RESUMO
Amphibian skin has been the source of a wide variety of biologically active substances, but less than one-third of the known genera of amphibians have been probed for such active substances. Skins of 21 genera of anurans from Thailand have now been investigated for noxious secretions, toxic substances, and alkaloids. Four genera of bufonid toads (Bufo, Ansonia, Leptophryne, Pedostipes) were toxic due to the presence of bufadienolides or bufadienolide-like compounds. Two species of ranid frogs (Rana raniceps, Rana signata) were toxic, perhaps due to the presence of toxic peptide(s). Two species of rhacophorid frogs (Polypedates) were slightly noxious/toxic. One species of microhylid frog (Kaloula pulchra) was noxious. Trace amounts of pumiliotoxin alkaloids were detected in a ranid frog (Limnonectes kuhli). A further 18 species did not exhibit noxious or toxic properties to a significant extent.
Assuntos
Anuros/metabolismo , Pele/química , Toxinas Biológicas/isolamento & purificação , Alcaloides/isolamento & purificação , Alcaloides/toxicidade , Aminas/isolamento & purificação , Aminas/toxicidade , Animais , Bufanolídeos/isolamento & purificação , Bufanolídeos/toxicidade , Masculino , Camundongos , Estrutura Molecular , Paladar , Tailândia , Toxinas Biológicas/toxicidadeRESUMO
A limonoid, clausenolide-1-ethyl ether (1) and two coumarins, dentatin (2) and nor-dentatin (3), were isolated from Clausena excavata. Limonoid 1 was obtained from the crude ethanol extract of the rhizomes and the roots but had not previously been isolated from C. excavata and exhibited HIV-1 inhibitory activity. Coumarins 2 and 3, with their structures related to an anti-HIV-1 substance, (+)-calanolide A (4), were obtained from the crude chloroform extract of the rhizomes. Both induced toxicity to cells used in a syncytium assay for anti-HIV-1 activity. These compounds, 1-3, did not show any cytotoxic effect against KB and BC-1 cell lines (IC(50) value > 20 microgram/mL).
Assuntos
Fármacos Anti-HIV/farmacologia , Antineoplásicos Fitogênicos/farmacologia , HIV-1/efeitos dos fármacos , Limoninas/farmacologia , Fitoterapia , Extratos Vegetais/farmacologia , Rutaceae , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/uso terapêutico , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/uso terapêutico , Linhagem Celular Tumoral/efeitos dos fármacos , Células Cultivadas , Feminino , Humanos , Limoninas/administração & dosagem , Limoninas/uso terapêutico , Testes de Sensibilidade Microbiana , Extratos Vegetais/administração & dosagem , Extratos Vegetais/uso terapêuticoRESUMO
Four known coumarins, dentatin (1), nor-dentatin (2), clausenidin (3) and xanthoxyletin (5), and six known carbazole derivatives, 3-formylcarbazole (6), mukonal (7), 3-methoxycarbonylcarbazole (8), murrayanine (9), 2-hydroxy-3-formyl-7-methoxycarbazole (10) and clauszoline J (11) were isolated from Clausena excavata. Compounds 1 and 6 were first isolated from the crude chloroform extract of the rhizomes. Compounds 1, 2, 3, 6, 7, 8, 10 and 11 showed antimycobacterial activity at a minimum inhibitory concentration (MIC) of 50, 100, 200, 100, 200, 50, 100 and 100 microg/mL, respectively. O-Methylated clausenidin ( 4), prepared from 3, exhibited antimycobacterial activity at MIC 50 microg/mL. Compounds 6, 7, 8 and 10 showed antifungal activity with IC 50 values of 13.6, 29.3, 9.5 and 2.8 microg/mL, respectively. All compounds demonstrated no cytotoxicity against KB and BC-1 cell lines.