Garcinia kola prevents scopolamine-induced memory impairment in mice: Role of oxidative and nitrosative stress
Ismail O. Ishola , Wahab O. Okunowo , Gbenga O. Afolayan, Azeezat A. Awoyemi
1Department of Pharmacology, Therapeutics and Toxicology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, PMB 12003, Idi-araba, Lagos, Nigeria.
2Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, PMB 12003, Idi-araba, Lagos, Nigeria.
Corresponding author : Ismail Ishola
Email add: oishola@cmul.edu.ng Phone : +2348033018908
ABSTRACT
Background: The high and increasing incidence of Alzheimer Disease (AD) worldwide is a major global concern. Oxidative stress has been considered to be linked to the aetiology of many diseases, including neurodegenerative diseases (NDDs) such as AD. Garcinia kola Heckel (Clusiaceae) has important antioxidant functions that can help protect against AD.
Objective: This study sought to investigate the protective effect of ethanol seed extract of Garcinia kola (GCK) on scopolamine-induced memory impairment in rodents.
Methods: GCK (25, 50 and 100 mg/kg, p. o.) or tacrine (5 mg/kg, i. p.) was administered for 3 consecutive days. Scopolamine (3 mg/kg, i. p.) was given, 1 h after last-treatment on day 3, followed by estimation of memory functions using the Y-maze and elevated plus maze (EPM) tasks in mice as well as Morris water maze test (MWM) in rats. The biochemical markers of oxidative stress were determined in the prefrontal cortex, hippocampus and striatum after the MWM test on day 8.
Results: Scopolamine induced significant decrease in spontaneous alternation behaviour in Y-maze and increased transfer latency in EPM in mice which was prevented by pretreatment of mice with GCK. In the MWM experiment, GCK protected rats against spatial learning deficit induced by scopolamine, evidenced in session dependent decrease in escape latency. Furthermore, scopolamine induced increased oxidative and nitrosative stress status in the prefrontal cortex, striatum and hippocampus as compared with vehicle-treated control was ameliorated with GCK administration which was similar to the effect of tacrine.
Conclusion: G. kola prevented scopolamine-induced cognitive impairment through attenuation of oxidative/nitrosative stress status. Thus, could be a potential phytotherapeutic agent in the treatment of dementia.
Keywords: Antioxidant system; hippocampus; Morris water maze; scopolamine; Y-maze