APP and Cognitive impairment: CEF received group substantially enhanced the cognitive impairment in early stage of AD animals.  CEF (all the 3 doses) also upregulated GLT-1, glutamine synthetase (GS), and system N-glutamine transporter-1 (SN1) protein expressions in the hippocampus of APP/PS1 AD mice.  Dihydrokainate, a selective inhibitor of GLT-1 reversed enhanced memory functioning, GS activity, and SN1 expression of CEF in APP/PS1 AD mice.