Nutritional qualities of vegetables, Vernonia amygdalina; Amaranthus caudatum and Telfairia occidentalis, were evaluated along with the cytotoxic effects of their aqueous extracts to ascertain the potential risk that may be associated with the consumption of vegetables from unknown sources. Leaves of the plants were used for proximate analysis, while microscopic and macroscopic tests of the aqueous extracts of each of the vegetables were conducted using 0.25, 0.5, 1.0, 2.5, 5.0, 10.0, 25.0 and 50.0 ppt. Physicochemical parameters of the water used in extract preparation and heavy metals of the extracts were also analyzed. Proximate analysis revealed no significant difference in protein, fibre and moisture content of the vegetables. However, ash content in T. occidentalis was significantly different from other vegetables while carbohydrate in V. amygdalina and A. caudatum were similar but different from the value of T. occidentalis. Variations were observed in the values of heavy metals with significant difference in the Fe, Zn and Cu values. Significant inhibitory effect was observed at 5.0, 10.0, 25.0 and 50.0 of all the extracts in addition to 2.5 ppt of V. amygdalina. The EC50 values of 8.0, 7.0 and 2.4 ppt were obtained for V. amygdalina, A. caudatum and T. occidentalis respectively which also indicate increasing order of inhibitory effects. Reduction in values of dividing cells and mitotic index of the treated onions were prominent at higher concentrations of the vegetable extracts. Chromosomal aberrations observed include chromosome bridge, laggard chromosome, vagrant chromosome and c- mitosis. The results revealed that the vegetables have high nutritional potential. However, bioaccumulation of toxicants reflects in their potential cytotoxicity on the Allium cepa roots. The data obtained in this study will create awareness for the consumer to know the sources of the vegetables before been purchased for consumption.
