Biol. Pharm. Bull. 28(3) 490—494 (2005)

affects the developing central nervous system. Exposure to low levels of Pb has been associated with behavioral abnormalities, learning impairment, decreased hearing, and impaired cognitive functions in humans and in experimental animals. Experimental evidence suggests that cellular damage mediated by free radicals can be involved in the pathology associated with Pb intoxication. In erythrocytes from workers exposed occupationally to Pb, the activities of the antioxidant enzymes superoxide dismutase and glutathione peroxidase were significantly higher than in nonexposed workers. Blood levels of malondialdehyde (MDA), a product of lipid oxidation, were strongly correlated with blood Pb concentrations in exposed workers with Pb concentrations higher than 35 mg/dl. Various studies have shown that lead exposure can cause changes in catecholaminergic functions. CaNa2 EDTA is a traditional lead expellent but it is toxic to the liver and kidneys. Therefore recently there have been many studies on the use of natural agents such as vitamins and herbal drugs to expel lead. In recent years, the clinical importance of herbal drugs has received considerable attention. As many synthetic antioxidants have been shown to have one or the other side effects, there has been an upsurge of interest in the therapeutic potential of medicinal plants as antioxidants in reducing free radical-induced tissue injury. Numerous plant products have been shown to have antioxidant activity, and the antioxidant vitamins, flavonoids, and polyphenolic compounds of plant origin have been extensively investigated as scavengers of free radicals and inhibitors of lipid peroxidation. Seabuckthorn (Hippophae rhamnoides L.; HRL) is a Euro-Asian wild, newly cultivated, edible berry with exceptionally high contents of nutrients and phytochemicals such as lipids, waterand fat-soluble vitamins, and flavonoids. The ripe fruit has been reported to be a rich source of vitamins A, C, E, and K, carotenoids, and organic acids. The berries have a long history of application (more than 1000 years) in Tibetan and Mongolian medicine in the treatment of various diseases. A wide spectrum of positive physiologic effects of the berries and berry products have been suggested in animal experiments and clinical investigations. However, no study has reported the effects of HRL on lead-induced neurotoxicity. The deficits in learning and memory in Pb-exposed rodents are accompanied by damage to neurons and changes in some neurotransmitters, such as the cholinergic and catecholamine neurotransmitter system, are involved. Because oxidative damage is also involved in Pb toxicity, we examined parameters of oxidative stress in the brain from mice chronically exposed to the metal. In this study, we used behavioral and neurochemical experiments to determine the protective effects of HRL against the neurotoxicity induced by lead.