Morphologic alterations on red blood cells labeled with technetium-99m: the effect of Mentha crispa L. (hortela) extract

The use of natural products, as medicinal plants, is very frequent in the world. Mentha crispa L. (M. crispa) is utilized in herbal medicine. Blood elements labeled with technetium-99m (99mTc) are used in nuclear medicine procedures and this labeling process may be altered by drugs. We have investigated the possibility of M. crispa extract being capable to alter the labeling of blood elements with 99mTc. Blood was incubated with M. crispa extract in various concentrations (6.25, 12.5, 25, 50 and 100%). Stannous chloride solution and Tc-99m, as sodium pertechnetate, were added. Blood was centrifuged and plasma (P) and blood cells (BC) were isolated. Samples of P and BC were also precipitated, centrifuged and insoluble (IF) and soluble (SF) separated. The percentage of radioactivity (%ATI) in BC, IF-P and IF-BC was calculated. Histological evaluations of the red blood cells (RBC) were performed with blood samples treated with various concentrations of M. Crispa L. and the morphology of the RBC was observed under optical microscope. Important morphological alterations expressed by mean of the perimeter/area of the RBC treated with M. crispa: 6.25% (0.67 ± 0.02), 12.5% (0.77 ± 0.03), 25% (0.73 ± 0.04), 50% (0.76 ± 0.04), 100% (0.69 ± 0.08) and the control cells (0.67 ± 0.05). The %ATI decreased: (i) on BC from 97.3 ± 1.92 to 60.0 ± 2.44; (ii) on IF-P from 74.8 ± 3.78 to 9.99 ± 3.61; (iii) on IF-BC from 88.6 ± 5.41 to 58.4 ± 11.55. The perimeter/area of the RBC showed significant differences (P>0.01) when compared 6.25% and 12.5%, and when compared 6.25% and 50% of M. Crispa L. extract. These findings could also justify the decrease of the labeling of BC with 99mTc in presence of M. Crispa extract