The Effect of Eucalyptus Oils on the Erythrocytes of Koalas
N. S. Agar1, E. Ogawa 1'2, S. S. O'Callaghan 1 and I. D. Hume3
1Department of Physiology, University of New England, Armidale, Australia;
2Department of Veterinary Medicine, Azabu University, Kangawa, Japan;
3School of Biological Sciences, University of Sydney, Australia
The oxidant effects of two fractions of eucalyptus oil; monoterpenes (C10) and the larger sesquiterpenes (C15), were investigated in the erythrocytes of the koala (Phascolarctos cinereus). The effects studied included the degree of haemolysis and changes in the intracellular levels of glutathione (GSH) and adenosine triphosphate (ATP) and in the membrane phospholipids. The results indicate that koala erythrocytes are susceptible to eucalyptus oil-induced oxidative damage. The two types of eucalyptus oils have different effects on the erythrocytes; monoterpenes appear to induce haemolysis through oxidative damage to the intracellular constituents, whereas sesquiterpenes may attack the red cell membrane.