Adenosine A2A Receptor Blockade Provides More Effective Benefits at the Onset Rather than after Overt Neurodegeneration in a Rat Model of Parkinson's Disease.

Adenosine A2A receptor (A2AR) antagonists are the leading nondopaminergic therapy to manage Parkinson's disease (PD) since they afford both motor benefits and neuroprotection. PD begins with a synaptic dysfunction and damage in the striatum evolving to an overt neuronal damage of dopaminergic neurons in the substantia nigra. We tested if A2AR antagonists are equally effective in controlling these two degenerative processes. We used a slow intracerebroventricular infusion of the toxin MPP+ in male rats for 15 days, which caused an initial loss of synaptic markers in the striatum within 10 days, followed by a neuronal loss in the substantia nigra within 30 days. Interestingly, the initial loss of striatal nerve terminals involved a loss of both dopaminergic and glutamatergic synaptic markers, while GABAergic markers were preserved. The daily administration of the A2AR antagonist SCH58261 (0.1 mg/kg, i.p.) in the first 10 days after MPP+ infusion markedly attenuated both the initial loss of striatal synaptic markers and the subsequent loss of nigra dopaminergic neurons. Strikingly, the administration of SCH58261 (0.1 mg/kg, i.p. for 10 days) starting 20 days after MPP+ infusion was less efficacious to attenuate the loss of nigra dopaminergic neurons. This prominent A2AR-mediated control of synaptotoxicity was directly confirmed by showing that the MPTP-induced dysfunction (MTT assay) and damage (lactate dehydrogenase release assay) of striatal synaptosomes were prevented by 50 nM SCH58261. This suggests that A2AR antagonists may be more effective to counteract the onset rather than the evolution of PD pathology.

Hirsutinolide- and Cadinanolide-type Sesquiterpene Lactones from Lessingianthus rubricaulis (Vernonieae, Asteraceae).

Sesquiterpene lactones are an important class of secondary metabolites frequently isolated from Lessingianthus genus that present a variety of biological properties, such as antimalarial, anti-inflammatory, antileishmanial, antitrypanosomal and anticancer. The limited phytochemical studies and the importance of this class of compounds isolated from Lessingianthus led us to study this genus. In this work, we focused on the phytochemical investigation and dereplication based on UHPLC-HRMS/MS and molecular networking of L. rubricaulis. Chemical investigation resulted in the isolation of several hirsutinolide-type sesquiterpene lactones including a new hirsutinolide derivative, 8,10α-hydroxy-1,13-bis-O-methylhirsutinolide, besides a cadinanolide and flavonoids. The dereplication study resulted in the identification of three known flavonoids, six known hirsutinolides and two known cadinanolides. Moreover, a fragmentation pathway for cadinanolide-type sesquiterpene lactones was proposed. These results contribute to chemotaxonomic studies and demonstrates the potential of Lessingianthus genus.

Mass spectrometry as a tool for the dereplication of specialised metabolites from Pterocaulon angustifolium DC.

Pterocaulon genus comprises 26 species, half of them have been phytochemical investigations regarding the chemical composition, and coumarins have been considered the chemotaxonomic markers in the genus. Herein Pterocaulon angustifolium DC (Asteraceae), a native plant from Brazil, is investigated for the first time. Twenty-six compounds were isolated from aerial parts of P. angustifolium DC., being 5 triterpenes, 4 phytosterols, 9 flavonoids, 3 phenolic acids, and 5 coumarins. Moreover, a total of 177 compounds were putatively identified using the dereplication technique by UHPLC-HRMS/MS, more than 50% correspond to flavonoids and coumarins. Although 41 different coumarins have already been reported in Pterocaulon genus, 16 were identified for the first time in this study. Crude ethanolic extract and fractions of P. angustifolium were also biologically investigates, and dichloromethane fraction was the most active fraction in the evaluation of antiproliferative, antioxidant, antimicrobial and cholinesterase inhibitory activities.

The chemistry of Vernonanthura nudiflora (Less.) H. Rob. flowers and its antimicrobial activities.

Twenty-one known specialised metabolites were isolated from the flowers of Vernonanthura nudiflora (Less.) H. Rob., the structures of the compounds were established based on 1 D and 2 D NMR spectroscopic experiments. Others 28 compounds were putatively identified using the dereplication technique by UHPLC-HRMS/MS. Twenty-three of the compounds are being reported for the first time in this species. The mixture of sesquiterpene lactones piptocarphins A and B (17 + 18), and the flavone velutin (14) were tested against several microorganisms and showed promising activity against Mycobacterium tuberculosis with MIC of 15.6 µg/mL and 31.2 µg/mL, respectively. Furthermore, 17 + 18 showed greater cytotoxicity against VERO cells (IC50 = 7.0 ± 1.73) compared to compound 14 (IC50 85.0 ± 10.6 µg/mL). These findings reveal the feasibility of using the UHPLC-ESI-HRMS/MS-based dereplication strategy in complex fractions to identify specialised metabolites, moreover to V. nudiflora flowers being a source of compounds with antimycobacterial potential.

Chemical constituents and dereplication study of Lessingianthus brevifolius (Less.) H.Rob. (Asteraceae) by UHPLC-HRMS and molecular networking.

Chemical investigation of Lessingianthus brevifolius (Less.) H.Rob. aerial parts resulted in the isolation of the hirsutinolide-type sesquiterpene lactones piptocarphol, spicatolide D, piptocarphin D and 8α-acetoxy-10α-hydroxy-13-O-methylhirsutinolide, and also of a cadinanolide identified as 13-O-methylvernojalcanolide 8-O-acetate. Flavonoids, triterpenes and chlorogenic acids were also isolated. In addition, a dereplication study was carried out using UHPLC-HRMS and molecular networking, resulting in the identification of fifteen known compounds, being two sesquiterpene lactones and thirteen flavonoids. Some of the compounds are being described for the first time in L. brevifolius, and also in the Lessingianthus genus.

TOCSY, hydrogen decoupling and computational calculations to an unequivocal structural elucidation of a new sesquiterpene derivative and identification of other constituents from Praxelis sanctopaulensis.

INTRODUCTION: Praxelis genus comprises 24 species, however, only two species of this genus have been chemically investigated. Here we investigated Praxelis sanctopaulensis, a native plant from Brazil, that occurs mainly in Cerrado regions. OBJECTIVE: The goal was to identify the specialised metabolites from P. sanctopaulensis, and compare with those described from Praxelis and Chromolaena species. METHODS: The phytochemical study of P. sanctopaulensis was performed through different chromatography techniques, including high-performance liquid chromatography (HPLC), gas chromatography flame ionisation detector (GC-FID), and ultra-high-performance liquid chromatography high-resolution tandem mass spectrometry (UHPLC-HRMS/MS). The structures of the compounds were established based on spectroscopic analysis, total correlated spectroscopy (TOCSY), hydrogen decoupling and computational calculations was used to an unequivocal structural elucidation of a new sesquiterpene. The antioxidant activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP), and antimicrobial assay was performed by the microdilution method. Comparison of the flavonoids described P. sanctopaulensis was carried out using principal component analysis. RESULTS: The phytochemical investigation of P. sanctopaulensis led to the isolation of a pair of diastereomers, praxilone A and praxilone B. Seven known compounds were isolated from this species, another 14 fatty acids were detected in hexane fraction, and 26 compounds were identified from ethyl acetate fraction. All these compounds are being described for the first time in this species, with the exception of viridifloric acid. The ethyl acetate fraction showed potent antioxidant activity. CONCLUSIONS: Forty-seven compounds are described from P. sanctopaulensis. The combination of different techniques of nuclear magnetic resonance (NMR) spectroscopy and computational calculations allowed the unequivocal structure elucidation of a new cadinene. The clustering analysis showed similarities between the flavonoids identified in P. sanctopaulensis and in Chromolaena species.

Phytoprostane and phenolic compounds from Chromolaena palmaris.

The chemical investigation of Chromolaena palmaris (Sch.Bip. ex Baker) R.M. King & H. Rob. expands the phytochemical composition knowledge of Chromolaena genus, since this is the first chemical investigation of this species. Twenty-five compounds were identified, including a phytoprostane, 17 flavonoids, 6 phenolic acids, and a caffeoyl-glucoside derivative obtained by classical chromatography and UHPLC-HRMS/MS analysis. Moreover, anti-Mycobacterium tuberculosis and antiproliferative activities of C. palmaris were evaluated. Dichloromethane fraction showed cytotoxicity towards human cancer cell lines, presenting TGI values on glioma (U251) of 27.8 µg mL-1. Furthermore, compounds 1 and 2 exhibited antimicrobial activity against Mycobacterium tuberculosis with MIC of 62.5 and 15.6 µg mL-1, respectively.

Molecular diversity of rhizobia-nodulating native Mimosa of Brazilian protected areas.

Symbiotic Paraburkholderia have been increasingly studied in the past 20 years, especially when associated with Mimosa; however, studies with native/endemic species are still scarce. In this study, thirty strains were isolated from root nodules of native Mimosa paranapiacabae and M. micropteris in two locations of the Campos Gerais. The BOX-PCR fingerprinting revealed high genomic diversity, and the 16S rRNA phylogeny clustered the strains in three distinct groups (GI, GII, GIII), with one strain occupying an isolated position. Phylogenetic analysis with four concatenated housekeeping genes (atpD + gltB + gyrB + recA) confirmed the same clusters of 16S rRNA, and the closest species were P. nodosa BR 3437T and P. guartelaensis CNPSo 3008T; this last one isolated from another Mimosa species of the Campos Gerais. The phylogenies of the symbiotic genes nodAC and nifH placed all strains in a well-supported branch with the other species of the symbiovar mimosae. The phylogenetic analyses indicated that the strains represent novel lineages of sv. mimosae and that endemic Mimosa coevolved with indigenous Paraburkholderia in their natural environments.

Chromolaena laevigata (Asteraceae) as a source of endophytic non-aflatoxigenic Aspergillus flavus: chemical profile in different culture conditions and biological applications.

Endophytes are microorganisms that form symbiotic relationships with their host. These microorganisms can produce a variety of secondary metabolites, some of which have inhibitory effects on pests and pathogens or even act to promote plant growth. Due to these characteristics, these microorganisms are used as sources of biologically active substances for a wide range of biotechnological applications. Based on that, the aim of this study was to evaluate the production of metabolites of the endophytic Aspergillus flavus CL7 isolated from Chromolaena laevigata, in four different cultivation conditions, and to determine the antimicrobial, cytotoxic, antiviral, and antioxidant potential of these extracts. The multiphasic approach used to identify this strain was based on morphology and ITS gene sequence analysis. The chemical investigation of A. flavus using potato dextrose and minimal medium, using both stationary and agitated methods, resulted in the isolation of kojic acid, α-cyclopiazonic acid, and 20,25-dihydroxyaflavinine. Another 18 compounds in these extracts were identified by UHPLC-HRMS/MS, of which dideacetyl parasiticolide A has been described for the first time from A. flavus. Aflatoxins, important chemomarkers of A. flavus, were not detected in any of the extracts, thus indicating that the CL7 strain is non-aflatoxigenic. The biological potential of all extracts was evaluated, and the best results were observed for the extract obtained using minimal medium against Trichophyton rubrum and Mycobacterium tuberculosis.

New cadinene-sesquiterpene from Chromolaena laevigata (lam.) R. M. King & H. Rob (Asteraceae) aerial parts and biological activities.

Phytochemical investigation of Chromolaena laevigata led to the isolation of a new cadinene-sesquiterpene, chromolaevigone glucoside (1), along with nine known compounds: daucosterol (2), stigmasterol glycoside (3), stigmasterol (4), ß-sitosterol (5), pilloin (6), gonzalitosin I (7), quercetin-3-O-α-rhamnopyranoside (8), 7,7-dihydroxy-calamen-12-oic acid lactone (9) and trachelanthic acid (10). Others 11 known compounds were identified by UHPLC-HRMS/MS. These compounds are being described for the first time in this species, with the exception of cadinene 9. Furthermore, due to the limitation of pharmacological studies, antiproliferative, antiviral, and antimicrobial activities of C. laevigata were evaluated. The best results in the cytotoxicity, antimicrobial and antiproliferative tests, presenting GI50 values on ovarian tumour cells (OVCAR-03) of 1.9 µg mL-1 and kidney (786-0) of 2.5 µg mL-1 were observed for the hexanic fraction.[Figure: see text].

Cytotoxic sesquiterpene lactones from Campuloclinium macrocephalum (=Eupatorium macrocephalum).

Three undescribed germacranolide sesquiterpene lactones, named macrocephalides A-C, along with known steroids, triterpenes and flavonoids were isolated from the aerial parts of Campuloclinium macrocephalum. The structures of the undescribed compounds were elucidated with basis on their 1D and 2D-NMR, and HR-ESI-MS data. Their absolute configurations were assigned by comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Additionally, macrocephalides A-C were evaluated for their in vitro cytotoxic activities against nine human cancer cell lines. Macrocephalides A and B exhibited moderate to potent cytotoxic activity, inhibiting 50% of cell growth (GI50) at concentrations ranging from 0.576 to 6.37 µM.

Enhanced ATP release and CD73-mediated adenosine formation sustain adenosine A2A receptor over-activation in a rat model of Parkinson's disease.

BACKGROUND AND PURPOSE: Parkinson's disease (PD) involves an initial loss of striatal dopamine terminals evolving into degeneration of dopamine neurons in substantia nigra (SN), which can be modelled by 6-hydroxydopamine (6-OHDA) administration. Adenosine A2A receptor blockade attenuates PD features in animal models, but the source of the adenosine causing A2A receptor over-activation is unknown. As ATP is a stress signal, we have tested if extracellular catabolism of adenine nucleotides into adenosine (through ecto-5'-nucleotidase or CD73) leads to A2A receptor over-activation in PD. EXPERIMENTAL APPROACH: Effects of blocking CD73 with α,ß-methylene ADP (AOPCP) were assayed in 6-OHDA-treated rats and dopamine-differentiated neuroblastoma SH-SY5Y cells. KEY RESULTS: 6-OHDA increased ATP release and extracellular conversion into adenosine through CD73 up-regulation in SH-SY5Y cells. Removing extracellular adenosine with adenosine deaminase, blocking CD73 with AOPCP, or blocking A2A receptors with SCH58261 were equi-effective in preventing 6-OHDA-induced damage in SH-SY5Y cells. In vivo striatal exposure to 6-OHDA increased ATP release and extracellular formation of adenosine from adenosine nucleotides and up-regulated CD73 and A2A receptors in striatal synaptosomes. Intracerebroventricular administration of AOPCP phenocopied effects of SCH58261, attenuating 6-OHDA-induced (a) increase of contralateral rotations after apomorphine, (b) reduction of dopamine content in striatum and SN, (c) loss of TH staining in striatum and SN, (d) motor dysfunction in the cylinder test, and (e) short-term memory impairment in the object recognition test. CONCLUSION AND IMPLICATIONS: Our data indicate that increased ATP-derived adenosine formation is responsible for A2A receptor over-activation in PD, suggesting CD73 as a new target to manage PD.

Structural Characterization and Biological Evaluation of 18-Nor-ent-labdane Diterpenoids from Grazielia gaudichaudeana.

The phytochemical investigation of Grazielia gaudichaudeana aerial parts yielded 15 compounds, including diterpenes, triterpenes, sterols and flavonoids. With exception to ent-kaurenoic acid diterpenes, the compounds isolated are being described for the first time in this species. Some unusual 1 H-NMR chemical shifts of 18-nor-ent-labdane (7-9) led us carry out a conformational analysis by theoretical calculations in order to support the experimental data. Moreover, due to the limitation of studies focused on pharmacological potential of Grazielia gaudichaudeana, the present study was carried out to investigate the antioxidant, antiproliferative, antiviral, antileishmanial and antimicrobial activities from the extract, fractions and isolated compounds obtained from this species. Ethyl acetate fraction showed significant activity in the antiproliferative assay, with GI50 range of 3.9 to 27.2 µg mL-1 . Dichloromethane fraction, rich in diterpenoids, inhibited all human tumor cell lines tested, and the nor-labdane 7 showed potent cytotoxic activity against glioma and ovary cancer cell lines.

(-)-α-bisabolol prevents neuronal damage and memory deficits through reduction of proinflammatory markers induced by permanent focal cerebral ischemia in mice.

The pathophysiology of ischemic stroke involves multiple events such as inflammation and oxidative stress which will lead to neuronal death and cognitive deficits. The (-)-α-bisabolol is a monocyclic sesquiterpene alcohol found in various plants and mainly in Matricaria chamomilla, which exerts antioxidant, anti-inflammatory, and anti-apoptotic activities. The aim of this work was to investigate the neuroprotective effects of (-)-α-bisabolol in mice underwent permanent occlusion of the middle cerebral artery (pMCAO). Animals were treated with (-)-α-bisabolol (50, 100 and 200 mg/kg/day, orally) or vehicle (3% tween 80) one day before and 1 h after pMCAO and the treatment continued once daily for the following five days. The treatment with (-)-α-bisabolol (100 and 200 mg/kg) significantly reduced the infarcted area and neurological deficits caused by pMCAO. (-)-α-bisabolol at the 200 mg/kg dose increased cell viability and decreased neuronal degeneration, as evaluated by cresyl violet and Fluoro-Jade C stainings, respectively. (-)-α-bisabolol also increased the locomotor activity which was reduced by cerebral ischemia and improved pMCAO-induced working, spatial, object recognition, and aversive memories deficits. (-)-α-bisabolol (200 mg/kg) significantly prevented the increase of myeloperoxidase (MPO) activity, TNF-α immunoreactivity in the temporal cortex, and the increase of iNOS both in the temporal cortex and in the striatum. (-)-α-bisabolol treatment also prevented astrogliosis in these areas. These data showed that (-)-α-bisabolol provides neuroprotective action probably due to its anti-inflammatory activity, although other mechanisms cannot be discarded.

Phylogenetic diversity of rhizobia nodulating native Mimosa gymnas grown in a South Brazilian ecotone.

Floristic surveys performed in "Campos Gerais" (Paraná, Brazil), an ecotone of Mata Atlântica and Cerrado biomes, highlights the richness and relative abundance of the family Fabaceae and point out the diversity and endemism of Mimosa spp. Our study reports the genetic diversity of rhizobia isolated from root nodules of native/endemic Mimosa gymnas Barneby in three areas of Guartelá State Park, an important conservation unit of "Campos Gerais". Soils of the sample areas were characterized as sandy, acid, poor in nutrients and organic matter. The genetic variability among the isolates was revealed by BOX-PCR genomic fingerprinting. Phylogeny based on 16S rRNA gene grouped the strains in a large cluster including Paraburkholderia nodosa and P. bannensis, while recA-gyrB phylogeny separated the strains in two groups: one including P. nodosa and the other without any described Paraburkholderia species. MLSA confirmed the separate position of this second group of strains within the genus Paraburkholderia and the nucleotide identity of the five concatened housekeeping genes was 95.9% in relation to P. nodosa BR 3437T. Phylogram based on symbiosis-essential nodC gene was in agreement with 16S rRNA analysis. Our molecular phylogenetic analysis support that Paraburkholderia are the main symbionts of native Mimosa in specific edaphic conditions found in South America and reveal the importance of endemic/native leguminous plants as reservoirs of novel rhizobial species.

Neuroprotective Activities of Spirulina platensis in the 6-OHDA Model of Parkinson's Disease Are Related to Its Anti-Inflammatory Effects.

Spirulina platensis (SPI) is a cyanobacterium, presenting anti-inflammatory and antioxidant actions. Considering the importance of inflammation and oxidative stress in Parkinson's disease (PD), SPI neuroprotective effects were evaluated in a model of PD. Male Wistar rats were divided into: sham-operated (SO), untreated 6-OHDA and 6-OHDA treated with SPI (25 and 50 mg/kg, p.o.). The 6-OHDA was injected into the right striata and SPI treatments started 24 h later for 2 weeks. The SO and untreated 6-OHDA-lesioned groups were administered with distilled water, for the same period. Afterwards, the animals were subjected to the apomorphine-induced rotational test and euthanized for striatal measurements of DA and DOPAC, nitrite and TBARS and immunohistochemistry assays for TH, DAT, iNOS and COX-2. SPI reduced the apomorphine-induced rotational behavior, DA and DOPAC depletions and nitrite and TBARS increases, at its high dose. Furthermore, TH and DAT immunoreactivities in the lesioned striatum of the untreated 6-OHDA-lesioned group were attenuated by SPI. Similarly, immunoreactivities for iNOS and COX-2 were also decreased after SPI treatments. In conclusion, we showed that behavioral and neurochemical alterations in hemiparkinsonian rats were partly reversed by SPI, characterizing the neuroprotective potential of Spirulina and stimulating translational studies focusing on its use as an alternative treatment for PD.

Neuroinflammatory response to experimental stroke is inhibited by boldine.

Inflammation plays a pivotal role in the development of ischemic brain damage. Astrocyte activation promotes the production of several proinflammatory mediators, such as TNF-α and iNOS. Eventually, neuronal death occurs, leading to the development of motor and memory deficits in patients. Boldine is the main alkaloid in the leaves and bark of the Peumus boldus Molina, and has anti-inflammatory and antioxidant properties. The aim of this work was to investigate the neuroprotective effect of boldine on neuroinflammation and memory deficits induced by permanent middle cerebral artery occlusion (pMCAO) in mice. Thirty minutes before pMCAO and during the next 5 days, animals received vehicle (0.025 µmol/l HCl) or boldine (8, 16 and 25 mg/kg, intraperitoneally). The extension of the infarct area, neurological scores, and myeloperoxidase activity were evaluated 24 h after pMCAO. Locomotor activity, working, and aversive memory were evaluated 72 h after pMCAO, object recognition memory was tested 96 h after pMCAO, and spatial memory was tested 120 h after pMCAO. Cresyl violet, Fluoro-Jade C staining, and immunohistochemical for GFAP, TNF-α, and iNOS were also carried out. The treatment with boldine significantly decreased the infarct area, improved the neurological scores, and increased cell viability. The vertical exploratory activity and aversive, spatial, object recognition, and working memory deficits induced by pMCAO were prevented by boldine. Moreover, myeloperoxidase activity and GFAP, TNF-α, and iNOS immunoreactivity were decreased significantly by boldine. Although various mechanisms such as its antioxidant activity should be considered, these results suggest that the neuroprotective effect of boldine might be related in part to its anti-inflammatory properties.

Neuroinflammatory response to experimental stroke is inhibited by eriodictyol.

BACKGROUND: Cerebral ischemia is a common disease and one of the most common causes of death and disability worldwide. The lack of glucose and oxygen in neuronal tissue leads to a series of inflammatory events, culminating in neuronal death. Eriodictyol is a flavonoid isolated from the Chinese herb Dracocephalum rupestre that has been proven to have anti-inflammatory properties. HYPOTHESIS/PURPOSE: Thus, the present study was designed to explore whether eriodictyol has neuroprotective effects against the neuronal damage, motor and memory deficits induced by permanent middle cerebral artery occlusion (pMCAO) in mice. STUDY DESIGN: Animals were orally treated with eriodictyol (1, 2 and 4mg/kg) or vehicle (saline) 30min before pMCAO, 2h after, and then once daily for the following five days. METHODS: The parameters studied were neuronal viability, brain infarcted area; sensorimotor deficits; exploratory activity; working and aversive memory; myeloperoxidase (MPO) activity; TNFα, iNOS and GFAP immunoreactivity. RESULTS: The treatment with eriodictyol prevented neuronal death, reduced infarct area and improved neurological and memory deficits induced by brain ischemia. The increase of MPO activity and TNF-α, iNOS and GFAP expression were also reduced by eriodictyol treatment. CONCLUSION: These findings demonstrate that eriodictyol exhibit promising neuroprotection effects against the permanent focal ischemia cerebral injury in the mice experimental model and the underlying mechanisms might be mediated through inhibition of neuroinflammation.

Rosmarinic acid prevents against memory deficits in ischemic mice.

Polyphenols have neuroprotective effects after brain ischemia. It has been demonstrated that rosmarinic acid (RA), a natural phenolic compound, possesses antioxidant and anti-inflammatory properties. To evaluate the effectiveness of RA against memory deficits induced by permanent middle cerebral artery occlusion (pMCAO) mice were treated with RA (0.1, 1, and 20mg/kg/day, i.p. before ischemia and during 5 days). Animals were evaluated for locomotor activity and working memory 72 h after pMCAO, and spatial and recognition memories 96 h after pMCAO. In addition, in another set of experiments brain infarction, neurological deficit score and myeloperoxidase (MPO) activity were evaluates 24h after the pMCAO. Finally, immunohistochemistry, and western blot, and ELISA assay were used to analyze glial fibrillary acidic protein (GFAP), and synaptophysin (SYP) expression, and BDNF level, respectively. The working, spatial, and recognition memory deficits were significantly improved with RA treatment (20mg/kg). RA reduced infarct size and neurological deficits caused by acute ischemia. The mechanism for RA neuroprotection involved, neuronal loss suppression, and increase of synaptophysin expression, and increase of BDNF. Furthermore, the increase of MPO activity and GFAP immunireactivity were prevented in MCAO group treated with RA. These results suggest that RA exerts memory protective effects probably due to synaptogenic activity and anti-inflammatory action.

Valproic Acid Neuroprotection in the 6-OHDA Model of Parkinson's Disease Is Possibly Related to Its Anti-Inflammatory and HDAC Inhibitory Properties.

Parkinson's disease is a neurodegenerative disorder where the main hallmark is the dopaminergic neuronal loss. Besides motor symptoms, PD also causes cognitive decline. Although current therapies focus on the restoration of dopamine levels in the striatum, prevention or disease-modifying therapies are urgently needed. Valproic acid (VA) is a wide spectrum antiepileptic drug, exerting many biochemical and physiological effects. It has been shown to inhibit histone deacetylase which seems to be associated with the drug neuroprotective action. The objectives were to study the neuroprotective properties of VA in a model of Parkinson's disease, consisting in the unilateral striatal injection of the neurotoxin 6-OHDA. For that, male Wistar rats (250 g) were divided into the groups: sham-operated (SO), untreated 6-OHDA-lesioned, and 6-OHDA-lesioned treated with VA (25 or 50 mg/kg). Oral treatments started 24 h after the stereotaxic surgery and continued daily for 2 weeks, when the animals were subjected to behavioral evaluations (apomorphine-induced rotations and open-field tests). Then, they were sacrificed and had their mesencephalon, striatum, and hippocampus dissected for neurochemical (DA and DOPAC determinations), histological (Fluoro-Jade staining), and immunohistochemistry evaluations (TH, OX-42, GFAP, TNF-alpha, and HDAC). The results showed that VA partly reversed behavioral and neurochemical alterations observed in the untreated 6-OHDA-lesioned rats. Besides, VA also decreased neuron degeneration in the striatum and reversed the TH depletion observed in the mesencephalon of the untreated 6-OHDA groups. This neurotoxin increased the OX-42 and GFAP immunoreactivities in the mesencephalon, indicating increased microglia and astrocyte reactivities, respectively, which were reversed by VA. In addition, the immunostainings for TNF-alpha and HDAC demonstrated in the untreated 6-OHDA-lesioned rats were also decreased after VA treatments. These results were observed not only in the CA1 and CA3 subfields of the hippocampus, but also in the temporal cortex. In conclusion, we showed that VA partly reversed the behavioral, neurochemical, histological, and immunohistochemical alterations observed in the untreated 6-OHDA-lesioned animals. These effects are probably related to the drug anti-inflammatory activity and strongly suggest that VA is a potential candidate to be included in translational studies for the treatment of neurodegenerative diseases as PD.