Tissue correlation of nitrite in plant parts of cassava (manihot esculenta crantz) and nitrosamine toxicity in wistar rat


John Uyinmwen Bazuaye, Emmanuel Ndubisi Maduagwu, Babatunji Emmanuel Oyinloye

Aim: This study was designed to determine the correlation in nitrite content of cassava (Manihot esculenta Crantz) as present in the various parts (roots, stems and leaves) and the possible hepatotoxicity when Wistar rats are exposed to N-nitrosamine precursors. Methods: Cassava cultivar used for this experiment was collected from International Institute of Tropical Agriculture, Ibadan, Nigeria (IITA). Various parts (Roots, Stems and Leaves) was weighed and homogenized separately. The homogenate was filtered to get clear solution and nitrite content therein was analyzed. Thirty Wistar rats divided into three groups, classified into; Group 1, Group 2 and Group 3 were used for the in-vivo experiment. The urine nitrite content and serum biomarkers of toxicity namely; Serum alanine transaminase (ALT), aspartate transaminase (AST), alkalin phosphatase (ALP) and gamma-glutamyl transferase (GGT) was estimated and the histopathological changes in the liver was examined in order to evaluate the extent of toxicity. Results: The nitrite levels in the roots, stems and leaves of these cassava cultivars were estimated as follows: roots; 110.8±23.7 µg/50 g, stems; 14.4±17.7 µg/30 g and leaves; 112.0±30.4 µg/5 g. The nitrite correlations between the roots and leaves is r = 0.97, correlations between the roots and stems is r = 0.65 while the correlations between the stems and leaves is r = 0.63. Urinalysis test carried out shows urine is the major sources of excretion of N-nitrosamines from the system. Both Group II and Group III animals had a significant increase in ALT, AST, ALP and GGT levels in t he serum. Histopathology study of liver is in agreement with these results. Conclusion: This study shows that there was a correlation in nitrite levels between the roots and leaves of cassava and the level of toxicity found in the liver of rat administer with N-nitrosamine precursors (DMA.HCL and NaNO2 ).