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

Moreno, Silvana Ramos Farias; Feliciano, Gláucio Diré; Freitas, Rosimeire Souza; Farah, Miguel Benito; Laurentino-Filho, Guilherme Lima; Rocha, Emely Kazan; Jales, Roberto Levi Cavalcanti; Bernardo Filho, Mario

doi:10.1590/S0102-695X2002000300030

Abstract

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 Blood was withdrawn and incubated with Ginkgo biloba extract (0; 0.004; 0.04; 0.4; 4; 20 and 40 mg/ml).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%) 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.

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

Silvana Ramos Farias Moreno^{I, II}; Gláucio Diré Feliciano^II; Rosimeire Souza Freitas^II; Miguel Benito Farah^I; Guilherme Lima Laurentino-Filho^II; Emely Kazan Rocha^III; Roberto Levi Cavalcanti Jales^IV; Mario Bernardo Filho^II,^*

^IUniversidade Federal Fluminense, Departamento de Patologia; Niterói, RJ

^IIUniversidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamento de Biofísica e Biometria, 20551-030, Rio de Janeiro, RJ

^IIIUniversidade do Estado do Rio de Janeiro, Instituto de Biologia Roberto Alcantara Gomes, Departamento Biologia Celular e Genética, Rio de Janeiro, RJ

^IVUniversidade Federal do Rio Grande do Norte, Faculdade de Farmácia, Natal, RN, Brasil

ABSTRACT

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%) 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.

Full text available only in PDF format.

Texto completo disponível apenas em PDF.

References

1 Yucheng N, Baolu Z, Jingwu H, Wenjuan X. Preventive effect of Ginkgo biloba extract on apoptosis in rat cerebellar neuronal cells induced by hydroxyl radicals. Neuroscience Letters 1996; 214: 115-18
2 Diamond BJ, Shiflet SC, Fewel N, Matheis RJ; Noskin O, Richards JA. Ginkgo biloba extract: mechanisms and clinical indications. Archives Physical Medicine and Rehabilitation 2000; 81:668-78
3 Galluzzi S, Zanetti G, Binetti G, Trabucchi M, Frisoni GB. Coma in patient with Alzheimer' s disease takinglow doses the Ginkgo biloba Journal Neurology Neurosurgery Psychiatry 2000; 68: 679-80
4 Early PJ, Sodee DB. Principles and Practice of Nuclear Medicine, Mosby YearBook, 1995; 887p
5 Harbert JC, Eckelman, WC, Neumann, RD. Nuclear Medicine Diagnosis and Therapy, Thieme Medical Publishers, Inc., New York, 1996
6 Bernardo-Filho M, Gutfilen B, Maciel OS. Effect of different anticoagulants on the labeling of red blood cells and plasma proteins with technetium-99m. Nuclear Medicine Communications 1994; 15: 730-34
7 Sampson CB. Complications and difficulties in radiolabeling blood cells: A review. Nuclear Medicine Comunications 1996; 17: 648-58
8 Billinghurst MW, Jette D. In vitro kinetics of red blood cell labeling with 99mTc in association with stannous pyrophosphate. Journal of Radioanalitical Chemistry 1980; 59: 579-84
9 Vidal MV, Gutfilen B, Fonseca LMB, Bernardo-Filho M. Influence of tobacco on labeling of red blood cells and plasma proteins with technetium-99m. Journal of Experimental and Clinical Cancer Research 1998; 17: 1-6
10 Oliveira, JF , Braga, ACC, Ávila AS, Fonseca LMB, Gutfilen, B Bernardo-Filho, M. Effect of Thuya occidentalis on the labeling of red blood cells and plasma proteins with technetium-99m. The Yale Journal of Biology and Medicine 1997; 69: 489-94