Abstract: The evidence that natural and synthetic drugs can affect radiolabeling or biodistribution of red cells in setting of nuclear medicine clinic has come to light only recently. A therapeutic drug can modify the nature/amount of technetium-99m (99mTc) radiopharmaceutical bound to blood elements and this may result in a unexpected behavior of the radiopharmaceutical. Once chayotte is used as food and also in folk medicine, we decided to evaluated the influence of this natural product on the labeling of blood elements with 99mTc and in the structural conformation of a plasmid pUC 9.1 trough gel electrophoresis analysis. Blood withdrawn from Wistar rats was incubated with the extract, (100% v/v).The blood samples were incubated with stannous chloride and with 99mTc. Plasma (P) and blood cells (BC) were isolated, also precipitated with trichloroacetic acid and soluble (SF) and insoluble fractions (IF) separated. A sample of blood was treated with ficoll-hypac, centrifuged and white cells were isolated. A solution of lymphocytes (2.5 mL) was obtained. After that, 0.2mL of a solution of lymphocytes was incubated with 0.1 mL of the vegetable extracts. A solution of stannous chloride and 99mTc were added. Lymphocytes and aqueous solution were separated. The %ATI bound to blood components was evaluated. The analysis of the results showed that there is not a decrease in %ATI in the blood constituents with chayotte extract. Although chayotte extract is not capable to alter the radiolabeling of. blood proteins and cells with 99mTc it was observed that the referred extract is capable to induce lesions in the plasmid DNA showing their possible oxidant properties. The studied natural product was not capable to oxide the stannous ions sufficiently to reduce the labeling of blood elements with 99mTc.
E. A. C. Lima , M. L. Gomes , S. Moreno , M. T. Q. Marques , R. L. Jales and M. Bernardo-Filho , 2004. An In vitro Study of a Natural Product (chayotte): An Analysis on the Labeling of Blood Components with Technetium-99m and on the Morphology of DNA . Journal of Food Technology, 2: 71-75.