Assessment of Biological Effects of Purpurea Extract

Abstract: 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 (SnCl 2 ) 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

Bioavailability of the sodium pertechnetate and morphometry of organs isolated from rats: study of possible pharmacokinetic interactions of a ginkgo biloba extract

Many compounds affect the bioavailability of radiobiocomplexes as radiopharmaceuticals. Ginkgo Biloba extract (EGb) has several effects. The influence of an EGb on the bioavailability of the radiobiocomplex sodium pertechnetate (Na99mTcO4) and on the morphometry of the organs was evaluated. Rats were treated with EGb and Na99mTcO4 was injected. The animals were sacrificed; the radioactivity in the organs was counted. The results showed that EGb altered the Na99mTcO4 bioavailability in the kidneys, liver and duodenum. Morphometric analysis of the organs showed significant alterations (P<0.05), probably caused by metabolites generated by EGb and capable of altering the bioavailability of the Na99mTcO4.<br>Substâncias podem interferir na biodisponibilidade de radiobiocomplexos, como os radiofármacos. O extrato de Ginkgo Biloba (EGb) apresenta efeitos. Avaliou-se a influência de um EGb na biodisponibilidade do pertecnetato de sódio (99mTcO-4Na) e na morfometria de órgãos de ratos que foram tratados com EGb. 99mTcO-4Na foi injetado, os animais sacrificados e a radioatividade nos órgãos contada. Os resultados mostraram que o EGb alterou a biodisponibilidade do 99mTcO-4Na em rins, fígado e duodeno e alterações morfométricas significativas (p<0.05) foram encontradas. Sugere-se que o EGb poderia gerar metabólitos capazes de alterar morfometricamente os órgãos citados e alterar a biodisponibilidade do 99mTcO-4Na

Uncaria tomentosa extract: evaluation of effects on the in vitro and in vivo labeling of blood constituents with technetium-99m

The influence (in vivo and in vitro) of an Uncaria tomentosa extract (Cats claw) on the labeling of red blood cells (RBCs) and plasma and cellular proteins with technetium-99m (Tc-99m) was evaluated. For the in vivo treatment, animals were treated with Cats claw. For the in vitro treatment, heparinized blood was incubated with Cats claw before the addition of stannous chloride (SnCl2) and Tc-99m. Samples of plasma (P) and RBCs were separated and also precipitated with trichloroacetic acid. The soluble and insoluble fractions of P and RBCs were isolated. The analysis of the results of the in vivo study, indicates that there is no significant alteration on the uptake of Tc-99m by the blood constituents, but it significantly decrease (p<0.05) the labeling of blood constituents by in vitro methods. These effects could be due to chelation of stannous and /or pertechnetate ions and blockage of the Tc-99m bindings sites.<br>O objetivo do presente estudo foi avaliar a influência (in vivo e in vitro) de um extrato de Uncaria tomentosa (unha de gato) na marcação de hemácias e proteínas plasmáticas e celulares com tecnécio-99m (Tc-99m). Para o estudo in vivo, animais foram tratados com um extrato de unha de gato. Para o estudo in vitro, sangue heparinizado foi incubado com o extrato de unha de gato antes da adição de cloreto estanoso (SnCl2) e Tc-99m. Amostras de plasma e células foram separadas e também precipitadas com ácido tricloracético. As frações solúveis e insolúveis foram isoladas. A análise dos resultados do estudo in vivo, indica que não houve alteração significante na captação de Tc-99m pelos constituintes sanguíneos, entretanto, no tratamento in vitro, ocorreu redução significante da marcação de constituintes sanguíneos. Esses efeitos poderiam ser justificados por quelação dos íons estanoso e pertecnetato e bloqueio dos sítios de ligação do Tc-99m

Drug interaction with radiopharmaceuticals: effect on the labeling of red blood cells with technetium-99m and on the bioavailability of radiopharmaceuticals

The evidence that natural and synthetic drugs can affect radiolabeling or bioavailability of radiopharmaceuticals in setting of nuclear medicine clinic is already known. However, this drug interaction with radiopharmaceuticals (DIR) is not completely understood. Several authors have described the effect of drugs on the labeling of blood elements with technetium-99m (99mTc) and on the biodistribution of radiopharmaceuticals. When the DIR is known, if desirable or undesirable, the natural consequence is a correct diagnosis. However, when it is unknown, it is undesirable and the consequences are the possibility of misdiagnosis and/or the repetition of the examination with an increase of radiation dose to the patient. The possible explanation to the appearance of DIR are (a) radiopharmaceutical modification, (b) alteration of the labeling efficiency of the radiopharmaceutical, (c) modification of the target, (d) modification of no target and/or the (e) alteration of the binding of the radiopharmaceutical on the blood proteins. The effect of drugs on the labeling of blood elements with 99mTc might be explained by (i) a direct inhibition (chelating action) of the stannous and pertechnetate ions, (ii) damage induced in the plasma membrane, (iii) competition of the cited ions for the same binding sites, (iv) possible generation of reactive oxygen species that could oxidize the stannous ion and/or (v) direct oxidation of the stannous ion. In conclusion, the development of biological models to study the DIR is highly relevant.<br>A evidência de que drogas naturais ou sintéticas podem afetar a radiomarcação ou a biodisponibilidade de radiofármacos nos procedimentos de medicina nuclear já é bem conhecida. Entretanto, essa interação de droga com radiofármacos (IDR) não está completamente compreendida. Vários autores têm descrito o efeito de drogas na marcação de elementos sanguíneos com tecnécio-99m (99mTc)e na biodistribuição de radiofármacos. Quando a IDR é conhecida, se desejada ou indesejada, a conseqüência natural é um diagnóstico correto. Quando a IDR é desconhecida, ela é indesejada e as conseqüências são a possibilidade de diagnóstico impreciso e/ou a repetição do exame com um aumento de dose de radiação para o paciente. As possíveis explicações para o aparecimento da IDR são (a) modificação do radiofármaco, (b) alteração da eficiência de marcação do radiofármaco, (c) modificação do alvo, (d) modificação do não alvo e/ou (e) alteração da ligação do radiofármaco aos elementos sanguíneos. O efeito de drogas na marcação de elementos sanguíneos com 99mTc poderia ser explicado por (i) uma direta inibição (ação quelante) dos íons estanoso e pertecnetato, (ii) danos na membrana eritrocitária, (iii) competição dos referidos íons pelos mesmos sítios de ligação, (iv) possível geração de espécies reativas de oxigênio e/ou direta oxidação do íon estanoso. Em conclusão, o desenvolvimento de modelos biológicos para o estudo da IDR é altamente relevante