Behavioral and Biochemical Indices of Neurotoxicity in Jimson weed Administered Rats

Abstract

This study examined the effect of alkaloid extracts from leaf and fruit of Jimson weed (Datura stramonium L; a toxic food contaminant of global reputation) on cognitive function, antioxidant status and activities of critical enzymes of monoaminergic and cholinergic systems of neurotransmission in rats. Alkaloid extracts were prepared by solvent extraction method. The gas chromatograph coupled with mass spectroscopic (GC-MS) characterization of the extracts was also carried out. Thereafter, rats were administered 100 and 200 mg/kg body weight (p.o) of extracts for thirty days. Prior to termination of the experiment, the rats were subjected to spontaneous alternation and hole-board behavioral tests. Thereafter, rats were sacrificed and activities of acetylcholinesterase (AChE), monoamine oxidase (MAO) and antioxidant enzymes (superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase), as well as malondialdehyde (MDA) and total thiol (TSH) contents of their brain homogenates were determined. The results showed that rats administered the extracts exhibited reduced memory index and also exhibited increased level of anxiety-like behavior. Furthermore, rats administered the extracts exhibited significantly reduced levels of brain AChE, MAO, SOD, catalase and GST activities, reduced amount of brain TSH and elevated brain MDA content compared to control. Results from the GC-MS characterization revealed the presence of hyoscyamine (atropine), scopolamine, amphetamine, cathine, phenlyephirine and Tropine trifluoroacetate among others in the extracts. Therefore, the alterations in cholinergic, monoaminergic and antioxidant systems in brain of rats administered fruit and leaf alkaloid extracts of Jimson weed could be one of the major biochemical mechanisms underlying their ability to induce impairment of cognitive functions which could be significantly linked to their constituent alkaloids.