RESUMO
In traditional medicine Gossypium barbadense L. is used against hypertension. Looking for a scientific basis for this use, the blood-pressure-lowering effect of the decoction of the leaves was confirmed. Fraction II (frII) of the crude extract of G. barbadense showed a dose-dependent hypotensive effect in anaesthetized rats. In hexamethonium-treated rats, the blood-pressure-lowering effect of frII was almost abolished. A small decrease of the blood-pressure-lowering effect was followed by an increase in the blood pressure. Phentolamine antagonized the increase in blood pressure in hexamethoniumtreated rats. High doses of atropine (4 mg/rat) suppressed both depressor and heart effects. In-vitro experiments revealed that atropine did not antagonize the contraction of the ileum of the rat. Tripelennamine in a concentration of 100 microg could not influence the contraction either, whereas 300 microg did. In the guinea-pig ileum 10 microg tripelennamine did not reduce the contraction significantly. In the mechanism of action of frII, acetylcholine receptors could be involved, but not histaminergic or adrenergic receptors. Although it is still not known which compound(s) in G. barbadense is (are) the active substance(s), the results obtained may explain the use of this plant in traditional medicine in Suriname.
Assuntos
Gossypium , Hipotensão/induzido quimicamente , Plantas Medicinais , Animais , Atropina/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Cobaias , Hexametônio/farmacologia , Íleo/efeitos dos fármacos , Injeções Intraperitoneais , Medicina Tradicional , Contração Muscular , Fenoxibenzamina/administração & dosagem , Extratos Vegetais/antagonistas & inibidores , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Folhas de Planta/química , Propranolol/administração & dosagem , Ratos , Ratos Wistar , Suriname , ÁguaRESUMO
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 AngiotensinaRESUMO
A series of dimeric procyanidins (1-9) and some related polyphenols (10-15) were chosen as model compounds in a comparative investigation for various biological activities in order to obtain structure-activity relationships. Antiviral [herpes simplex virus (HSV) and human immunodeficiency virus (HIV)], antibacterial, superoxide radical-scavenging, and complement-modulating properties were assessed. In general, more pronounced activities were seen with epicatechin-containing dimers for anti-HSV, anti-HIV, and radical-scavenging effects, while the presence of ortho-trihydroxyl groups in the B-ring was important in compounds exhibiting anti-HSV and radical-scavenging effects and complement classical pathway inhibition. Double interflavan linkages gave rise to interesting antiviral effects (HSV and HIV) and complement inhibition. The influence of the degree of polymerization or the type of interflavan linkage (4-->6 or 4-->8) differed in the different biological systems evaluated. Only minor or moderate antibacterial effects were observed for the compounds under investigation.
Assuntos
Antocianinas/farmacologia , Anti-Infecciosos/farmacologia , Antivirais/farmacologia , Proteínas Inativadoras do Complemento/farmacologia , Flavonoides , Sequestradores de Radicais Livres/farmacologia , Fenóis/farmacologia , Plantas Medicinais/química , Polímeros/farmacologia , Antocianinas/química , Antocianinas/isolamento & purificação , Antibacterianos , Fármacos Anti-HIV/farmacologia , Bactérias/efeitos dos fármacos , Euphorbiaceae/química , Hemólise/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Peru , Simplexvirus/efeitos dos fármacosRESUMO
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.