Preventive Effect of the Extract of Du-Zhong (Tochu) Leaf and Ginseng Root on Acute Toxicity of Chlorpyrifos.

Abstract

The preventive effects of the extract (DP-extract) prepared from leaves of Eucommia ulmoides OLIVER, Eucommiaceae (Du-Zhong leaf) and roots of Panax ginseng C.A. MEYER (Ginseng), which are widely used as healthful teas, on acute toxicity of chlorpyrifos, a common organophosphorus insecticide, were investigated in mice. A 50% lethal dose of chlorpyrifos was 16.9% higher in the group pretreated with DP-extract for 3 weeks (6.66 g of dried leaves and root/kg/d, p.o.) than in the chlorpyrifos alone group. Cholinesterase (ChE) activities in serum were higher and the residual chlorpyrifos in liver was lower in mice pretreated with DP-extract than in the chlorpyrifos-alone group. Hepatic cytochrome P450 content, activities of NADPH-cytochrome c reductase and carboxylesterase (EC3.1.1.1) in livers of DP-extract pretreated mice were significantly higher than those of untreated control immediately after chlorpyrifos injection. The activities of those enzymes were also significantly higher in the DP-extract pretreated mice than the controls. Northern blot analysis of microsomes from livers of DP-extract pretreated mice revealed the increased transcription of NADPH-cytochrome c reductase and carboxylesterase. These results suggest that DP-extract increased the activities of cytochrome P450 and carboxylesterase and accelerated detoxification of chlorpyrifos to prevent the acute toxicity of the organophosphorus insecticide.