RESUMO
Taraxacum officinale leaves were collected at two and 5 months of growth, for antiviral activity against flavivirus, using the 17D vaccine strain of yellow fever virus as a model. Using spectroscopy technique, a total of twelve (12) compounds were identified in the chloroform (C) and hexane (H) extracts of two and five months (2M and 5M) of recollection., The antiviral activity against the yellow fever 17D virus was evaluated with the plaque assay and the concentrations used (50 - 1,5 ug/mL) were no cytotoxic to Vero cells as determined using the MTT(3-(4,5-Dimetiltiazol-2yl)-2,4-difenilbromuro de tetrazolium) assay. The phytochemical composition of leaves growing for 5 months is different and more complex than leaves growing for 2 months. From the four extracts, only C5M inhibited the viral replication in a dose depend manner, with 100 percent viral inhibition at 50 ug/mL (p=0,0124) and the effective doses 50 (ED50: 10,2 +/- 8,7 ug/mL), meanwhile, ED50 of C2M extract was 93,5 +/- 23,5 ug/mL, thus, the extract C5M is 8 times more effective than extract C2M. The identified compounds in extract C5M were: Psi taraxasteryl acetate, cafeic acid, taraxasteryl acetate, taraxerol, taraxerilo acetate and Psi-taraxasterol. One of these compounds or the combinations of them is responsible for the reported high antiviral activity.
Las hojas de Taraxacum officinale fueron colectadas a dos y cinco meses de crecimiento, para determinar actividad antiviral contraflavivirus, utilizando como modelo el virus de fiebre amarilla cepa vacunal 17D. Se identificaron por métodos espectroscópicos, un total de doce (12) compuestos provenientes de los extractos de hexano (H) y cloroformo (C) a dos y cinco meses (2M y 5M) de recolección La actividad antiviral se determinó mediante un ensayo de placa y las concentraciones de extractos utilizadas (50-1,5 ug/mL) fueron no citotóxica en células Vero, determinadas por el método colorimétrico del MTT (3-(4,5-Dimetiltiazol-2yl)-2,4-difenilbromuro de tetrazolio). La composición fitoquímica de los extractos de 5 meses es distinta y más compleja que la de dos meses de crecimiento. De los cuatro extractos sólo el C5M inhibió la replicación del virus en una manera dosis dependiente, con una inhibición del 100 por ciento a 50 ug/mL (p=0,0124) y una dosis efectiva 50 (DE50) de 10,2 +/- 8,7 ug/mL, mientras que el DE50 del extracto C2M es de 93,5 +/- 23,5 ug/mL, lo que hace al extracto clorofórmico de 5 meses aproximadamente 8 veces más efectivo que el C2M. Los compuestos presentes en el extracto C5M son Psi taraxasterilo, ácido cafeíco, acetato de taraxasterilo, taraxerol, acetato de taraxerilo y Psi-taraxasterol. Uno o más de estos compuestos son responsables de alta actividad antiviral reportada.
Assuntos
Antivirais/farmacologia , Extratos Vegetais/farmacologia , Flavivirus , Folhas de Planta/química , Taraxacum/química , Taraxacum/farmacologia , Febre AmarelaRESUMO
From the n-butanol extract of the aerial parts of Exellodendron coriaceum (Benth.) Prance the flavonoids quercetin-3-O-beta-D-galactopyranoside (1), quercetin-3-O-alpha-L-arabinopyranoside (2), quercetin-3-O-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-rhamnopyranoside (3), and quercetin-3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-galactopyranoside (4) were isolated. Additionally from this extract three flavonoids were isolated and partially characterized as quercetin glycosides. All these compounds were tested for their hypoglycemic activity using the glucose-6-phosphatase microsomal hepatic system. The flavonoids inhibited the activity of the enzyme when intact microsomes were used, the highest percentage of inhibition being 65%. To the best of our knowledge, this is the first report of chemical and biological activity of E. coriaceum.
Assuntos
Inibidores Enzimáticos/química , Flavonoides/química , Glucose-6-Fosfatase/antagonistas & inibidores , Hipoglicemiantes/química , Magnoliopsida/química , Animais , Inibidores Enzimáticos/isolamento & purificação , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Frutas/química , Hipoglicemiantes/isolamento & purificação , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Folhas de Planta/química , Quercetina/química , Quercetina/isolamento & purificação , Quercetina/farmacologia , Ratos , Espectrometria de Massas por Ionização por Electrospray , Relação Estrutura-AtividadeRESUMO
Thirteen new triterpenoid saponins (1-13) were isolated from the aerial parts of Campsiandra guayanensis. Their structures were elucidated by 1D and 2D NMR experiments including 1D-TOCSY, DQF-COSY, ROESY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis. The aglycon moieties of 1-10 were assigned as oleanane derivatives and those of 11-13 as lupane derivatives.
Assuntos
Caesalpinia/química , Plantas Medicinais/química , Saponinas/isolamento & purificação , Triterpenos/isolamento & purificação , Sequência de Carboidratos , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Saponinas/química , Espectrometria de Massas por Ionização por Electrospray , Triterpenos/química , VenezuelaRESUMO
From the methanol extract of Bauhinia megalandra fresh leaves, eight flavonoids were isolated and evaluated by rat liver microsomal glucose-6-phosphatase (G-6-Pase) bioassay, which might be a useful methodology for screening antihyperglycaemic substances. All the flavonoids assayed showed an inhibitory effect on the intact microsomal G-6-Pase: quercetin and kaempferol exhibited the lowest effect; astilbin, quercetin 3-O-alpha-rhamnoside, kaempferol 3-O-alpha-rhamnoside and quercetin 3-O-alpha-arabinoside an intermediate effect. The highest inhibitory activity was shown by quercetin 3-O-alpha-(2''-galloyl)rhamnoside and kaempferol 3-O-alpha-(2''galloyl)rhamnoside. None of the flavonoids mentioned above showed an inhibitory effect on the disrupted microsomal G-6-Pase. Quercetin 3-O-alpha-(2''-galloyl)rhamnoside and kaempferol 3-O-alpha-(2''-galloyl)rhamnoside exhibited the lowest IC50 of all the flavonoids assayed. Also, the phlorizin IC50 is reported.
Assuntos
Bauhinia , Inibidores Enzimáticos/farmacologia , Glucose-6-Fosfatase/antagonistas & inibidores , Hipoglicemiantes/farmacologia , Fitoterapia , Extratos Vegetais/farmacologia , Animais , Diabetes Mellitus/prevenção & controle , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/química , Inibidores Enzimáticos/uso terapêutico , Flavonoides/administração & dosagem , Flavonoides/farmacologia , Flavonoides/uso terapêutico , Hipoglicemiantes/administração & dosagem , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , Concentração Inibidora 50 , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Folhas de Planta , RatosRESUMO
A new kaurane diterpene dimer, 15-oxozoapatlin-13alpha-yl-10'alpha,16'alpha-dihydroxy-9'alpha-methyl-20'-nor-kauran-19'-oic acid gamma-lactone-17'-oate (1), together with the known 13-hydroxy-15-oxozoapatlin (2), 10alpha,13alpha,16alpha,17-tetrahydroxy-9alpha-methyl-15-oxo-20-nor-kauran-19-oic acid gamma-lactone (3), 2alpha,10alpha,13alpha,16alpha,17-pentahydroxy-9alpha-methyl-15-oxo-20-nor-kauran-19-oic acid (19,10)-lactone (4), 3alpha,10alpha,13alpha,16alpha,17-pentahydroxy-9alpha-methyl-15-oxo-20-nor-kauran-19-oic acid gamma-lactone (5), and 1beta,16alpha,17-trihydroxy-ent-kaurane (6) were isolated from the leaves of Parinari campestris and identified on the basis of detailed spectral analysis, including 2D NMR spectrometry and ESI-MS.
Assuntos
Chrysobalanaceae/química , Diterpenos do Tipo Caurano/química , Diterpenos do Tipo Caurano/isolamento & purificação , Lactonas/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Folhas de Planta/químicaRESUMO
In intact microsomes, quercetin 3-O-alpha-(2''-galloyl)rhamnoside (QGR) inhibits glucose-6-phosphatase (G-6-Pase) in a concentration-dependent manner. QGR increased the G-6-Pase K(m) for glucose-6-phosphate without change in the V(max). The flavonol did not change the kinetic parameters of disrupted microsomal G-6-Pase or intact or disrupted microsomal G-6-Pase pyrophosphatase (PPase) activity. This result allowed the conclusion that QGR competitively inhibits the glucose-6-phosphate (G-6-P) transporter (T1) without affecting the catalytic subunit or the phosphate/pyrophosphate transporter (T2) of the G-6-Pase system.QGR strongly inhibits the neoglucogenic capacity of rat liver slices incubated in a Krebs-Ringer bicarbonate buffer, supplemented with lactate and oleate saturated albumin. The QGR G-6-Pase inhibition might explain the decrease in the liver slice neoglucogenic capacity and, in turn, could reduce glucose levels in diabetic patients.
Assuntos
Bauhinia , Inibidores Enzimáticos/farmacologia , Gluconeogênese/efeitos dos fármacos , Glucose-6-Fosfatase/efeitos dos fármacos , Fitoterapia , Extratos Vegetais/farmacologia , Animais , Antiporters/efeitos dos fármacos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/uso terapêutico , Glucose-6-Fosfatase/antagonistas & inibidores , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Proteínas de Transporte de Monossacarídeos/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/uso terapêutico , Folhas de Planta , Quercetina/administração & dosagem , Quercetina/farmacologia , Quercetina/uso terapêutico , Ratos , Ratos Sprague-DawleyRESUMO
Twenty-three kaurane-type diterpenes 1 - 23, including twenty new natural products 1 - 20, have been isolated from the leaves of Parinari sprucei and their structures elucidated by spectroscopic and chemical analysis. The isolated compounds were tested for their cytotoxic activity towards a panel of cancer cell lines. Compounds 9 and 10 showed activity against all cell lines with ED (50) values in the range of 10 - 20 microg/mL. The previously known 13-hydroxy-15-oxozoapatlin 21 was evaluated in an in vivo hollow fiber test, and found to be active with KB and LNCaP cells at the concentrations used.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Fitoterapia , Picea , Extratos Vegetais/farmacologia , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/uso terapêutico , Linhagem Celular Tumoral/efeitos dos fármacos , Diterpenos do Tipo Caurano/administração & dosagem , Diterpenos do Tipo Caurano/química , Diterpenos do Tipo Caurano/farmacologia , Diterpenos do Tipo Caurano/uso terapêutico , Humanos , Espectroscopia de Ressonância Magnética , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Folhas de PlantaRESUMO
Two new myricetin glycosides, myricetin 7-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside (1) and myricetin 7-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-glucopyranoside (2), together with the known compounds quercetin 3-O-beta-D-glucopyranoside (3), quercetin 3-O-alpha-L-rhamnopyranoside (4), quercetin 3-O-beta-D-galactopyranoside (5), methyl gallate (6), isovanillin (7), 4-hydroxymethylbenzoate (8), 3,4-dihydroxymethylbenzoate (9), and caffeoyl aldehyde (10) were isolated from the leaves of Tachigalia paniculata. The structures of these compounds were determined by spectroscopic methods. Their antioxidant activity was determined by measuring free-radical scavenging effects using three different assays, namely, the Trolox Equivalent Antioxidant Capacity (TEAC) assay, the coupled oxidation of beta-carotene and linoleic acid (autoxidation assay), and the inhibition of xanthine oxidase activity. Compounds 1, 2, and 6 showed activity in the TEAC test, compounds 5-7 and 10 were moderately active in the autoxidation assay, while compounds 1 and 2 were the most potent of the isolates in the xanthine oxidase test.
Assuntos
Antioxidantes/isolamento & purificação , Fabaceae/química , Flavonoides/isolamento & purificação , Sequestradores de Radicais Livres/isolamento & purificação , Glicosídeos/isolamento & purificação , Plantas Medicinais/química , Algoritmos , Antioxidantes/química , Antioxidantes/farmacologia , Cromatografia Líquida de Alta Pressão , Flavonoides/química , Flavonoides/farmacologia , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/farmacologia , Glicosídeos/química , Glicosídeos/farmacologia , Concentração Inibidora 50 , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Oxirredução , Folhas de Planta/química , Estereoisomerismo , Venezuela , Xantina Oxidase/metabolismo , beta Caroteno/metabolismoRESUMO
In our screening program for antioxidants with DPPH radical scavenging activity we tested several flavonoids isolated from the leaves of Licania licaniaeflora (Chrysobalanaceae family) and identified by spectroscopic evidence, particularly with 1H and 13C NMR. All the isolated compounds exhibited DPPH radical scavenging activity: quercetin derivatives showed the strongest action, while the flavanone 8-hydroxy-naringenin and kaempferol 3-O-alpha-rhamnoside had the lowest.