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1.
Planta Med ; 86(1): 78-84, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31652477

RESUMEN

Common chronic conditions such as metabolic syndrome and diabetes are increasingly associated to metabolic and cardiovascular complications. Although Phyllanthus tenellus leaves have been used in decoctions as a popular remedy to control blood glucose levels and hypertension, its use needs a scientific basis. This study was therefore undertaken to report a phytochemical analysis of P. tenellus leaves and to test if the main active compound has potential to simultaneously tackle several pathophysiological features of metabolic syndrome and diabetes-related metabolic and vascular disorders such as hyperglycaemia, increased platelet activation, and endothelial dysfunction. We performed a partition of the methanolic extract of P. tenellus leaves among different organic solvents followed by chromatographic separation guided by the rat liver microsomal glucose-6-phosphatase assay. Two known tannins were identified by spectroscopic methods as pinocembrin-7-O-[3″-O-galloyl-4″,6″-(S)-hexahydroxydiphenoyl]-α-D-glucose, named P7OG by us, and gemin D. The structural determination of the isolated compounds was based on spectral data. The ability of the main active component, P7OG, to inhibit human platelet aggregation and to modify vascular reactivity of rat aortic rings incubated with high glucose (D-glucose 55 mM) was then evaluated. P7OG was further able to inhibit platelet aggregation induced by adenosine 5'-diphosphate and collagen, showed vasorelaxant effects in arteries precontracted with phenylephrine, and reverted the endothelium-dependent impairment effect of high glucose in rat aortic rings. In conclusion, one tannin isolated from P. tenellus showed promising metabolic, antiaggregant, and vascular effects, which suggests the potential beneficial use of P. tenellus to tackle complex cardiometabolic diseases.


Asunto(s)
Sistema Cardiovascular/efectos de los fármacos , Metabolismo/efectos de los fármacos , Phyllanthus/química , Extractos Vegetales/farmacología , Adulto , Animales , Cardiomiopatías Diabéticas/tratamiento farmacológico , Humanos , Masculino , Síndrome Metabólico/tratamiento farmacológico , Estructura Molecular , Extractos Vegetales/química , Extractos Vegetales/uso terapéutico , Hojas de la Planta/química , Agregación Plaquetaria/efectos de los fármacos , Ratas , Ratas Sprague-Dawley
2.
Arch. venez. farmacol. ter ; 28(1): 40-42, ene. 2009. ilus, tab
Artículo en Español | LILACS | ID: lil-630354

RESUMEN

En la actualidad muchas investigaciones se han volcado al estudio de la actividad biológica de varias plantas que se considera, en el saber de los pueblos, puedan aliviar los síntomas en pacientes con diabetes, tal es el caso de Bauhinia megalandra. El estudio fitoquímico de las hojas de dicha planta se realizó guiado por bioensayos, evaluando el efecto de cada fracción obtenida sobre la absorción intestinal de glucosa con la finalidad de encontrar aquella que presente el mayor efecto inhibitorio sobre dicha actividad biológica, utilizando para su medición segmentos de intestino de rata aislados in situ. Luego de una serie de extracciones secuenciales con diferentes solventes orgánicos y fraccionamiento por cromatografía de columna en silica gel 60, se logró aislar y caracterizar por métodos espectroscópicos una fracción altamente enriquecida con el flavonoide apigenina glucosilada en el carbono ocho. Dicha fracción fue capaz de inhibir la absorción intestinal de glucosa en un 47,34% con respecto al control, y de generar un efecto aditivo cuando se ensayo junto a la floricina


At present, it has been an increase in the research of the biological activity of plants used by the traditional medicine for the empirical treatment of the diabetes mellitus, such as Bauhinia megalandra. The phytochemical study of the leaves of these plants was done guided by bioassay, evaluating the effect of each fraction on the glucose intestinal absorption, using in situ rat intestinal segments. After a sequential series of extractions with organic solvents and fractionation by column chromatographic on silica gel 60, we isolated a fraction characterized by spectroscopic method to be highly enriched in the flavonoid apigenin glicolisated in the carbon eight. This fraction was able to inhibit in a 47,34% the intestinal glucose absorption compared to control, and showed an additive effect when used simultaneously with phloricin


Asunto(s)
Glucosa , Plantas Medicinales , Farmacología
3.
Rev. bras. farmacogn ; 18(3): 331-338, jul.-set. 2008. tab
Artículo en Inglés | LILACS | ID: lil-496105

RESUMEN

Os extratos aquoso e etanólico derivados de doze espécies coletadas na Amazônia venezuelana foram testados quanto à atividade antioxidante utilizando um radical DPPH e o efeito inibitório sobre a hidrólise de glicose-6-fosfato nos microssomas intactos e perturbados. Sem exceção, todos os extratos inibiram, em maior ou menor grau, a atividade enzimática microssomal de G-6-Pase, resultando em maior inibição nos microssomas intactos do que nos perturbados. Efeitos marcantes foram observados para os extratos aquoso e etanólico de: Tontelea ovalifolia, Gustavia pulchra, Phthirusa verruculosa, Phthirusa castillana, Psittacanthus acimarius, Tetrapterys styloptyera e Vismia japurensis. Os extratos etanólicos foram seqüestradores do radical DPPH mais eficazes do que os correspondentes extratos aquosos em todos os casos. O extrato etanólico de Endlicheria anomala e o extrato aquoso de Phthirusa verruculosa exibiram as melhores CI50 com 100 e 250.0 ppm, respectivamente. Os valores de Kobs calculados para os extratos alcoólicos foram mais baixos do que os dos extratos aquosos das mesmas espécies, exceto Psittacanthus acimarius. Estes resultados poderiam estar relacionados a diferentes concentrações, ou mais provavelmente a diferentes composições de princípios ativos em ambos extratos.


The aqueous and ethanol extracts derived from twelve plant species collected in the Venezuelan Amazon have been tested for antioxidant activity using a DPPH radical and inhibitory effect on the hydrolysis of glucose-6-phosphate in intact and disrupted microsomes. Without exception, all the extracts inhibited, to a greater or lesser degree, microsomal G-6-Pase enzymatic activity, resulting in greater inhibition on intact microsomes than on disrupted ones. Marked effects were observed for aqueous and ethanol extracts of: Tontelea ovalifolia, Gustavia pulchra, Phthirusa verruculosa, Phthirusa castillana, Psittacanthus acimarius, Tetrapterys styloptyera and Vismia japurensis. Ethanol extracts were more effective DPPH radical scavengers than the corresponding aqueous extracts in all the cases. The ethanol extract of Endlicheria anomala and the aqueous extract of Phthirusa verruculosa, showed the best IC50 with 100 and 250.0 ppm, respectively. The Kobs calculated for the alcoholic extracts were lower than those of the aqueous extracts for the same species, except Psittacanthus acimarius. These results could be related to different concentrations, or more likely different compositions of active principles in both extracts.

4.
Arch. venez. farmacol. ter ; 27(2): 129-131, 2008. graf
Artículo en Español | LILACS | ID: lil-517104

RESUMEN

El extracto acuoso de las hojas de Bauhinia megalandra ha sido muy empleado en Venezuela en el tratamiento empírico de la diabetes mellitus. En el presente trabajo se estudió el efecto del extracto acuoso de B. megalandra sobre la glucogenolísis hepática estimulada por adrenalina o dibutiril AMPc. La administración oral del extracto de la planta, a ratas alimentadas, disminuyó de una manera estadísticamente significativa el incremento de la glicemia promovido por la adrenalina. De igual manera, rebanadas de hígado de ratas alimentadas incubadas en presencia del extracto de B. megalandra produjeron menos glucosa en respuesta a la adrenalina o al dibutiril AMPc que los controles. Estos resultados indican una disminución de la glucogenolísis hepática por efecto del extracto acuoso de hojas de B. megalandra, probablemente por inhibición de la enzima glucosa-6-fosfatasa.


Asunto(s)
Animales , Ratas , Bucladesina/administración & dosificación , Bucladesina/uso terapéutico , Diabetes Mellitus , Epinefrina/efectos adversos , /efectos adversos
5.
Phytother Res ; 19(10): 859-63, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16261515

RESUMEN

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.


Asunto(s)
Bauhinia , Inhibidores Enzimáticos/farmacología , Glucosa-6-Fosfatasa/antagonistas & inhibidores , Hipoglucemiantes/farmacología , Fitoterapia , Extractos Vegetales/farmacología , Animales , Diabetes Mellitus/prevención & control , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/uso terapéutico , Flavonoides/administración & dosificación , Flavonoides/farmacología , Flavonoides/uso terapéutico , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/química , Hipoglucemiantes/uso terapéutico , Concentración 50 Inhibidora , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/enzimología , Extractos Vegetales/administración & dosificación , Extractos Vegetales/química , Extractos Vegetales/uso terapéutico , Hojas de la Planta , Ratas
6.
Phytother Res ; 19(7): 624-7, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16161025

RESUMEN

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.


Asunto(s)
Bauhinia , Inhibidores Enzimáticos/farmacología , Gluconeogénesis/efectos de los fármacos , Glucosa-6-Fosfatasa/efectos de los fármacos , Fitoterapia , Extractos Vegetales/farmacología , Animales , Antiportadores/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/administración & dosificación , Inhibidores Enzimáticos/uso terapéutico , Glucosa-6-Fosfatasa/antagonistas & inhibidores , Masculino , Microsomas Hepáticos/efectos de los fármacos , Microsomas Hepáticos/enzimología , Proteínas de Transporte de Monosacáridos/efectos de los fármacos , Extractos Vegetales/administración & dosificación , Extractos Vegetales/uso terapéutico , Hojas de la Planta , Quercetina/administración & dosificación , Quercetina/farmacología , Quercetina/uso terapéutico , Ratas , Ratas Sprague-Dawley
7.
Acta cient. venez ; 49(3): 179-86, 1998. ilus, tab
Artículo en Inglés | LILACS | ID: lil-225379

RESUMEN

The effect of the administration of seven doses of the hepatocarcinogen thioacetamide on the chemical composition of rat liver nuclear envelope subfractions: associated chromatin, nuclear membranes and pore complex-lamina fraction, is analyzed. No alteration in DNA, RNA or phospholipid content is observed after the hepatocarcinogen treatment. Electrophoretic studies of each subfraction from thioacetamide treated rats show differences in the relative proportions of some polypeptides when compared with the controls. Examination of the wheat germ agglutinin binding polypeptides of each subfraction reveals a decrease in the stain of two pore complex-lamina nucleoporins of 85 and 164 kDa and an increase in one of 93 kDa; this observation can be due to changes in the quantity and/or in the agglutinin binding capacity of the nucleoporin as a result of thioacetamide administration. In view of the participation of nucleoporins in the nucleocytoplasmic transport, the changes observed suggest a relationship between changes of some O-linked N-acetyl glucosamine polypeptides components of the nuclear pore complex and the altered transport of some RNA species observed after thioacetamide administration.


Asunto(s)
Animales , Masculino , Ratas , Carcinógenos/farmacología , Hígado/citología , Proteínas Nucleares/efectos de los fármacos , Péptidos/efectos de los fármacos , Tioacetamida/farmacología , Membrana Nuclear/química , Membrana Nuclear/metabolismo , Proteínas Nucleares/química , Péptidos/química , Ratas Sprague-Dawley
9.
Rev. Inst. Med. Trop. Säo Paulo ; 27(5): 229-37, set.-out. 1985. tab
Artículo en Inglés | LILACS | ID: lil-27057

RESUMEN

Em agosto de 1983, os Autores, estudaram 36 doentes com infecçäo causada pelo Plasmodium falciparum e 14 indivíduos normais, nascidos na regiäo de Humaitá, que nunca tiveram malária, sem esplenomegalia, com exame parasitológico de sangue e hemaglutinaçäo passiva negativas. Todos eles foram submetidos à observaçäo clínica completa, exame hematológico, exame parasitológico de sangue e tipagem de linfócitos. Os linfócitos foram isolados e congelados em nitrogênio líquido, para posterior tipagem pela formaçäo de rosetas. Os doentes foram classificados em dois grupos de acordo com a presença (13 doentes), ou ausência (23 doentes) de gametócitos antes do tratamento. Houve predomínio de formas graves no grupo de doentes sem gametócitos. Os resultados mostraram diminuiçäo do número de linfócitos T em ambos os grupos de doentes, com ou sem gametócitos antes do tratamento, enquanto que o número de linfócitos B foi normal apenas no grupo de doentes com gametócitos. Essas observaçöes, assim como as que foram relatadas pelos Autores anteriormente, permitem associar a presença de gametócitos circulantes com o número normal de células B em doentes com formas leves de malária causada pelo Plasmodium falciparum


Asunto(s)
Humanos , Leucocitos/inmunología , Linfocitos/inmunología , Malaria/sangre , Brasil , Cloroquina/tratamiento farmacológico , Clindamicina/tratamiento farmacológico , Recuento de Leucocitos , Malaria/tratamiento farmacológico , Plasmodium falciparum
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