Aloysia gratissima prevents cellular damage induced by glutamatergic excitotoxicity Ana L. B. Zeni a,c , Samuel Vandresen-Filho a,d , Tharine Dal-Cim a , Wagner C. Martins a , Daniela B. Bertoldo a , Marcelo Maraschin b and Carla I. Tasca a Departments of a Biochemistry, Biological Sciences Center, b Plant Morphogenesis and Biochemistry Laboratory, Plant Science Center, Federal University of Santa Catarina, Florianópolis, c Department of Natural Sciences, Natural and Exact Sciences Center, Regional University of Blumenau, Blumenau, Santa Catarina, d Department of Basic Sciences in Health, Federal University of Mato Grosso, Cuiabá, Mato Grosso, Brazil Keywords Aloysia gratissima; cell viability; ferulic acid; neuroprotection; quinolinic acid Correspondence Ana L. B. Zeni, Departamento de Ciências Naturais – Universidade Regional de Blumenau – Campus I, Blumenau, 89012-900 Santa Catarina, Brazil. E-mail: anazeni@furb.br Received November 19, 2013 Accepted March 2, 2014 doi: 10.1111/jphp.12250 Abstract Objectives Aloysia gratissima aqueous extract (AE) was investigated as a putative protective agent against quinolinic acid (QA)-induced seizures in mice and hippocampal cell damage. Additionally, AE and ferulic acid (FA), the major com- pound of AE, were tested against neurotoxicity evoked by glutamate or its N-methyl-D-aspartate receptor (NMDAR) agonist, QA on hippocampal slices, in vitro. Methods Mice were treated with AE before QA infusion (36.8 nmol/site) and sei- zures were analysed. Cellular viability and modulation of excitatory amino acid transport were verified in hippocampal slices. In-vitro AE or FA was tested against neurotoxicity induced by glutamate or QA. Key findings AE did not prevent QA-induced seizures; however, it prevented cel- lular death and disruption of excitatory amino acid transport. In-vitro AE (0.1 or 1.0 mg/ml) or FA (1 or 10 μm), improved cell viability against citotoxicity exerted by glutamate or QA, respectively. Both AE and FA have protective effects depend- ing on activation of the phosphatidylinositol-3 kinase (PI3K) signalling pathway. Conclusions AE attenuated QA-induced cell damage possibly involving the glutamate transport modulation through NMDAR interaction. FA shows a similar profile of neuroprotection promoted by AE. Therefore, AE treatment might be a useful strategy in preventing brain damage caused by exacerbation of glutamatergic toxicity in nervous system disorders. Introduction Exacerbation of the glutamatergic transmission is an event involved in neuropathological processes such as seizures, ischaemia, traumatic brain injury and chronic neuro- degenerative diseases. [1] Quinolinic acid (QA; 2,3-pyridine dicarboxylic acid) is a convulsant agent that is known as an N-methyl-D-aspartate receptor (NMDAR) agonist that causes excitotoxicity through elevation of cytosolic concentrations of calcium, ATP exhaustion and free radical formation. [2] Additionally, QA has been shown to over- stimulate the glutamatergic system through modulation of glutamate transport, by decreasing glutamate uptake into synaptic vesicles or astrocytes in culture and increasing the synaptosomal release of glutamate to the extracellular space. [3,4] Intracerebroventricular (i.c.v.) administration of QA is known to induce tonic–clonic seizures [5] which are followed by a necrotic pattern of neural cell death, [6] clearly observed in hippocampal slices ex vivo. [7] Neuroprotection following status epilepticus should encompass not only the preven- tion of neuronal death, but also preservation of neuronal and network function. [8] Therefore, the search for new anticonvulsants and neuroprotective agents obtained from natural products is a matter of intense basic sciences and clinical investigation. Aloysia gratissima (Gill et Hook) Troncoso (erva-santa) belongs to the Verbenaceae family and it is a plant that has been commonly used to alleviate symptoms associated with headache, bronchitis and nervous system disorders. [9–12] A. gratissima aqueous extract (AE) has recently been docu- mented by our group for its antidepressant-like and neuroprotective effects. [13] Furthermore, AE has been shown to be a safe extract to administer in vivo, and its chemical And Pharmacology Journal of Pharmacy Research Paper © 2014 Royal Pharmaceutical Society, Journal of Pharmacy and Pharmacology, 66, pp. 1294–1302 1294 Downloaded from https://academic.oup.com/jpp/article/66/9/1294/6127946 by guest on 20 June 2022