Investigations covered the possible hematotoxic effect of eugenol in rats
following two-week and four-week continuous p.o. application. An experiment
was conducted on 72 maleWistar rats divided into six groups. Four groups were
treated with different doses of eugenol (10 mg/kg bm/day, 50 mg/kg/day, 200
mg/kg/day and 400 mg/kg bm/day), the control group was administered a
vehiculum (0,5 % methylcellulose, 20 % propylene glycol and water), and the
sixth group was the absolute untreated control. Eugenol and the vehiculum
were administered using a gastric probe in a volume of 1 ml/100 g body mass
of rat. Blood was sampled using cardiac puncture on days 14 and 28 of the
experiment in order to determine hematological parameters (hematocrit, number
of erythrocytes, MCV, haemoglobin concentration, MCH, number of leukocytes,
leukocyte formula, and number of thrombocytes). The results have shown that
eugenol administered over 14 and 28 days in doses of 10, 50, 200 i 400 mg/kg
bm/day has no hemolytic activity. Furthermore, administered over four weeks,
it does not significantly affect the number of erythrocytes, haemoglobin
concentration, hematocrit, erythrocyte volume, number of leukocytes, and the
leukocyte formula. Applied over two weeks, eugenol causes a significant
increase in the mass of haemoglobin per erythrocyte, in comparison with
controls. This effect is non-specific and does not depend on the dose or on
the duration of treatment. The eugenol doses of 10 and 200 mg/kg/day
administered over a period of four weeks result in a statistically
significant reduction in the number of thrombocytes in comparison with the
absolute control, while the highest investigated dose (400 mg/kg) causes a
significant increase in comparison with the numbers for rats treated with a
dose of 10 and 200 mg/kg/day. The changes in thrombocyte number caused by
eugenol are qualitatively different and depend neither on the dose nor on the
duration of treatment. Eugenol applied over two or four weeks does not
exhibit a significant influence on the number of lymphocytes, monocytes or
granulocytes.