Gamma-Decanolactone Alters the Expression of GluN2B, A1 Receptors, and COX-2 and Reduces DNA Damage in the PTZ-Induced Seizure Model After Subchronic Treatment in Mice.

Gamma-decanolactone (GD) has been shown to reduce epileptic behavior in different models, inflammatory decreasing, oxidative stress, and genotoxic parameters. This study assessed the GD effect on the pentylenetetrazole (PTZ) model after acute and subchronic treatment. We evaluated the expression of the inflammatory marker cyclooxygenase-2 (COX-2), GluN2B, a subunit of the NMDA glutamate receptor, adenosine A1 receptor, and GD genotoxicity and mutagenicity. Male and female mice were treated with GD (300 mg/kg) for 12 days. On the tenth day, they were tested in the Hot Plate test. On the thirteenth day, all animals received PTZ (90 mg/kg), and epileptic behavior PTZ-induced was observed for 30 min. Pregabalin (PGB) (30 mg/kg) was used as a positive control. Samples of the hippocampus and blood were collected for Western Blotting analyses and Comet Assay and bone marrow to the Micronucleus test. Only the acute treatment of GD reduced the seizure occurrence and increased the latency to the first stage 3 seizures. Males treated with GD for 12 days demonstrated a significant increase in the expression of the GluN2B receptor and a decrease in the COX-2 expression. Acute and subchronic treatment with GD and PGB reduced the DNA damage produced by PTZ in males and females. There is no increase in the micronucleus frequency in bone marrow after subchronic treatment. This study suggests that GD, after 12 days, could not reduce PTZ-induced seizures, but it has been shown to protect against DNA damage, reduce COX-2 and increase GluN2B expression.

Trehalose-based neuroprotective autophagy inducers.

A small set of trehalose-centered putative autophagy inducers was rationally designed and synthesized, with the aim to identify more potent and bioavailable autophagy inducers than free trehalose, and to acquire information about their molecular mechanism of action. Several robust, high yield routes to key trehalose intermediates and small molecule prodrugs (2-5), putative probes (6-10) and inorganic nanovectors (12a - thiol-PEG-triazole-trehalose constructs 11) were successfully executed, and compounds were tested for their autophagy-inducing properties. While small molecules 2-11 showed no pro-autophagic behavior at sub-millimolar concentrations, trehalose-bearing PEG-AuNPs 12a caused measurable autophagy induction at an estimated 40 µM trehalose concentration without any significant toxicity at the same concentration.

Design, synthesis and biological evaluation of novel deoxyvasicinone-indole as multi-target agents for Alzheimer's disease.

In this study, a series of multifunctional hybrids (6a-6l) against Alzheimer's disease were designed and obtained by conjugating the pharmacophores of deoxyvasicinone and indole. These analogs of deoxyvasicinone-indole were evaluated as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), and as inhibitors of amyloid aggregation (Aß1-42) for treatment of Alzheimer's disease (AD). Subsequently, AChE induced Aß aggregation inhibition test was also performed for selected compounds. Biological activity results demonstrated that compound 6b was the most potent and balanced dual ChEs inhibitor with IC50 values 0.12 µM and 0.15 µM for eeAChE and eqBuChE, respectively. Kinetic analysis and docking study indicated that compound 6b was a mixed-type inhibitor for both AChE and BuChE. Compound 6b also found to be the best inhibitors of self-induced Aß1-42 aggregation with IC50 values of 1.21 µM. Compound 6b also afforded excellent inhibition of AChE-induced Aß1-42 aggregation by 81.1%. Overall, these results indicate that 6b may be considered as lead compound for the development of highly effective anti-AD drugs.

Safety Assessment of AAV2-hGDNF Administered Via Intracerebral Injection in Rats for Treatment of Parkinson's Disease.

Glial cell line-derived neurotrophic factor (GDNF) is a potent neuroprotective biologic in Parkinson's disease models. Adeno-associated viral vector serotype 2 (AAV2)-human GDNF safety was assessed in rats treated with a single intracerebral dose of vehicle, 6.8 × 108, 6.8 × 109, or 5.2 × 1010 vector genomes (vg)/dose followed by interim sacrifices on day 7, 31, 90, and 376. There were no treatment-related effects observed on food consumption, body weight, hematology, clinical chemistry, coagulation parameters, neurobehavioral parameters, organ weights, or serum GDNF and anti-GDNF antibody levels. Increased serum anti-AAV2 neutralizing antibody titers were observed in the 5.2 × 1010 vg/dose group. Histopathological lesions were observed at the injection site in the 6.8 × 109 vg/dose (day 7) and 5.2 × 1010 vg/dose groups (days 7 and 31) and consisted of gliosis, mononuclear perivascular cuffing, intranuclear inclusion bodies, and/or apoptosis on day 7 and mononuclear perivascular cuffing on day 31. GDNF immunostaining was observed in the injection site in all dose groups through day 376 indicating no detectable impacts of anti-AAV2 neutralizing antibody. There was no evidence of increased expression of calcitonin gene-related peptide or Swann cell hyperplasia in the cervical and lumbar spinal cord or medulla oblongata at the 5.2 × 1010 vg/dose level indicating lack of hyperplastic effects. In conclusion, no systemic toxicity was observed, and the local toxicity observed at the injection site appeared to be reversible demonstrating a promising safety profile of intracerebral AAV2-GDNF delivery. Furthermore, an intracerebral dose of 6.8 × 108 AAV2-GDNF vg/dose was considered to be a no observed adverse effect level in rats.

Synthesis and preliminary biological evaluation of naproxen-probenecid conjugate for central nervous system (CNS) delivery.

Naproxen, known as the most potent non-steroid anti-inflammatory drugs, is vitally crucial in the treatment of neurodegenerative diseases. However, due to the poor brain penetration ability, it causes serious adverse effects with the therapeutic doses. Predictably, these unfavorable factors have hindered its further application. In this study, a novel brain-targeting conjugate, Nap-Pro, was designed and synthesized. The chemical stability and metabolic stability of this conjugate were determined in phosphate buffer, blood serum and brain homogenate, respectively. The cytotoxicity of Nap-Pro was evaluated in b End. 3 cells. In addition, the brain targeting capacity of Nap-Pro was also investigated in vivo. Importantly, Nap-Pro showed excellent capacity to cross the brain-blood barrier (BBB), suggesting probenecid was a super carrier that enhanced the delivery of drugs into brain. Collectively, the probenecid modification was a promising strategy to develop the novel drug delivery systems for brain targeting.

TLR7 agonist modulation of postasphyxial neurophysiological and cardiovascular adaptations in preterm fetal sheep.

Activation of Toll-like receptors (TLRs) after hypoxic-ischemic brain injury can exacerbate injury but also alleviate cell loss, as recently demonstrated with the TLR7 agonist Gardiquimod (GDQ). However, TLR agonists also modulate vascular function and neuronal excitability. Thus, we examined the effects of TLR7 activation with GDQ on cardiovascular function and seizures after asphyxia in preterm fetal sheep at 0.7 gestation (104 days, term ∼147 days). Fetuses received sham asphyxia or asphyxia induced by umbilical cord occlusion for 25 min or asphyxia followed by a continuous intracerebroventricular infusion of 3.34 mg of GDQ from 1 to 4 h after asphyxia. Fetuses were monitored continuously for 72 h postasphyxia. GDQ treatment was associated with sustained, moderate hypertension for 72 h (P < 0.05), with a transient increase in heart rate. Electroencephalographic (EEG) power was suppressed for the entire postasphyxial period in both groups, whereas EEG spectral edge transiently increased during the GDQ infusion compared with asphyxia alone (P < 0.05), with higher ß- and lower δ-EEG frequencies (P < 0.05). This increase in EEG frequency was not related to epileptiform activity. After the GDQ infusion, there was earlier onset of high-amplitude stereotypic evolving seizures, with increased numbers of seizures and seizure burden (P < 0.05). Hemodynamic function and seizure activity are important indices of preterm wellbeing. These data highlight the importance of physiological monitoring during preclinical testing of potential neuroprotective strategies.

A review of pharmacological and pharmacokinetic properties of stachydrine.

Stachydrine is extracted from the leaves of Leonurus japonicus Houtt (or Motherwort, "Yi Mu Cao" in Traditional Chinese Medicine) and is the major bioactive ingredient. So far, stachydrine has demonstrated various bioactivities for the treatment of fibrosis, cardiovascular diseases, cancers, uterine diseases, brain injuries, and inflammation. The pharmacological and pharmacokinetic properties of stachydrine up to 2019 have been comprehensively searched and summarized. This review provides an updated summary of recent studies on the pharmacological activities of stachydrine. Many studies have demonstrated that stachydrine has strong anti-fibrotic properties (on various types of fibrosis) by inhibiting ECM deposition and decreasing inflammatory and oxidative stress through multiple molecular mechanisms (including TGF-ß, ERS-mediated apoptosis, MMPs/TIMPs, NF-κB, and JAK/STAT). The cardioprotective and vasoprotective activities of stachydrine are related to its inhibition of ß-MHC, excessive autophagy, SIRT1, eNOS uncoupling and TF, promotion of SERCA, and angiogenesis. In addition to its anticancer action, regulation of the uterus, neuroprotective effects, etc. the pharmacokinetic properties of stachydrine are also discussed.

Lupenone Protects Neuroblastoma SH-SY5y Cells Against Methamphetamine-Induced Apoptotic Cell Death via PI3K/Akt/mTOR Signaling Pathway.

Methamphetamine (METH) is an addictive psychostimulant showing neurotoxicity through neuronal apoptosis and the neuro-inflammatory pathway. Lupenone, a lupane triterpenoid, is an isolated compound exhibiting anti-oxidative, anti-inflammation, and anti-diabetic activities. However, whether lupenone plays a protective role against apoptosis induced by METH in SH-SY5y neuroblastoma cells remains unknown. In the present study, we elucidated that lupenone had no toxicity to SH-SY5y cells at different concentrations. On the other hand, we found that the treatment of SH-SY5y cells with an optimal concentration of lupenone could lead to protection against cell death induced by METH. AnnexinV/PI apoptosis analysis revealed a dramatically reduced level of the apoptotic cell population in lupenon and METH treated SH-SY5y cells. Moreover, diminished expression of anti-apoptotic proteins, including Bcl-2, Caspase3, Caspase7, and Caspase8 in METH-exposed SH-SY5y cells, was significantly recovered by treatment with lupenone. This protection in the expression of anti-apoptotic proteins was due to an increased phosphorylation level of PI3K/Akt in METH-treated SH-SY5y cells pre-incubated with lupenone. These findings suggest that lupenone can protect SH-SY5y cells against METH-induced neuronal apoptosis through the PI3K/Akt pathway.

Drug-induced Obstructive and Retrograde Nephropathy Associated with α2u-globulin in Male Rats.

The chemically induced accumulation of α2u-globulin protein in male rats causes specific renal lesions and subsequent nephropathy. Herein, we report additional parallel findings in the kidney of male rats consistent with obstructive and retrograde nephropathy. Kidney and urinary bladder samples were evaluated from Wistar rats treated with RG7129 for 2 week and 8 week and from an 8-week mechanistic study using females, intact and castrated males. Histopathological findings were present in intact males in all studies, including hyaline droplet accumulation and granular casts consistent with α2u-globulin nephropathy. In addition, tubular degeneration and regeneration, tubular changes extending from papilla to cortex, tubular dilation, and interstitial and luminal inflammation were observed consistent with retrograde and obstructive nephropathy. Renal and urinary lesions and their severity increased in a time- and dose-dependent manner. Urinalysis findings, including increases in leukocytes, protein, and in kidney biomarkers, kidney injury molecule 1 and clusterin, were present only in intact males. No treatment-related changes were observed in female rats or in castrated males. These results indicate that RG7129 induces α2u-globulin nephropathy, associated with retrograde and obstructive nephropathy secondary to precipitation in intact male rats only, constituting a species- and sex-specific syndrome that is not expected to occur in humans or other species.

Synthesis and biological evaluation of new N-benzylpyridinium-based benzoheterocycles as potential anti-Alzheimer's agents.

A novel series of benzylpyridinium-based benzoheterocycles (benzimidazole, benzoxazole or benzothiazole) were designed as potent acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors. The title compounds 4a-q were conveniently synthesized via condensation reaction of 1,2-phenylenediamine, 2-aminophenol or 2-aminothiophenol with pyridin-4-carbalehyde, followed by N-benzylation using various benzyl halides. The results of in vitro biological assays revealed that most of them, especially 4c and 4g, had potent anticholinesterase activity comparable or more potent than reference drug, donepezil. The kinetic study demonstrated that the representative compound 4c inhibits AChE in competitive manner. According to the ligand-enzyme docking simulation, compound 4c occupied the active site at the vicinity of catalytic triad. The compounds 4c and 4g were found to be inhibitors of Aß self-aggregation as well as AChE-induced Aß aggregation. Meanwhile, these compounds could significantly protect PC12 cells against H2O2-induced injury and showed no toxicity against HepG2 cells. As multi-targeted structures, compounds 4c and 4g could be considered as promising candidate for further lead developments to treat Alzheimer's disease.

Detrimental effects of 2-arachidonoylglycerol on whole blood platelet aggregation and on cerebral blood flow after a focal ischemic insult in rats.

2-Arachidonoylglycerol (2-AG) is a major modulator of blood flow and platelet aggregation and a potential neuroprotectant. The present study investigated, for the first time, the effects of 2-AG on cerebral blood flow (CBF) in the first critical hours during middle cerebral artery occlusion (MCAO) and on platelet aggregation in rats. Adult male Sprague-Dawley rats ( n = 30) underwent permanent MCAO under isoflurane anesthesia and were randomly assigned to receive either 2-AG (6 mg/kg iv), monoacylglycerol lipase inhibitor JZL-184 (10 mg/kg iv), or vehicle ( n = 6 rats/group) treatment. CBF and cardiovascular responses were measured, by a blinded investigator, for up to 4 h. In separate experiments, platelet aggregation by 2-AG (19-300 µM) was assessed by whole blood aggregometry ( n = 40). 2-AG and JZL-184 significantly increased the severity of the CBF deficit versus vehicle (20.2 ± 8.8% and 22.7 ± 6.4% vs. 56.4 ± 12.1% of pre-MCAO baseline, respectively, P < 0.05) but had no effect on blood pressure or heart rate. While JZL-184 significantly increased the number of thrombi after MCAO, this did not reach significance by 2-AG. 2-AG induced platelet aggregation in rat whole blood in a similar manner to arachidonic acid and was significantly reduced by the cyclooxygenase inhibitors indomethacin and flurbiprofen and the thromboxane receptor antagonist ICI 192,605 ( P < 0.05). This is the first study showing that 2-AG increases the severity of the CBF deficit during MCAO, and further interrogation confirmed 2-AG-induced platelet aggregation in rats. These findings are important because 2-AG had previously been shown to exert neuroprotective actions and therefore force us to reevaluate the circumstances under which 2-AG is beneficial. NEW & NOTEWORTHY 2-Arachidonoylglycerol (2-AG) has neuroprotective properties; however, the present study revealed that 2-AG increases the severity of the cerebral blood flow deficit during middle cerebral artery occlusion in rats. Further interrogation showed that 2-AG induces platelet aggregation in rats. These findings force us to reevaluate the circumstances under which 2-AG is beneficial.

Substituent effect of N-benzylated gramine derivatives that prevent the PP2A inhibition and dissipate the neuronal Ca2+ overload, as a multitarget strategy for the treatment of Alzheimer's disease.

Following the premises of the multitarget-directed ligands approach for the drug R&D against neurodegenerative diseases, where Alzheimer's disease (AD) outstands, we have synthesized and evaluated analogues of the gramine derivative ITH12657 (1-benzyl-5-methyl-3-(piperidin-1-ylmethyl-1H-indole, 2), which had shown important neuroprotective properties, such as blocking effect of voltage-gated Ca2+ channels (VGCC), and prevention of phosphoprotein phosphatase 2A (PP2A) inhibition. The new analogues present different substitutions at the pending phenyl ring, what slightly modified their pharmacological characteristics. The VGCC blockade was enhanced in derivatives possessing nitro groups, while the pro-PP2A feature was ameliorated by the presence of fluorine. Chlorine atoms supplied good activities over the two biological targets aimed; nevertheless that substitution provoked loss of viability at 100-fold higher concentrations (10 µM), what discards them for a deeper pharmacological study. Overall, the para-fluorine derivative of ITH12657 was the most promising candidate for further preclinical assays.

Dihydroactinidiolide, a natural product against Aß25-35 induced toxicity in Neuro2a cells: Synthesis, in silico and in vitro studies.

Synthesis of natural products has speeded up drug discovery process by minimizing the time for their purification from natural source. Several diseases like Alzheimer's disease (AD) demand exploring multi targeted drug candidates, and for the first time we report the multi AD target inhibitory potential of synthesized dihydroactinidiolide (DA). Though the activity of DA in several solvent extracts have been proved to possess free radical scavenging, anti bacterial and anti cancer activities, its neuroprotective efficacy has not been evidenced yet. Hence DA was successfully synthesized from ß-ionone using facile two-step oxidation method. It showed potent acetylcholinesterase (AChE) inhibition with half maximal inhibitory concentration (IC50) 34.03 nM, which was further supported by molecular docking results showing strong H bonding with some of the active site residues such as GLY117, GLY119 and SER200 of AChE. Further it displayed DPPH and (.NO) scavenging activity with IC50 value 50 nM and metal chelating activity with IC50 >270 nM. Besides, it significantly prevented amyloid ß25-35 self-aggregation and promoted its disaggregation at 270 nM. It did not show cytotoxic effect towards Neuro2a (N2a) cells up to 24 h at 50 and 270 nM while it significantly increased viability of amyloid ß25-35 treated N2a cells through ROS generation at both the concentrations. Cytotoxicity profile of DA against human PBMC was quite impressive. Hemolysis studies also revealed very low hemolysis i.e. minimum 2.35 to maximum 5.61%. It also had suitable ADME properties which proved its druglikeness. The current findings demand for further in vitro and in vivo studies to develop DA as a multi target lead against AD.

Intermittent convection-enhanced delivery of GDNF into rhesus monkey putamen: absence of local or cerebellar toxicity.

Glial cell line-derived neurotrophic factor (GDNF) has demonstrated neurorestorative and neuroprotective effects in rodent and nonhuman primate models of Parkinson's disease. However, continuous intraputamenal infusion of GDNF (100 µg/day) resulted in multifocal cerebellar Purkinje cell loss in a 6-month toxicity study in rhesus monkeys. It was hypothesized that continuous leakage of GDNF into the cerebrospinal fluid compartment during the infusions led to down-regulation of GDNF receptors on Purkinje cells, and that subsequent acute withdrawal of GDNF then mediated the observed cerebellar lesions. Here we present the results of a 9-month toxicity study in which rhesus monkeys received intermittent intraputamenal infusions via convection-enhanced delivery. Animals were treated with GDNF (87.1 µg; N = 14) or vehicle (N = 6) once every 4 weeks for a total of 40 weeks (11 treatments). Four of the GDNF-treated animals were utilized in a satellite study assessing the impact of concomitant catheter repositioning prior to treatment. In the main study, eight animals (5 GDNF, 3 control) were euthanized at the end of the treatment period, along with the four satellite study animals, while the remaining eight animals (5 GDNF, 3 control) were euthanized at the end of a 12-week recovery period. There were no GDNF-related adverse effects and in particular, no GDNF-related microscopic findings in the brain, spinal cord, dorsal root ganglia, or trigeminal ganglia. Therefore, 87.1 µg/4 weeks is considered the no observed adverse effect level for GDNF in rhesus monkeys receiving intermittent, convection-enhanced delivery of GDNF for 9 months.

Dexmedetomidine Combined with Therapeutic Hypothermia Is Associated with Cardiovascular Instability and Neurotoxicity in a Piglet Model of Perinatal Asphyxia.

The selective α2-adrenoreceptor agonist dexmedetomidine has shown neuroprotective, analgesic, anti-inflammatory, and sympatholytic properties that may be beneficial in neonatal encephalopathy (NE). As therapeutic hypothermia is only partially effective, adjunct therapies are needed to optimize outcomes. The aim was to assess whether hypothermia + dexmedetomidine treatment augments neuroprotection compared to routine treatment (hypothermia + fentanyl sedation) in a piglet model of NE using magnetic resonance spectroscopy (MRS) biomarkers, which predict outcomes in babies with NE, and immunohistochemistry. After hypoxia-ischaemia (HI), 20 large White male piglets were randomized to: (i) hypothermia + fentanyl with cooling to 33.5°C from 2 to 26 h, or (ii) hypothermia + dexmedetomidine (a loading dose of 2 µg/kg at 10 min followed by 0.028 µg/kg/h for 48 h). Whole-brain phosphorus-31 and regional proton MRS biomarkers were assessed at baseline, 24, and 48 h after HI. At 48 h, cell death was evaluated over 7 brain regions by means of transferase-mediated d-UTP nick end labeling (TUNEL). Dexmedetomidine plasma levels were mainly within the target sedative range of 1 µg/L. In the hypothermia + dexmedetomidine group, there were 6 cardiac arrests (3 fatal) versus 2 (non-fatal) in the hypothermia + fentanyl group. The hypothermia + dexmedetomidine group required more saline (p = 0.005) to maintain blood pressure. Thalamic and white-matter lactate/N-acetylaspartate did not differ between groups (p = 0.66 and p = 0.21, respectively); the whole-brain nucleotide triphosphate/exchangeable phosphate pool was similar (p = 0.73) over 48 h. Cell death (TUNEL-positive cells/mm2) was higher in the hypothermia + dexmedetomidine group than in the hypothermia + fentanyl group (mean 5.1 vs. 2.3, difference 2.8 [95% CI 0.6-4.9], p = 0.036). Hypothermia + dexmedetomidine treatment was associated with adverse cardiovascular events, even within the recommended clinical sedative plasma level; these may have been exacerbated by an interaction with either isoflurane or low body temperature. Hypothermia + dexmedetomidine treatment was neurotoxic following HI in our piglet NE model, suggesting that caution is vital if dexmedetomidine is combined with cooling following NE.

Phenytoin: neuroprotection or neurotoxicity?

Phenytoin is an 80-year young molecule and new indications are still emerging. The neuroprotective potential of phenytoin has been evaluated for decades. Recently, a positive phase II trial supported its further development in the treatment of optic neuritis in multiple sclerosis. In 1942, however, peripheral neuritis was first reported to be an adverse event of phenytoin, and since then a small but steady stream of publications discussed peripheral polyneuropathy as being a possible adverse event of phenytoin. We have reviewed the literature and concluded there is some supportive evidence for a reversible polyneuropathy after the oral use of phenytoin, though with no evidence for clear neurotoxicity on the level of peripheral nerves. This is probably due to the fact that the pharmacological effects of phenytoin, based on the stabilizing effect of the voltage-gated sodium channels, make impairment of nerve conduction in asymptomatic and symptomatic reversible polyneuropathies plausible. Clear toxically-induced phenytoin-related polyneuropathies, however, are extremely rare and are always related to high dose or high plasma levels of phenytoin, mostly developing during many years of therapy. We could only find one case of a probable reversible chronic phenytoin intoxication resulting in a biopsy proven axonal atrophy with secondary demyelination and signs of remyelination. All case series and case reports published are insufficient in detail to prove a clear causal relation between phenytoin intake and the induction of a peripheral polyneuropathy. Phenytoin does not lead to irreversible toxicity of the peripheral nerves and might, on the other hand, have neuroprotective properties.

Gelidiella acerosa protects against Aß 25-35-induced toxicity and memory impairment in Swiss Albino mice: an in vivo report.

CONTEXT: Alzheimer's disease (AD) is believed to develop due to deposition of ß-amyloid (Aß) peptide. Hence, efforts are being made to develop potent drug that target amyloid hypothesis. OBJECTIVE: The present study explores the effect of the seaweed Gelidiella acerosa (Forsskål) Feldmann & Hamel (Gelidiellaceae) against Aß 25-35 peptide in Swiss albino mice. MATERIALS AND METHODS: The animals were administered through intracerebroventricular (ICV) injection with the Aß 25-35 peptide (10 µg/10 µL/ICV site) on 21st day of the pretreatment of G. acerosa (whole plant) benzene extract (200 and 400 mg/kg bw). On day 30, animals were sacrificed and brain tissue homogenate was prepared. The activities of AChE, BuChE, b-secretase, MAO-B, and caspase-3 were determined, and Bax expression was assessed by Western blotting. RESULTS: Gelidiella acerosa benzene extract restored the level of antioxidant enzymes and prevented lipid and protein oxidation significantly (p < 0.05). The extract protected the mice from cholinergic deficit significantly (p < 0.05) by inhibiting the activities of AChE and BuChE, which was about 0.116 ± 0.0088 U/mg of protein and 0.011 ± 0.0014 U/mg of protein respectively, which was otherwise increased in peptide-treated group (0.155 ± 0.007 U/mg of protein and 0.015 ± 0.0012 U/mg of protein respectively). Interestingly, G. acerosa benzene extract inhibited ß-secretase and MAO-B activity. Reduction (p < 0.05) in level of caspase-3 activity and Bax expression suggests that G. acerosa protects the cells from apoptosis. DISCUSSION AND CONCLUSION: The results suggest that G. acerosa possesses excellent neuroprotective potential against peptide mediated toxicity under in vivo conditions.

Slow-binding inhibition of cholinesterases, pharmacological and toxicological relevance.

Slow-binding inhibition (SBI) of enzymes is characterized by slow establishment of enzyme-inhibitor equilibrium. Cholinesterases (ChEs) display slow onset of inhibition with certain inhibitors. After a survey of SBI mechanisms, SBI of ChEs is examined. SBI results either from simple slow interaction, induced-fit, or slow conformational selection. In some cases, the slow equilibrium is followed by an irreversible chemical step. This later was observed for the interaction of ChEs with certain irreversible inhibitors. Because slow-binding inhibitors present pharmacological advantages over classical reversible inhibitors (e.g. long target-residence times, resulting in prolonged efficacy with minimal unwanted side effects), slow-binding inhibitors of ChEs are promising new drugs for treatment of Alzheimer disease, myasthenia, and neuroprotection. SBI is also of toxicological importance; it may play a role in mechanisms of resistance and protection against poisoning by irreversible agents.

Embryo-fetal development toxicity of honokiol microemulsion intravenously administered to pregnant rats.

The aim of this study was to evaluate the embryo-fetal development toxicity of honokiol microemulsion. The drug was intravenously injected to pregnant SD rats at dose levels of 0, 200, 600 and 2000 µg/kg/day from day 6-15 of gestation. All the pregnant animals were observed for body weights and any abnormal changes and subjected to caesarean-section on gestation day (GD) 20; all fetuses obtained from caesarean-section were assessed by external inspection, visceral and skeletal examinations. No treatment-related external alterations as well as visceral and skeletal malformations were observed in honokiol microemulsion groups. There was no significant difference in the body weight gain of the pregnant rats, average number of corpora lutea, and the gravid uterus weight in the honokiol microemulsion groups compared with the vehicle control group. However, at a dose level of 2000 µg/kg/day, there was embryo-fetal developmental toxicity observed, including a decrease in the body length and tail length of fetuses. In conclusion, the no-observed-adverse-effect level (NOAEL) of honokiol microemulsion is 600 µg/kg/day, 75 times above the therapeutic dosage and it has embryo-fetal toxicity at a dose level of 2000 µg/kg/day, which is approximately 250 times above the therapeutic dosage.

Genoprotective and neuroprotective effects of Daphne gnidium leaf methanol extract, tested on male mice.

Methanol extract of Daphne gnidium leaves was assessed for its antigenotoxic and neuroprotective effects through antioxidant and antibutyrylcholinesterase activities. Antigenotoxic activity was evaluated against methyl methanesulfonate injected intraperitoneally to mice, using the comet assay. The protective effect of D. gnidium reached 99.12%, at the lowest tested dose (44 mg/kg b.w.) in kidney cells, and 92.16% at the dose of 88 mg/kg b.w. in blood cells. The extract was dissolved in water and administrated to mice by intraperitoneal injection. Antioxidant activity was tested against DPPH radicals. It reached a maximum of 74.52% with an IC50 value of 45 µg/ml. Anticholinesterase activity was determined against butyrylcholinesterase, an enzyme linked to Alzheimer disease. The extract exhibited antibutyrylcholinestrase effect with an inhibition percentage of 35.82% at the lowest tested dose (44 mg/kg b.w.).