Toxic effects of croton magalocarpus seed oil on mice
Kamotho, Lucy Wanjeri
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This project was carried out in Zoology Department Kenyatta University. The objectives of this study were: i. to establish the Lethal Dose (LD50) OF Croton megalocarpus seed oil on mice. ii. to establish the long-term toxicity of the oil on mice. iii. to find out the effect of the toxic substances in the oil on tissues on mice. Croton megalocarpus seed oil was obtained from the Chemistry Department, Kenyatta University. The experimental animals that were used were mice (Mus species, MF1). Adults of both sexes (males and females) were mixed up in the cages to allow normal breeding and interaction to take place. The mice were injected with different doses of the oil 84, 168, 252, 336 and 420 mg (per 30g of body weight) in order to establish LD50. Percent mortality was recorded for each group and this was transformed into probit values, which were plotted against Logarithm to base ten of concentration of the corresponding doses. The LD50 value was then obtained by use of by use of Least Square method (regression) and the dose that killed 50% of the test mice population was found to be 10.0067 x 104 mg/kg of mouse body weight. Lower doses (8.4, 16.8, 25.2, 36.6 and 42.0 mg/30g of mouse body weight) were used on another set of mice. The weights of these mice were not affected and no deaths were observed. Red and white blood cell counts were done. The total erythrocyte counts did not differ significantly in the long-term as well as in short-term toxicity studies with respect to the dose levels, (P>0.05). The total leucocyte counts differed significantly with respect to doses (P<0.01). Death in animals injected with Croton oil was not due to anaemia since there was no reduction in erythrocyte counts. Lymphocytes in the short-term study differed significantly (P<0.01) while neutrophils, eosinophils, basophils and monocytes did not significantly differ in numbers with respect to the doses used. As the dose of Croton oil administered increased, more lymphocytes were being recruited into the tissues. Histopathological studies revealed that toxic effects occurred in tissues of spleen and liver. A huge infiltration of mononuclear cells occurred in the spleen. This was followed by degeneration of kupffer cells. Cellular hyperplasia and hypertrophy were observed in the spleen. Autopsy revealed degeneration and appearance of huge dots both inside and outside the cells. The liver smear revealed that liver macrophages were being affected by the oil although there was no evidence of tissue hyperplasia. There were vacuoles in some macrophages, and dark granular droplets were observed within the cytoplasm. No basophilia was observed suggesting that death of the animals was not due to anaphylactic shock. There was no evidence of increase in mast cell production, which would release vasoactive agents. Examination of the heart revealed no blood clot, suggesting death was not due to thrombosis or passive hyperaemia.
- MST-Zoological Sciences