RESUMO

Nineteen plants from the Republic of Panama were selected by their traditional uses in the treatment of hypertension, cardiovascular, mental and feeding disorders and 149 extracts were screened using radioligand-receptor-binding assays. The methanol:dicloromethane extracts of the bark and leaves of Anacardium occidentale L., the leaves of Begonia urophylla Hook., the roots of Bocconia frutescens L., the stems and leaves of Cecropia cf.obtusifolia Bertol., the branches of Clusia coclensis Standl., the bark of Cochlospermum vitifolium (Willd.)Spreng., the roots of Dimerocostus strobilaceus Kuntze, the bark of Guazuma ulmifolia Lam., the leaves of Persea americana Mill. and the branches of Witheringia solanaceae L'Her. inhibited the [3H]-AT II binding (angiotensin II AT1 receptor) more than 50%. Only extracts of the roots of Dimerocostus strobilaceus Kuntze and the stems of Psychotria elata (Sw.) Hammel were potent inhibitors of the [3H] NPY binding (neuropeptide Y Y1 receptor) more than 50% and the ethanolic extracts of the leaves of Cecropia cf. obtusifolia Bertol., the leaves of Hedyosmum bonplandianum H.B.K., the roots of Bocconia frutescens L., the stem of Cecropia cf. obtusifolia Bertol. and the branches of Psychotria elata (Sw.) Hammel showed high inhibition of the [3H] BQ-123 binding (endothelin-1 ET(A) receptor) in a preliminary screening. These results promote the further investigation of these plants using the same assays.

Assuntos

Peptídeos Cíclicos/efeitos dos fármacos , Extratos Vegetais/farmacologia , Plantas Medicinais , Receptores de Angiotensina/efeitos dos fármacos , Receptores de Neuropeptídeo Y/efeitos dos fármacos , Humanos , Medicina Tradicional , Panamá , Ensaio Radioligante , Receptor Tipo 1 de Angiotensina

RESUMO

Several plants collected through different approaches were screened on distinct receptors using ligand-binding studies as bioassay. Extracts of Microtea debilis showed high activity on adenosine A1 receptors. Bioassay-guided fractionation using ligand-binding studies resulted in the isolation of an adenosine A1 active ligand, cirsimarin (cirsimaritin 4'-O-glucoside). GTP did not influence the radioligand inhibition curve of cirsimarin, indicating that this compound is acting as an antagonist at the adenosine-A1 receptors. The use of this plant against "proteinuria" in traditional medicine in Suriname (South America) may be explained by the adenosine A1 antagonistic action of cirsimarin. A series of flavonoids was tested in the same assay, but they were less active. No structure-activity relationship could be observed.

Assuntos

Flavonas , Flavonoides/isolamento & purificação , Glicosídeos/isolamento & purificação , Receptores Purinérgicos P1/efeitos dos fármacos , Animais , Flavonoides/química , Flavonoides/farmacologia , Glicosídeos/química , Glicosídeos/farmacologia , Técnicas In Vitro , Ligantes , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Membranas/efeitos dos fármacos , Membranas/metabolismo , Extratos Vegetais/química , Prosencéfalo/efeitos dos fármacos , Prosencéfalo/metabolismo , Antagonistas de Receptores Purinérgicos P1 , Ensaio Radioligante , Ratos , Espectrofotometria Ultravioleta , Suriname , Xantinas

RESUMO

Ligand-binding-studies on twelve different receptors were used for screening extracts from plants from Suriname (South-America). The results on 5-HT(1A), A(1) and NMDA receptors promote further investigation of Microtea debilis, Hibiscus bifurcatus, Irlbarchia purpurascens, Miconia ciliata and Mimosa myriadena.

RESUMO

Plants from Suriname (South-America) and several Annona species, including A. muricata, A. ckerimolia, A. montana and A. glabra were screened for 5-HT(1A) receptor binding activity by ligand-binding-studies (LBS). Crude extracts of all Annona species and from Hibiscus bifurcatus, Irlbarchia purpurascens and Scoparia dulcis showed high activity. The isoquinoline alkaloids asimilobine (1), nornuciferine (2), and annonaine (3) were isolated as the active principles from the fruit of Annona muricata. These results may partially explain the use of Hibiscus bifurcatus and Annona muricata in traditional medicine in Suriname.