Study of tlie CJ>ossi6(e :Neuroprotective

Abstract

A large number of herbal medicines with therapeutic potential have been assessed using a variety of animal models. Their mechanisms of actions have been investigated through neurochemical approaches. These medicinal plants have provided useful information for the development of new pharmacotherapies for use in clinical psychiatry. The present study was constructed in order to investigate the

possible neuroprotective effects of thyme and ginger extracts in an animal model of dementia in rats. Dementia was induced in rats by i.p. injection of scopolamine

(20mg/kg) thirty minutes before submission to the active avoidance test. Six groups of animals were treated orally with vehicle, thyme extract in two doses (0.5 and I g/kg), ginger extract in two doses (I and 2g/kg) and donepezil (I Omg/kg) one hour before performing the active avoidance test. The average numbers of conditioned, unconditioned and failed avoidance responses were recorded for each group. Rats were sacrificed by decapitation immediately following the conditioned avoidance test; brains were isolated for estimation of ChE activity, NA, DA and 5-HT contents. In addition TAO and MDA brain contents were also estimated. Another group of animals received vehicle one hour before submission to the active avoidance test and saline (i.p.) thirty minutes before performing the test.