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.

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.

Experimental models using radionuclides for assessment of the effects of natural drugs

The aim of this study was to evaluate the effect of the extracts of Nectandra membranacea (N. membranacea), Ginkgo biloba (EGb) and Passiflora (PEF) on the morphology of red blood cells (RBC), on the biodistribution of sodium pertechnetate (99mTcO4Na), on the morphology of duodenum and on the labeling of blood constituents (BC, IF-P, IF-BC) with technetium-99m (Tc-99m). Morphometry studies also were performed. The results show that EGb promotes alteration of the labeling of BC, IF-P and IF-BC (p<0.05). The N. membranacea extract does not promote significant alteration of the radiolabeling, and PEF extract alters the IF-P labeling. N. membranacea, EGb and PEF extracts were able to alter the RBC morphology (P<0.05). N. membranacea extract and EGb modifies the biodistribution of the 99mTcO4Na, and EGb influences the morphometry of duodenum isolated from rats (P<0.05).

O objetivo deste estudo foi avaliar o efeito de um extrato de Nectandra (N. membranacea), de Ginkgo (EGb) e de Passiflora e. flavicarpa (PEF) na marcação de constituintes sanguíneos (BC, IF-P, IF-BC) com Tc-99m, na morfologia de hemácias (RBC), na biodistribuição do 99mTcO4Na na morfologia do duodeno. Amostras de sangue foram incubadas com os extratos. Tc-99m foi adicionado e as frações do plasma (IF-P) e da célula (IF-BC) foram isoladas. Estudos morfométricos foram realizados. Os resultados mostram que EGb promove alteração na marcação de BC, IF-P e IF-BC. N. membranacea não altera a radiomarcação e PEF altera a marcação de IF-P. O extrato de N. membranacea, EGb e PEF alteraram a morfologia de RBC (p<0.05). Os extratos de N. membranacea e EGb modificam a biodistribuição do 99mTcO4Na, e o EGb influencia a morfometria (p<0.05) do duodeno de ratos.

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.

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.

Effect of Ginkgo biloba on the labeling of blood elements with technetium-99m: in vitro study

Ginkgo biloba is the phytoterapic most used in popular medicine in the treatment of cerebral senescence. Red blood cells (RBC) labeled with technetium-99m (Tc-99m) is used for several evaluations in nuclear medicine. This labeling depends on a reducing agent, usually the stannous ion. Any drug, which alters the labeling of the tracer, could be expected to modify the disposition of the radiopharmaceutical. We have evaluated the influence of the Ginkgo biloba extract on the labeling of RBC and plasma proteins with Tc-99m. Blood was withdrawn and incubated with Ginkgo biloba extract (0; 0.004; 0.04; 0.4; 4; 20 and 40 mg/ml). Stannous chloride (1.2 ml/ml) was added and, then, Tc-99m was added. Plasma (P) and blood cells (RBC) were isolated, also precipitated with trichloroacetic acid and soluble (SF) and insoluble fractions (IF) separated. The analysis of the results shows that there is a decrease in the radioactivity (from 97.7 ± 0.7 to 49.5 ± 3.9 percent) in RBC with the drug (4 mg/ml). In the labeling process of RBC with Tc-99m, the stannous and pertechnetate ions pass though the membrane, so, we suggest that the Ginkgo biloba effect can be explained by (i) an inhibition of the transport of these ions, (ii) damage in membrane, (iii) competition with the cited ions for the same binding sites, or (iv) possible generation of reactive oxygen species that could oxidize the stannous ion.