Pathology of 2-alkyl and 2-hydroxy naphthoquinone toxicity in rats (abstract)

Authors: Munday R, Smith BL
Publication: New Zealand Veterinary Journal, Volume 43, Issue 3, pp 124, Jun 1995
Publisher: Taylor and Francis

Animal type: Rat, Rodent
Subject Terms: Parasites - external, Pathology, Pest/pesticides, Research/development, Toxicology
Article class: Abstract

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Abstract: The oral administration of 2-methyl-1, 4-naphthoquinone (menadione) to rats caused oxidative destruction of the erythrocyte. Heinz body formation occurred in erythrocytes, lowered PCVs and haemoglobin occurred in blood, with splenic and hepatic erythroclasis, and iron conservation in the spleen, liver and kidney. These effects diminished when increasingly large alkyl substitutions of the methyl group of the naphthoquinone were made. No effect was caused by the 2-decyl derivative.
In a further experiment, the oral toxicity of the 2-hydroxy derivative (the lawsone of henna) was compared with menadione in rats at dose rates up to 750 µmol/kg/day for 5 consecutive days. Like menadione, lawsone caused non-intravascular oxidative haemolytic anaemia. However, lawsone also caused renal enlargement, elevated plasma urea and creatinine and tubular nephrosis confined mainly to the S₃ distal segment of the proximal convoluted tubules. It is suggested that the renal injury is due to metabolism and the more soluble nature of the 2-hydroxy compound.

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