RESUMO
The excessive consumption of alcohol affects the central nervous system, resulting in memory and learning deficits. Lutein is a carotenoid known for its antioxidant properties, which can be able to prevent neurodegenerative diseases and cognitive deficits. In the present study, we evaluated the effect of lutein on ethanol-induced memory deficits in the object recognition task in adult rats, as well as the possible involvement of oxidative stress and cholinergic system. Wistar rats were randomly divided into two groups receiving lutein (50â¯mg/kg) or olive oil (1â¯mL/kg) by oral gavage once daily for 14â¯days. On day 8 each group was divided again into two groups receiving either ethanol (3â¯g/kg) or saline by oral gavage once daily for 7â¯days. After the last administration, the animals were submitted on the object recognition task 24â¯h later (on days 15, 16 and 17). After the behavioral test, the hippocampus and cerebral cortex were removed for the determination of oxidative stress indicators (superoxide dismutase, thiobarbituric acid reactive substances, and non-protein thiol) and acetylcholinesterase activity. Ethanol administration induced a memory deficit and increased acetylcholinesterase activity, however, it did not alter the parameters of oxidative stress, evaluated in the cortex and hippocampus. Oral administration of lutein (50â¯mg/kg during 14â¯days) attenuated memory deficit and the increase of acetylcholinesterase activity induced by ethanol. These results provide evidence that lutein is an alternative treatment for ethanol-induced memory deficit, and suggest the involvement of cholinergic system.
Assuntos
Acetilcolinesterase/metabolismo , Antioxidantes/farmacologia , Depressores do Sistema Nervoso Central/antagonistas & inibidores , Depressores do Sistema Nervoso Central/toxicidade , Etanol/antagonistas & inibidores , Etanol/toxicidade , Luteína/farmacologia , Transtornos da Memória/prevenção & controle , Animais , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/enzimologia , Hipocampo/efeitos dos fármacos , Hipocampo/enzimologia , Masculino , Transtornos da Memória/induzido quimicamente , Estresse Oxidativo/efeitos dos fármacos , Desempenho Psicomotor/efeitos dos fármacos , Ratos , Ratos Wistar , Reconhecimento Psicológico/efeitos dos fármacosRESUMO
Lutein is a xanthophyll carotenoid widely known by its biological properties and low toxicity. When located in the brain, lutein may inhibit damage mechanisms, acting in neural cells maintenance. However, this carotenoid is very sensitive to external agents such as heat, light, pH and oxidation, besides presenting low absorption in gastrointestinal tract due its low solubility in water. Encapsulation procedures have shown promising results to increase lutein stability and bioavailability. In this work, lutein was encapsulated in polyvinylpyrrolidone (PVP) matrix by the dissolution in common solvent method. Nanoparticles were characterized in respect to morphology, water solubility, and interactions between PVP and lutein. In vivo tests were carried out in order to investigate the influence of lutein encapsulation on mice's declarative memory. Ex vivo tests were also carried out to determine if nanoparticles may cause any inflammatory process per se. Results indicated that lutein was successfully encapsulated in PVP while nanoparticles presented spherical shape and uniform size. Encapsulation was able to increase water solubility of lutein by more than 43 times, which may be attributed to the formation of soluble complexes trough hydrogen bonds between lutein hydroxyl group and PVP carbonyl group. In vivo studies showed that the administration of free lutein at 100mg·kg-1 and lutein-loaded PVP nanoparticles at 10 and 1.5mg·kg-1 significantly increased mice's object recognition index, meaning that significant lower doses of lutein were needed to achieve the same effect when lutein was encapsulated. Ex vivo studies showed that lutein-loaded nanoparticles administration did not alter inflammatory parameters in plasma, liver and brain of mice. In this sense, lutein-loaded PVP nanocapsules showed to be an advantageous alternative to increase water solubility and to improve the memory of mice without causing inflammatory damage per se.
Assuntos
Nanopartículas , Animais , Disponibilidade Biológica , Luteína , Camundongos , Povidona , SolubilidadeRESUMO
Lutein is a carotenoid presenting known anti-inflammatory and antioxidant properties. Lutein-rich diets have been associated with neurological improvement as well as reduction of the risk of vision loss due to Age-Related Macular Degeneration (AMD). Micro and nanoencapsulation have demonstrated to be effective techniques in protecting lutein against degradation and also in improving its bioavailability. However, actual lutein concentration inside the capsules and encapsulation efficiency are key parameters that must be precisely known when designing in vitro and in vivo tests. In this work an analytical procedure was validated for the determination of the actual lutein content in zein nanoparticles using ultraviolet-visible spectroscopy. Method validation followed the International Conference on Harmonisation (ICH) guidelines which evaluate linearity, detection limit, quantification limit, accuracy and precision. The validated methodology was applied to characterize lutein-loaded nanoparticles.