Effect of crude extract and its semi purified constituents from guaraná seeds [Paullinia cupana var. sorbilis (Mart.) lucke] on cognitive performance in Morris water maze in rats

723 Vol.48, n. 5 : pp. 723-728, September 2005 ISSN 1516-8913 Printed in Brazil BRAZILIAN ARCHIVES OF BIOLOGY AND TECHNOLOGY A N I N T E R N A T I O N A L J O U R N A L Effect of Crude Extract and its Semi Purified Constituents from Guaraná Seeds [Paullinia Cupana Var. Sorbilis (Mart.) Lucke on Cognitive Performance in Morris Water Maze in Rats Fernanda Jacques Otobone, Andréia Conegero Sanches, Rosangela Lika Nagae, Juliana Vanessa Colombo Martins, Simoni Obici, João Carlos Palazzo de Mello and Elisabeth Aparecida Audi* Departamento de Farmácia e Farmacologia; Universidade Estadual de Maringá; Av. Colombo, 5790; zona 7; 87020-900; Maringá - PR - Brasil ABSTRACT The effect of crude lyophilized extract (EBPC) and the semi-purified constituents (EPA and EPB) of Paullinia cupana (guaraná) seeds long-term administered in rats by gavage at different doses was studied on cognitive behavior in rats. EBPC (30.0 mg/kg) and EPA (2.0 mg/kg), but not EPB (2.0 or 4.0 mg/kg) showed a smaller escape latency to find the emerged platform in Morris water maze test (MWMT), showing nootropic-like effect in normal rats, and in scopolamine induced amnesia rats compared to their controls (saline + 0.2% Tween 80) group. These extracts had no significant effect in open field test (OFT). Caffeine did alter escape latency in MWMT only in scopolamine induced amnesia rats and increased the crossings number in OFT, showing significant stimulant effect. Chronic treatment showed the same increase in body weight and average lifespan indicating a low toxicity for the extracts. Key words: Cognitive effects, guaraná, Morris water maze, Paullinia cupana INTRODUCTION In the recent years, there has been a rise in the interest of scientific community and pharmaceutical laboratories to explore the pharmacological actions of herbs. Several plants have been reported to posses nootropic activity (Nadkarni, 1996). Guaraná (Paullinia cupana var. sorbilis (Mart.) Ducke Sapindaceae) is a plant found in the central Amazon basin region in Brazil. Guaraná seeds contains high concentration of xanthic bases (3.0-6.0%) * as caffeine (1,3,7-trimethylxanthine), and trace amounts of theophylline and theobromine. It also contains high concentrations of polyphenols or saponines (7%) as flavan-3-ols [catechin and epicatechin] and other condensed tannins (Henman 1982, Benowitz, 1990). Guaraná has been popularly used as stimulant of the central nervous system (CNS) in cases of intelectual and physical stress, as antidiarrheic, diuretic and antineuralgic agent (Benowitz, 1990). The xanthic bases of guaraná, however, do not explain all of these therapeutic actions. Rats treated with extracts of guaraná, but not with caffeine at a dose similar to Author for correspondence Brazilian Archives of Biology and Technology 724 Otobone, F. J. et al. that found in guaraná extract, had shown antioxidant (Mattei et al, 1998) and anti-amnesia effects (Espinola et al, 1997) in a passive avoidance test. Thus, its effects could to be due to the other(s) substance(s) than xanthines contents in extract. Saponins and tannins are known as substances that have antioxidant action (Simeray et al, 1982; Yoshizawa et al, 1987). Saponins from Panax ginseng (Ying et al, 1994) and the total saponin isolated from red ginseng (Lee et al, 2000) are the active substances responsible for enhancing cognitive behavior. Despite of widespread there are only a few experimental data up to now avaliable describing the constituents responsible by the different popular uses. Thus, the aim of this work was to investigate the effects of the chronic treatment of the crude extract (EBPC) or of its semi purified (EPA and EPB) constituints from the seeds of Paullinia cupana (guaraná) on cognitive behavior in rats. The experimental model chosen were the Morris water maze (MWM). MATERIALS AND METHODS Plant material The guaraná seeds were collected near Maués, Amazonas State, Brazil. The samples were dried and stabilized using facilities provided by EMBRAPA. The dried seeds were ground using a grinder Tecnal (model TE-048). A voucher plant specimen (#PR9065) was deposited with the Herbarium of the State University of Maringá (HUM). Species identification was performed by Dr. Cássia Mônica Sakuragui. Extracts and drugs An extract was prepared from the seeds (1000 g) and after removal of the organic solvent, the remaining solid material was lyophilized (EBPC – patent pending # PI 0006638-9). The semipurified, lyophilized extracts were obtained from EBPC (158 g): EPA (44 g) and EPB (53 g) (patent pending # PI 0006638-9). EBPC (30.0 or 60.0 mg/kg), EPA (2.0 or 4.0 mg/kg) and EPB (2.0 or 4.0 mg/kg) extracts were solubilized and administered by gavage in rats. Caffeine (10.0 mg/kg, Sigma) and scopolamine (2.0 mg/kg, Sigma) were administered by intraperitoneal (i.p.) rout. The control group was treated with the vehicle used to dissolve all solutions used (0.9% NaCl containing 0.2% Tween 80). Animals Male Wistar rats (50-55 days old, 220-250 g) housed 5 per cage constant room temperature (2223 °C) under a 12 h light-dark cycle with free access to food and water were used in the experiments. The animals were treated once daily for 40 days with the crude extract EBPC, EPA or EPB. The procedures adopted were approved by the UEM Ethical Committee (# 084-02/COBEA) and followed by the norms recommended as international guiding principles for Biomedical Research Involving Animals (CIMS), Geneva, 1985. Morris water maze test (MWMT) A spatial memory was performed by the method of Morris (1984). The test consisted of a round water tank (150 cm in diameter X 40 cm in height) with opaque water (25 cm in height) containing a temperature of about 22 ± 1 °C. The pool was placed in a room with fixed furniture and posters able to function as extramaze cues. The maze was divided into four equal quadrants (south-west, north-west, nort-est, south-east). A incolor glass platform (23.5 cm height and apical diameter of 8 cm) was placed 1 cm below the water surface, always midway between the center and rim of the pool in the target quadrant, so that it was invisible at the water surface. Rats were trained to find the hidden platform at a fixed location in space. The parameter evaluated was the latency to find the platform (escape latency). On the first day, the rats were given five trials sessions of 2 min. with a inter-trial interval of 30 min. In each trial, once the rats found the platform and rested upon it, they were permitted to remain for 30 s. If the rat did not find the platform within the maximal time, it was placed on it for 30 s and then removed from the pool. The escape latency was stabilized between 3–5 trial sessions, when the rats learned to take relatively direct paths to the hidden platform. The escape latency was not averaged in the trial sessions. At 24 h, the rats were submitted to a test session to evaluate the spatial retention memory. The test session had a maximal time of (...truncated)