Assessment of the Biological Effects of a Natural Extract of Equinacea Purpurea: An In Vitro Analysis

Medicinal plants have been widely used by human beings. However, sometimes the biological effects of these plants are not fully known. It is concerned that many natural medicines may contain potentially toxic ingredients and contaminants such as heavy metals. Red blood cells (RBC) and plasma proteins labeled with technetium-99m (99mTc) have several clinical applications and it has been reported that some natural products are capable of reducing the efficiency of this radiolabeling. Equinacea purpurea is a plant with medicinal properties. It is indicated to treatment of the inflammation in the respiratory system and in the skin. The aim of this work was to assess the effects of Echinacea purpurea on the labeling of blood elements with 99mTc. A freshly extract of E. purpurea (300 mg/10 mL) was administered to the aliquots of blood withdraw from Wistar rats during 1 hour. After that, samples (0.5 mL) of blood were incubated with stannous chloride (SnCl2) and 99mTc. The blood was centrifuged and plasma (P) and RBC were isolated. P and RBC were also precipitated with trichloroacetic acid and soluble (S) and insoluble (I) fraction (F) were determined. The results have shown that the referred extract was able to reduce the radiolabeling in BC to the concentrations of: 25% (from 93.09%±3.63 to 55.17%±7.85), 12.5% (from 93.09%±3.63 to 43.22%±3.92) and to the 6,25% (from 93.09%±3.63 to 35.15%±2.36). In the light of the results the referred extract has reduced the efficiency of.radiolabeling in the blood cells. We suggest that the extract may induce the generation of reactive oxygen species with oxidant properties with direct action on the labeling process. [Nature and Science, 2004,2(1):1-5].