events in the life cycle of phytopathogenic and toxigenic Fusarium and are responsible for disease epidemics. However, the signaling molecules which induce the asexual reproduction of Fusarium are unknown. Herein we describe the structure elucidation, including the absolute configuration, of Fusarium asexual reproduction inducer (FARI), a new sesquiterpene derivative, by spectroscopic analysis, total synthesis, and conidium-inducing assays of synthetic isomers. We have also uncovered the universality of FARI among Fusarium species. Moreover, a mechanism-of-action study suggested that the Gpmk1 and LaeA signaling pathways are required for conidium formation induced by FARI; conversely, the Mgv1 of mitogen-activated protein kinase is not involved in conidium formation. FARI exhibited conidium-inducing activity at an extremely low dose and high stereoselectivity, which may suggest the presence of a stereospecific target.

3D Architectured Graphene/Metal Oxide Hybrids for Gas Sensors: A Review

Graphene/metal oxide-based materials have been demonstrated as promising candidates for gas sensing applications due to the enhanced sensing performance and synergetic effects of the two components. Plenty of metal oxides such as SnO₂, ZnO, WO₃, etc. have been hybridized with graphene to improve the gas sensing properties. However, graphene/metal oxide nanohybrid- based gas sensors still have several limitations in practical application such as the insufficient sensitivity and response rate, and long recovery time in some cases. To achieve higher sensing performances of graphene/metal oxides nanocomposites, many recent efforts have been devoted to the controllable synthesis of 3D graphene/metal oxides architectures owing to their large surface area and well-organized structure for the enhanced gas adsorption/diffusion on sensing films. This review summarizes recent advances in the synthesis, assembly, and applications of 3D architectured graphene/metal oxide hybrids for gas sensing.

Bioactivity-guided isolation of neuritogenic triterpenoids from the leaves of Ilex latifolia Thunb

Ilex latifolia Thunb is a traditional Chinese tea and herbal medicine. In this study, one new triterpene saponin (1) and six known triterpenoids (2-7) were isolated from the methanol extract of I. latifolia using a PC12 cell bioassay system. The structures and stereochemistry of these compounds were elucidated using spectroscopic methods and chemical derivatization. This new triterpene saponin (1) was characterized as an ursolic type acid with a 19α-hydroxyl and a trisaccharide moiety at C-3. Compound 1 significantly promoted the neurite outgrowth in PC12 cells by 52% at 10 μM, whereas compounds 2-7 showed less neuritogenic activity. Structure activity relationship studies indicated that introducing a trisaccharide moiety at C-3 is important for the neuritogenic activity, but the sugar group at C-28 decreased this activity. In addition, compound 1 increased the neurite outgrowth length in primary cortical neuron cells of mice and also exhibited a neuronal protection effect on H₂O₂-damaged PC12 cells at optimum concentrations.

A New Anti-Aging Lysophosphatidic Acid from Arabidopsis thaliana

BACKGROUND

Aging is a risk factor of age-related diseases. With the increasing number of patients, serious consequences, and heavy economic burden, demands for drugs used to treat agerelated diseases have increased. As such, anti-aging substances should be isolated to develop drugs for the prevention and treatment of age-related diseases.

METHOD

In this study, a methanol extract of immature Arabidopsis thaliana seeds with coat was separated by using a K6001 yeast bioassay system. In order to investigate the action mechanism, four mutants, namely, Δuth1, Δskn7, Δsod1, and Δsod2 with K6001 background were employed and the anti-oxidative stress assay was performed.

RESULTS

One new anti-aging lysophosphatidic acid (LPA) was obtained, and its structural and stereochemical characteristics were elucidated through spectroscopy and chemical derivatization. LPA can extend the replicative lifespan of K6001 at 10 and 30 µM (p < 0.001 and p < 0.01, respectively). This finding was comparable to the effect of resveratrol, a well-known anti-aging substance. However, the anti-aging activity of the compound on the four mutants was diminished. In the antioxidative stress assay, LPA improved the oxidative resistance of yeast cells.

CONCLUSION

The new LPA may exert its anti-aging effect by improving the anti-oxidative ability of yeast cells. The genes of UTH1, SKN7, and SOD may also be involved in the action.

Tetradecyl 2,3-Dihydroxybenzoate Improves the Symptoms of Diabetic Mice by Modulation of Insulin and Adiponectin Signaling Pathways

Background: Tetradecyl 2,3-dihydroxybenzoate (ABG-001) derived from Chinese medicine, gentiana regescens Franch is a leading compound with NGF mimic effect, it can induce neurite outgrowth of PC12 cells via the IGF-1/PI3K/ERK signaling pathway. Thus, we inferred that this compound had anti-diabetic effect and used streptozocin (STZ)-induced diabetic mice to indicate it. Methods: ABG-001 was synthesized with 2,3-dihydroxybenzoic acid and tetradecyl alcohol under certain reaction conditions. STZ-induced diabetic mice were used to investigate anti-diabetic effect. Oral glucose tolerance test, insulin tolerance test, RT-PCR, Western blot, ELISA assays and histological section were performed to do the analysis of action mechanism. Results: ABG-001 showed anti-diabetic effect in STZ-induced diabetic mice. In diabetic mice, the anti-diabetic effect of ABG-001 at a dose of 20 mg/kg was equal with metformin at a dose of 140 mg/kg. Moreover, glucose tolerance and insulin sensitivity were significantly improved on diabetic mice. The plasma insulin, adiponectin and leptin were notably increased, whereas glucagon remarkably decreased. The gene expressions of adiponectin and leptin in adipose tissue, glucose transporter 4 and adiponectin receptor 1 in liver and gastrocnemius, ADR2 in hypothalamus and pancreas were obviously increased. Conclusion: ABG-001 exerts antidiabetic effects via modulation of insulin and adiponectin signaling pathways. This new type of molecule could be a promising drug candidate for treatment of diabetes.

Flexible room-temperature formaldehyde sensors based on rGO film and rGo/MoS2 hybrid film

Gas sensors based on reduced graphene oxide (rGO) films and rGO/MoS₂ hybrid films were fabricated on polyethylene naphthalate substrates by a simple self-assembly method, which yielded flexible devices for detection of formaldehyde (HCHO) at room temperature. The sensing test results indicated that the rGO and rGO/MoS₂ sensors were highly sensitive and fully recoverable to a ppm-level of HCHO. The bending and fatigue test results revealed that the sensors were also mechanically robust, durable and effective for long-term use. The rGO/MoS₂ sensors showed higher sensitivities than rGO sensors, which was attributed to the enhanced HCHO adsorption and electron transfer mediated by MoS₂. Furthermore, two kinds of MoS₂ nanosheets were prepared by either hydrothermal synthesis or chemical exfoliation and were compared for their detection of HCHO, which revealed that the hydrothermally produced MoS₂ nanosheets with rich defects led to enhanced sensitivity of the rGO/MoS₂ sensors. Moreover, these fabricated flexible sensors can be applied for the HCHO detection in food packaging.

Efficient and Reversible Electron Doping of Semiconductor-Enriched Single-Walled Carbon Nanotubes by Using Decamethylcobaltocene

Single-walled carbon nanotubes (SWCNTs) offer great potential for field-effect transistors and integrated circuit applications due to their extraordinary electrical properties. To date, as-made SWCNT transistors are usually p-type in air, and it still remains challenging for realizing n-type devices. Herein, we present efficient and reversible electron doping of semiconductor-enriched single-walled carbon nanotubes (s-SWCNTs) by firstly utilizing decamethylcobaltocene (DMC) deposited by a simple spin-coating process at room temperature as an electron donor. A n-type transistor behavior with high on current, large I _on /I _off ratio and excellent uniformity is obtained by surface charge transfer from the electron donor DMC to acceptor s-SWCNTs, which is further corroborated by the Raman spectra and the ab initio simulation results. The DMC dopant molecules could be reversibly removed by immersion in N, N-Dimethylformamide solvent, indicating its reversibility and providing another way to control the carrier concentration effectively as well as selective removal of surface dopants on demand. Furthermore, the n-type behaviors including threshold voltage, on current, field-effect mobility, contact resistances, etc. are well controllable by adjusting the surface doping concentration. This work paves the way to explore and obtain high-performance n-type nanotubes for future complementary CMOS circuit and system applications.

Leptin Gene Transfer Improves Symptoms of Type 2 Diabetic Mice by Regulating Leptin Signaling Pathway and Insulin Resistance of Peripheral Tissues

The leptin gene was transferred into the liver of streptozocin- and high fat diet-induced type 2 diabetic (T2D) mice by hydrodynamic-based gene delivery. The food intake, water consumption, glucose concentration, and triglyceride and total cholesterol levels of T2D mice were significantly decreased. Meanwhile, plasma leptin was remarkably increased after gene transfer for 2, 3, 5, and 7 days, while plasma adiponectin was also significantly increased at day 2. To understand the mechanism of action of leptin on T2D mice, gene expressions related to glycometabolism and energy metabolism in the liver, epididymal adipose tissue, hypothalamus, and muscle were measured. The mRNA expression levels of adiponectin receptor 1 (ADR1), glucose transporter 4 (GLUT4), glucose-6-phosphase, and peroxisome proliferator-activated receptor γ in the liver, leptin, adiponectin, and hormone-sensitive lipase in adipose tissue, leptin, leptin-receptor, ADR1 in the hypothalamus, and ADR1, GLUT4, and insulin 1 in the gastrocnemius significantly increased. Moreover, the hepatic glycogen of the leptin-gene-treated group was significantly increased in comparison to the control group. Meanwhile, the significant decrease of forkhead box O1, adiponectin receptor 2, and peroxisome proliferator-activated receptor α in the liver, and agouti-related protein and proopiomelanocortin genes in the hypothalamus were also observed. In fat tissue and hypothalamus, leptin and adiponectin protein levels were also significantly increased, whereas the neuropeptide Y protein level was significantly decreased. These results indicated that the leptin gene transfer could improve the symptoms of T2D mice by regulating the leptin-hypothalamus signaling pathway and improving the insulin resistance of the peripheral tissues of T2D mice.

Sesquiterpene glucosides from Shenzhou honey peach fruit showed the anti-aging activity in the evaluation system using yeasts

One new (1, SZMT01) and one known (2) anti-aging substances were isolated from Shenzhou honey peach fruit. Their structures were elucidated by spectroscopic methods and chemical derivatization, and the result reveals that these two compounds are sesquiterpene glucosides. SZMT01 possesses a new glycosylation with an ester linkage at one terminal in an acyclic sesquiterpenoid which is the end of a double bond at another terminal. Both compounds extend the replicative lifespan of K6001 yeast strain at doses of 7.5 and 25 μM. Then, to understand the action mechanism involved, we performed an anti-oxidative experiment on SZMT01. The result revealed that treatment with SZMT01 increased the survival rate of yeast under oxidative stress. Moreover, the lifespans of sod1 and sod2 mutant yeast strains with a K6001 background were not affected by SZMT01. These results demonstrate that anti-oxidative stress performs important roles in anti-aging effects of SZMT01.

Protective effect of a phenolic extract containing indoline amides from Portulaca oleracea against cognitive impairment in senescent mice induced by large dose of D-galactose /NaNO2

ETHNOPHARMACOLOGICAL RELEVANCE

Portulaca oleracea L. is a potherb and also a widely used traditional Chinese medicine. In accordance with its nickname "longevity vegetable", pharmacological study demonstrated that this plant possessed antioxidant, anti-aging, and cognition-improvement function. Active principles pertaining to these functions of P. oleracea need to be elucidated.

AIM OF THE STUDY

The present study evaluated the effect of a phenolic extract (PAAs) from P. oleracea which contained specific antioxidant indoline amides on cognitive impairment in senescent mice.

MATERIALS AND METHODS

PAAs was prepared through AB-8 macroporous resin column chromatography. Total phenol content was determined using colorimetric method, and contents of indoline amides were determined using HPLC-UV method. Senescent Kunming mice with cognitive dysfunction were established by intraperitoneal injection of D-galactose (D-gal, 1250mg/kg/day) and NaNO₂ (90mg/kg/day) for 8 weeks, L-PAAs (360mg/kg/day), H-PAAs (720mg/kg/day), and nootropic drug piracetam (PA, 400mg/kg/day) as the positive control were orally administered. Spatial learning and memory abilities were evaluated by Morris water maze experiment. Activities of AChE, SOD, CAT, and levels of GSH and MDA in the brain or plasma were measured. Hippocampal morphology was observed by HE staining.

RESULTS

Chronic treatment of large dose of D-gal/NaNO₂ significantly reduced lifespan, elevated AChE activity, decreased CAT activity, compensatorily up-regulated SOD activity and GSH level, increased MDA level, induced neuronal damage in hippocampal CA1, CA3 and CA4 regions, and impaired cognitive function. Similar to PA, PAAs prolonged the lifespan and improved spatial memory ability. Moreover, PAAs improved learning ability. H-PAAs significantly reversed compensatory increase in SOD activity to the normal level, elevated serum CAT activity, and reduced MDA levels in brain and plasma, more potent than L-PAAs. Besides these, PAAs evidently inhibited hippocampal neuronal damage. However, it had no effect on brain AChE activity.

CONCLUSION

PAAs as the bioactive principles of P. oleracea attenuated oxidative stress, improved survival rate, and enhanced cognitive function in D-gal/NaNO₂-induced senile mice, similar to piracetam. This phenolic extract provides a promising candidate for prevention of aging and aging-related cognitive dysfunction in clinic.

Sodiation-based in-source collision for profiling of pyranocoumarins in Radix Peucedani (Qianhu): utility of sodium adducts' stability with in-source collision

Full scan mode of liquid chromatography-mass spectrometry equipped with an electrospray ionization source offers a chance on global detection of complicated components; however, the scan mode carries significant challenges in rapidly capturing information of analysts. Sodiation-based in-source collision was proposed here, as a technique for rapid detecting untargeted analytes in full scan analysis, which was based on the stability of sodium adducts and the nonselectivity of in-source collision. Then the technique was applied to profile of angular-type pyranocoumarins (APs) in Radix Peucedani, with full scan analysis performed at two specific in-source collision energy: a high energy 50 V that is tolerated by the sodium adducts of APs, and a low energy 10 V, at which abundant adducts were offered. The spectra list of two average mass spectra was exported, and stable ions were selected based on the intensity ratio of standards at the two collision energy. Then 27 plausible [M + Na]⁺ m/z values of APs were acquired after filtering the fragment ion and isotope ions and validating with [M + NH₄ ]⁺ . Eighty-two APs finally were tentatively identified based on their accurate spectral data of MSⁿ , fragmentation rules, and elution order regardless of their absolute configuration, which included 25 reported APs from Peucedanum praeruptorum Dunn. The technique provided a novel application of sodium adduct in qualitative analysis. And it was valuable for rapidly capturing information of analytes in full scan analysis, not only for APs but also for other compounds that could form sodium adducts. Copyright © 2017 John Wiley & Sons, Ltd.

Effect of Oleracein E, a Neuroprotective Tetrahydroisoquinoline, on Rotenone-Induced Parkinson's Disease Cell and Animal Models

Oleracein E (OE), a tetrahydroisoquinoline possessing potent antioxidant activity, was first isolated from a traditional Chinese medicine, Portulaca oleraea L., and is hypothesized to be a neuroprotectant. In the present study, we evaluated the effects of racemic OE on rotenone-induced toxicity in Parkinson's disease (PD) cell and animal models. Pretreatment with OE (10 μM, 2 h) decreased lactic acid dehydrogenase (LDH) release and the apoptosis rate in rotenone (5 μM, 24 h)-treated SH-SY5Y human neuroblastoma cells. Further mechanistic study indicated that OE reduced reactive oxygen species (ROS) levels, inhibited extracellular signal-regulated kinase (ERK) 1/2 phosphorylation, reduced rotenone-induced up-regulation of the proapoptotic protein Bax, and prevented cytochrome C release and caspase-3 activation. In a rotenone-treated (intragastric 30 mg/(kg·d), 56 d) C57BL-6J mouse model, OE (intragastric 15 mg/(kg·d), 56 d) improved motor function, as indicated by an increased moving distance in the spontaneous activity test and sustained time on the rota-rod test. OE also elevated superoxide dismutase (SOD) activity, decreased malonaldehyde content, and reduced ERK1/2 phosphorylation in the midbrain and striatum of mice treated with rotenone. Furthermore, OE preserved tyrosine hydroxylase-positive neurons and maintained the density of dopaminergic (DAergic) fibers in the substantia nigra pars compacta (SNpc). Some of the effects of OE on PD models were similar to those of the positive control selegiline hydrochloride. Our results demonstrated that OE protects DAergic neurons against rotenone toxicity through reducing oxidative stress and down-regulating stress-related molecules. OE is worth exploring further for its neuroprotectant properties in the prevention and treatment of PD.

Lindersin B from Lindernia crustacea induces neuritogenesis by activation of tyrosine kinase A/phosphatidylinositol 3 kinase/extracellular signal-regulated kinase signaling pathway

BACKGROUND

Neurotrophic factors such as nerve growth factor (NGF) play important roles in nervous system. NGF is a potential therapeutic drug for treatment of neurodegenerative diseases. However, because of physicochemical property, NGF cannot pass through the blood-brain barrier (BBB). Hence, small molecules which exhibit NGF-mimic activity and can pass through the BBB are considered to be promising drug candidates for treatment of such diseases.

PURPOSE

The present study was designed to isolate NGF-mimic substance from extract of natural products, determine their structures and investigate mechanism of action of the active substance.

METHODS

Extract of Lindernia crustacean was partitioned between water and ethyl acetate to obtain water layer and ethyl acetate layer samples, respectively, and then evaluated their neuritogenic activity in PC12 cells. The active sample was separated by open columns, followed by HPLC purification to obtain active compound. Then, specific inhibitors were used to investigate signaling pathway of neurite outgrowth induced by the active compound. Finally, western blot analysis was performed to confirm the pathway proposed by inhibitor experiments.

RESULTS

The ethyl acetate layer sample of extract of Lindernia crustacea exhibited significant neuritogenic activity. Two new compounds, named as linderside A and lindersin B, were isolated; their structures were elucidated by spectroscopic and chemical derivatization methods. Linderside A is a cucurbitane glycoside, whereas lindersin B is a cucurbitane triterpenoid. Each compound has an unusual isopentene unit, namely, a double bond bound to an unmodified isopropyl group at the end of cucurbitane triterpenoid side chain. Among them, lindersin B induced significant neurite outgrowth in PC12 cells, while linderside A was inactive against PC12 cells. Western blotting analysis results showed that lindersin B-induced neuritogenic activity depended on the activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK). Moreover, tyrosine kinase A (TrKA) and phosphatidylinositol 3 kinase (PI3K) were also involved in the signaling pathway.

CONCLUSIONS

Two new cucurbitane triterpenoids, linderside A and lindersin B, were isolated from Lindernia crustacean. Neurite outgrowth induced by lindersin B in PC12 cells depends on activation of TrkA/PI3K/ERK signaling pathway.

Confined Formation of Ultrathin ZnO Nanorods/Reduced Graphene Oxide Mesoporous Nanocomposites for High-Performance Room-Temperature NO2 Sensors

Here we demonstrate high-performance room-temperature NO₂ sensors based on ultrathin ZnO nanorods/reduced graphene oxide (rGO) mesoporous nanocomposites. Ultrathin ZnO nanorods were loaded on rGO nanosheets by a facile two-step additive-free solution synthesis involving anchored seeding followed by oriented growth. The ZnO nanorod diameters were simply controlled by the seed diameters associated with the spatial confinement effects of graphene oxide (GO) nanosheets. Compared to the solely ZnO nanorods and rGO-based sensors, the optimal sensor based on ultrathin ZnO nanorods/rGO nanocomposites exhibited higher sensitivity and quicker p-type response to parts per million level of NO₂ at room temperature, and the sensitivity to 1 ppm of NO₂ was 119% with the response and recovery time being 75 and 132 s. Moreover, the sensor exhibited full reversibility, excellent selectivity, and a low detection limit (50 ppb) to NO₂ at room temperature. In addition to the high transport capability of rGO as well as excellent NO₂ adsorption ability derived from ultrathin ZnO nanorods and mesoporous structures, the superior sensing performance of the nanocomposites was attributed to the synergetic effect of ZnO and rGO, which was realized by the electron transfer across the ZnO-rGO interfaces through band energy alignment.

Benzoate fraction from Gentiana rigescens Franch alleviates scopolamine-induced impaired memory in mice model in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

G. rigescens Franch (Long Dan Cao in Chinese) is a well-known TCM herb. It is clinically used with other drugs for the treatment of brain diseases such as epilepsy, postherpetic neuralgia in China.

AIM OF STUDY

In our previous study, the 11 dihydroxybenzoates compounds with NGF mimicking activity from G. rigescens Franch were found. In the present study, the neurogenesis and neuroprotection of a mixture of benzoates ( n-GS) were investigated in animal level.

MATERIALS AND METHODS

The NGF mimicking activity of n-GS from G. rigescens Franch was examined in PC12 cells. The neurogenesis effects of n-GS were investigated in ICR mice with 5-bromo-2-deoxyuridine (BrdU) and neuronal neclei (NeuN) double immunostaining. Furthermore, the neuroprotection effects of n-GS on the memory in a scopolamine (SCO)-induced mouse model were evaluated with animal behavior tests.

RESULTS

The NGF-mimicking function and neurogenesis of n-GS were observed in PC12 cells and in normal mice. Subsequently, we investigated the effects of n-GS on the memory in a SCO-induced mouse model. In Y-maze test, SCO significantly lowered the alternation. This finding was reversed by n-GS and donepezil (DONE). SCO significantly impaired the mice's performance in novel object recognition (NOR) and Morris water maze (MWM) tests. The time spent to explore the novel object was longer in the n-GS- and DONE-treated groups than in the SCO control group. In the MWM test, the escape latency of n-GS- and DONE-treated groups was shorter than that of the SCO control group. Mechanism study showed that SCO significantly reduced superoxide dismutase (SOD) but increased the activities of acetylcholinesterase (AChE) and the levels of malondialdehyde (MDA) in the hippocampus and cerebral cortex, which all can be improved by n-GS and DONE. Additionally, the phosphorylation of type 1 insulin-like growth factor (IGF-1) receptor, extracellular signal-regulated kinase (ERK), and cAMP responsive element-binding (CREB) protein in the hippocampus was significantly up-regulated in the treatment group compared with that in the SCO group.

CONCLUSIONS

n-GS could alleviate impaired memory of the SCO-induced mice model by inhibiting AChE activity and oxidative stress, and regulating the IGF-1R/ERK signaling pathway.

Synthesis and SAR Studies of Neuritogenic Gentiside Derivatives

Tetradecyl 2,3-dihydroxybenzoate (ABG-001) has been designed and synthesised as a lead compound to treat Alzheimer's disease, based on structure-activity relationships of gentisides. In this paper, the alkyl chain and ester linkage group of ABG-001 were modified. Consequently, several series of novel gentiside derivatives were designed and synthesised, and their neuritogenic activity was evaluated in PC12 cells. Among all the tested compounds, S-dodecyl 2,3-dihydroxybenzothioate (15d, named as ABG-199) was the most potent; the compound induced significant neurite outgrowth at 0.1 µM, which was comparable to that of nerve growth factor at the optimal concentration of 40 ng/mL and ABG-001 at 1 µM. A brief study on the mechanism of action of ABG-199 revealed that extracellular signal-regulated kinase phosphorylation was involved in ABG-199-induced neurite outgrowth in PC12 cells.