Neurodegenerative Potential of the Aqueous Leaf Extract of Ocimum gratissimum: A Histological and Biochemical Study

Abstract

Ocimum gratissimum is an herbaceous perennial shrub which is widely distributed in many regions. It is consumed in food as seasoning locally in Nigeria. In the present study, the effect of the acute administration of the aqueous leaf extract of Ocimum gratissimum (AeOG) on prefrontal cortical neurons was checked to assess its neurotoxicity potential. Thirty adult male Wistar rats weighing between 190-210 g were divided into 5 groups (n=6). Group A (control) received 1 ml of normal saline (p.o), groups B-E received 100, 200, 300 and 400 mg/kg AeOG (p.o) respectively. Treatment lasted for fourteen days. Twenty-four hours after treatment, animals were sacrificed and their brains were removed. The prefrontal cortices neuronal morphology was studied using haematoxylin and eosin (H&E) stain; while activities of acid phosphatase (ACP) and alkaline phosphatase (ALP) were assayed in the cerebral homogenate. AeOG administration at doses 300 and 400 mg/kg cause neuronal fragmentation and central chromatolysis with significant (P<0.05) increases in the activities of cerebral ACP and ALP. Our findings show that the acute use of AeOG caused neuronal fragmentation and central chromatolysis which are response to axonal injuries and may leads to onset of neurodegenerative diseases and affect cognitive and executive functions of the prefrontal cortex.

Keywords: Ocimum gratissimum, Acid Phosphatase (ACP), Alkaline Phosphatase (ALP), Neurogenerative diseases, Rat