The primary aimed of this study was to investigate the potential protective effects of methanolic extract of
citrus peel (MECP) on acute cyanide (KCN) poisoning-induced seizures and oxidative stress in rats. The intraperitoneal
LD50 value of KCN (6.3 mg/Kg bwt), based on 24 hrs mortality, was significantly increased by 9, 52 or 113% by oral
administration of MECP (500 mg/Kg bwt) pre-administered for 1, 2 and 3 days, respectively, in rats in a time-dependent
manner. Intraperitoneal injection of the sublethal dose of KCN (3 mg/Kg bwt) into rats increased, 24 hrs later, lipid
peroxidation (LPO), nitric oxide (NO), glutamate levels and acetylcholinesterase (AChE) activity in hippocampus,
striatum and cerebral cortex. KCN also decreased brain glutathione (GSH) level and superoxide dismutase (SOD) and
catalase (CAT) activities in these animals. Pre-treatment of rats with MECP inhibited KCN-induced increases in LPO,
NO, and glutamate levels and AChE activity as well as decreases in brain GSH level and SOD and CAT activities. In
addition, KCN significantly decreased norepinephrine, dopamine and serotonin levels in different brain regions which
were resolved by MECP. From the present results, it can be concluded that the neuroprotective effects of MECP against
KCN-induced seizures and oxidative stress may be due to the inhibition of oxidative stress overproduction and
maintenance of antioxidant defense mechanisms.
Antioxidants, citrus peel, oxidative stress, potassium cyanide, seizures.
Department of Zoology and Entomology, Faculty of Science, Helwan University, 11795 Helwan, Cairo, Egypt.