RESUMO
Mild cognitive impairments have been described in one-third of patients with Duchenne muscle dystrophy (DMD). DMD is characterized by progressive and irreversible muscle degeneration caused by mutations in the dystrophin gene and lack of the protein expression. Previously, we have reported altered concentrations of α7- and ß2-containing nicotinic acetylcholine receptors (nAChRs) in hippocampal membranes of dystrophic (mdx) mice. This suggests that alterations in the central cholinergic synapses are associated with dystrophin deficiency. In this study, we examined the release of acetylcholine (ACh) and the level of the vesicular ACh transporter (VAChT) using synaptosomes isolated from brain regions that normally have a high density of dystrophin (cortex, hippocampus and cerebellum), in control and mdx mice at 4 and 12months of age. ACh release evoked by nicotinic stimulation or K(+) depolarization was measured as the tritium outflow from superfused synaptosomes preloaded with [(3)H]-choline. The results showed that the evoked tritium release was Ca(2+)-dependent and mostly formed by [(3)H]-ACh. ß2-containing nAChRs were involved in agonist-evoked [(3)H]-ACh release in control and mdx preparations. In hippocampal synaptosomes from 12-month-old mdx mice, nAChR-evoked [(3)H]-ACh release increased by 57% compared to age-matched controls. Moreover, there was a 98% increase in [(3)H]-ACh release compared to 4-month-old mdx mice. [(3)H]-ACh release evoked by K(+) depolarization was not altered, while the VAChT protein level was decreased (19%) compared to that of age-matched controls. In cortical and cerebellar preparations, there was no difference in nAChR-evoked [(3)H]-ACh release and VAChT levels between mdx and age-matched control groups. Our previous findings and the presynaptic alterations observed in the hippocampi of 12-month-old mdx mice indicate possible dysfunction of nicotinic cholinergic synapses associated with dystrophin deficiency. These changes may contribute to the cognitive and behavioral abnormalities described in dystrophic mice and patients with DMD.
Assuntos
Acetilcolina/metabolismo , Distrofina/deficiência , Distrofina/fisiologia , Hipocampo/metabolismo , Animais , Western Blotting , Cerebelo/efeitos dos fármacos , Cerebelo/crescimento & desenvolvimento , Cerebelo/metabolismo , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/crescimento & desenvolvimento , Córtex Cerebral/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/crescimento & desenvolvimento , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Antagonistas Nicotínicos/farmacologia , Cloreto de Potássio/metabolismo , Receptores Nicotínicos/metabolismo , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo , Proteínas Vesiculares de Transporte de Acetilcolina/metabolismoRESUMO
Cecropia glazioui Sneth (Cecropiaceae) is used in folk medicine in tropical and subtropical Latin America as cardiotonic, diuretic, hypotensive, anti-inflammatory and anti-asthmatic. The hypotensive/antihypertensive activity of the plant aqueous extract (AE) and isolated butanolic fraction (BuF) has been confirmed and putatively related to calcium channels blockade in vascular smooth musculature [Lapa, A.J., Lima-Landman, M.T.R., Cysneiros, R.M, Borges, A.C.R., Souccar, C., Barreta, I.P., Lima, T.C.M., 1999. The Brazilian folk medicine program to validate medicinal plants - a topic in new antihypertensive drug research. In: Hostettman, K., Gupta, M.P., Marston, A. (Eds.), Proceedings Volume, IOCD/CYTED Symposium, Panamá City, Panamá, 23-26 February 1997. Chemistry, Biological and Pharmacological Properties of Medicinal Plants from the Americas. Harwood Academic Publishers, Amsterdam, pp. 185-196; Lima-Landman, M.T., Borges, A.C., Cysneiros, R.M., De Lima, T.C., Souccar, C., Lapa, A.J., 2007. Antihypertensive effect of a standardized aqueous extract of Cecropia glaziovii Sneth in rats: an in vivo approach to the hypotensive mechanism. Phytomedicine 14, 314-320]. Bronchodilation and antidepressant-like activities of both AE and BuF have been also shown [Delarcina, S., Lima-Landman, M.T., Souccar, C., Cysneiros, R.M., Tanae, M.M., Lapa, A.J., 2007. Inhibition of histamine-induced bronchospasm in guinea pigs treated with Cecropia glaziovi Sneth and correlation with the in vitro activity in tracheal muscles. Phytomedicine 14, 328-332; Rocha, F.F., Lima-Landman, M.T., Souccar, C., Tanae, M.M., De Lima, T.C., Lapa, A.J., 2007. Antidepressant-like effect of Cecropia glazioui Sneth and its constituents -in vivo and in vitro characterization of the underlying mechanism. Phytomedicine 14, 396-402]. This study reports the antiulcer and antisecretory gastric acid activities of the plant AE, its BuF and isolated compounds with the possible mechanism involved. Both AE and BuF were assayed on gastric acid secretion of pylorus-ligated mice, on acute models of gastric mucosal lesions, and on rabbit gastric H(+), K(+)-ATPase preparations. Intraduodenal injection of AE or BuF (0.5-2.0g/kg, i.d) produced a dose-related decrease of the basal gastric acid secretion in 4-h pylorus-ligated mice. At 1.0g/kg, BuF decreased the volume (28%) and total acidity (33%) of the basal acid secretion, and reversed the histamine (2.5mg/kg, s.c.)- or bethanecol (1.0mg/kg, s.c.)-induced acid secretion to basal values, indicating inhibition of the gastric proton pump. Pretreatment of mice with the BuF (0.05-0.5g/kg, p.o.) protected against gastric mucosal lesions induced by 75% ethanol, indomethacin (30mg/kg, s.c.) or restraint at 4 degrees C. BuF also decreased the gastric H(+), K(+)-ATPase activity in vitro proportionately to the concentration (IC(50)=58.8microg/ml). The compounds isolated from BuF, consisting mainly of cathechins, procyanidins and flavonoids [Tanae, M.M., Lima-Landman, M.T.R., De Lima, T.C.M., Souccar, C., Lapa, A.J., 2007. Chemical standardization of the aqueous extract of Cecropia glaziovii Sneth endowed with antihypertensive, bronchodilator, antacid secretion and antidepressant-like activities. Phytomedicine 14, 309-313], inhibited the in vitro gastric H(+), K(+)-ATPase activity at equieffective concentrations to that of BuF. The results indicate that C. glazioui constituents inhibit the gastric proton pump; this effect may account for the effective antisecretory and antiulcer activities of the standardized plant extract.
Assuntos
Cecropia/química , Fitoterapia , Extratos Vegetais/uso terapêutico , Inibidores da Bomba de Prótons/análise , Úlcera Gástrica/prevenção & controle , Animais , Antiácidos/análise , Feminino , Ácido Gástrico/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Extratos Vegetais/químicaRESUMO
The present study aimed to characterize the antidepressant-like effect of a standardized aqueous extract (AE) of Cecropia glazioui Sneth and its purified fractions on in vivo (forced swimming test), ex vivo (hippocampal monoamines levels) and in vitro (serotonin, noradrenaline and dopamine uptake) tests, searching for the active principles and the underlying mechanisms of action. Treatment with AE, or with its butanolic fraction (BuF), the latter rich in catechins, procyanidins and flavonoids, reduced the immobility of rats in the forced swimming test indicating an antidepressant-like effect. Biochemical analysis of the hippocampal neurotransmitters in BuF-treated rats showed significant increase in monoamines levels. BuF and six of its purified constituents inhibited the uptake of [(3)H]-serotonin, [(3)H]-dopamine and [(3)H]-noradrenaline by synaptosomes of different brain regions. Catechin, catechin (4alpha-->8) ent-catechin (Procyanidin B3 isomer) and epicatechin (4beta-->8) epicatechin (Procyanidin B2) were the most active compounds. Comparatively, the uptake of [(3)H]-noradrenaline was the most affected. These results show that the antidepressant-like effect promoted by C. glazioui extract is most likely due to the blockade of the monoamines uptake in the CNS.
Assuntos
Antidepressivos/química , Antidepressivos/farmacologia , Cecropia/química , Animais , Relação Dose-Resposta a Droga , Feminino , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Ratos , Serotonina/metabolismo , NataçãoRESUMO
To evaluate the effect of the standardized aqueous extract (AE) of Cecropia glaziovii Sneth on the plasma angiotensin I converting enzyme (ACE-EC 3.4.15.1) activity, rats were treated with a single dose of AE (1 g/kg, p.o.) or repeatedly (0.5 g/kg/bid, p.o.) for 60 days. Captopril (50 mg/kg, p.o.) was used as positive control on the same animals. The effects on the blood pressure were recorded directly from the femoral artery (single dose), or indirectly by the tail cuff method (repeated doses) in conscious rats. The plasma ACE activity was determined spectrofluorimetrically using Hypuril-Hystidine-Leucine as substrate. The arterial blood pressure, heart rate and plasma ACE activity were not significantly modified within 24 h after a single dose administration of AE. Comparatively, blood pressure in captopril treated rats was reduced by 7-16% and heart rate was increased by 10-20% from 30 min to 24 h after drug administration. ACE activity after captopril presented a dual response: an immediate inhibition peaking at 30 min and a slow reversal to 32% up-regulation after 24 h. To correlate the drug effects upon repeated administration of either compound, normotensive rats were separated in three groups: animals with high ACE (48.8+/-2.6 nmol/min/ml), intermediate ACE (39.4+/-1.4 nmol/min/ml) and low ACE (23.5+/-0.6 nmol/min/ml) activity, significantly different among them. Repeated treatment with AE reduced the mean systolic blood pressure (121.7+/-0.5 mm Hg) by 20 mm Hg after 14 days. The hypotension was reversed upon washout 60 days afterwards. Likely, repeated captopril administration decreased blood pressure by 20 mm Hg throughout treatment in all groups. After 30 days treatment with AE (0.5 g/kg/bid, p.o.) the plasma ACE activity was unchanged in any experimental group. After captopril (50 mg/kg/bid, p.o.) administration the plasma ACE activity was inhibited by 50% within 1 h treatment but it was up-regulated by 120% after 12 h in all groups. It is concluded that the hypotension produced by prolonged treatment with AE of C. glaziovii is unrelated to ACE inhibition.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Anti-Hipertensivos/farmacologia , Captopril/farmacologia , Fitoterapia , Extratos Vegetais/farmacologia , Urticaceae , Administração Oral , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Animais , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Captopril/administração & dosagem , Captopril/uso terapêutico , Feminino , Frequência Cardíaca/efeitos dos fármacos , Hipertensão/prevenção & controle , Peptidil Dipeptidase A/sangue , Extratos Vegetais/administração & dosagem , Extratos Vegetais/uso terapêutico , Folhas de Planta , Ratos , Ratos WistarRESUMO
This study reports the extraction process and standardization of the aqueous extract (AE) of a Cecropia species aiming its pharmacological characterization as a phytomedicine to be used in primary health care. The plant was originally collected in its environment, and was thereafter specially cultivated for the present work. To standardize the plant AE, several 2.0% tea of the dried leaves were prepared under controlled conditions and freeze dried. The AE (20% yield) was partitioned with n-butanol yielding the butanolic fraction (BuF; 1% yield). The activity of AE on vital organ functions (cardiovascular, respiratory, gastrointestinal and central nervous system) was determined in vivo. The effects of AE were compared to those of BuF in the same models and the relative potency determined. BuF was further evaluated in representative in vitro models to assess possible mechanisms of action. Chemical constituents of BuF were isolated in preparative HPLC columns yielding 10 highly purified compounds chemically identified as catechins (2), procyanidins (4), flavonoids (2), mixed sugars (1) and chlorogenic acid. All the compounds were identified by chemical analytic instrumentation (13C-NMR, 1H-NMR, LC-MS). Their relative concentrations in AE were ca 12% catechins, 19% procyanidins and 19% flavonoids. The pharmacological activity of the standardized AE is reported in accompanying papers.
Assuntos
Fitoterapia , Extratos Vegetais/farmacologia , Urticaceae , Animais , Antiácidos/administração & dosagem , Antiácidos/química , Antiácidos/farmacologia , Antiácidos/uso terapêutico , Antidepressivos/administração & dosagem , Antidepressivos/química , Antidepressivos/farmacologia , Antidepressivos/uso terapêutico , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/química , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Brasil , Broncodilatadores/administração & dosagem , Broncodilatadores/química , Broncodilatadores/farmacologia , Broncodilatadores/uso terapêutico , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Folhas de Planta , RatosRESUMO
Cecropia glaziovii Sneth is a common tree at the Southeastern Brazilian coast. As many other species of the genus, it shares the reputed folk use to treat heart failure, cough, asthma and bronchitis. The plant has been cultivated under controlled conditions and the 2% aqueous extract (AE) prepared with the dried leaves was standardized by its chemical contents on catechins, flavonoids and procyanidins. The present paper reports the antihypertensive activity of AE and of n-butanol fraction (BuF), an enriched semi-purified butanolic fraction used to isolate the main chemical constituents. Oral administration of AE and BuF induced hypotension in normotensive rats. The effect of AE (0.5 g/kg/bi, p.o.) was time and dose-dependent peaking at 2-3 weeks after daily administration. BuF was faster but not more active than AE. Both extracts decreased the hypertension of spontaneous hypertensive rats, the hypertension induced in rats by L-NAME treatment and that induced by constriction of one renal artery. The antihypertensive effect was maintained for as long as 60 days of treatment and was reversible upon drug washout at the same rate of its establishment. Acute i.v. administration of BuF to anesthetized rats induced a fast short-lasting hypotension and inhibited the pressor responses to noradrenaline, angiotensin I and angiotensin II by 40%. These results were indirect indications that the hypotension induced by AE is not related to ACE inhibition, increased NO synthesis, or specific blockade of alpha1 and AT1 receptors. It can be suggested that BuF interferes with the calcium handling mechanisms in smooth muscle cells and neurons. Intravenous injection of five out of nine compounds isolated from BuF produced immediate but short-lasting hypotension that does not correlate with the onset of the hypotension after oral treatment. This finding suggests that they may not be the compounds directly responsible for the delayed and sustained hypotension after per os administration of AE. The many compounds isolated from AE are under evaluation to determine its pharmacokinetics, mechanisms of action and interactions necessary to yield the plant effect. Although its mechanism is still unknown, AE seems to be an effective and safe antihypertensive phytomedicine.
Assuntos
Anti-Hipertensivos/farmacologia , Fitoterapia , Extratos Vegetais/farmacologia , Urticaceae , Administração Oral , Animais , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/química , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Relação Dose-Resposta a Droga , Hipertensão/prevenção & controle , Hipertensão Renal/prevenção & controle , Injeções Intravenosas , Masculino , Camundongos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Folhas de Planta , Ratos , Ratos WistarRESUMO
A standardized aqueous extract (AE) and a purified fraction (BuF) of Cecropia glaziovi Sneth leaves were tested in unrestrained guinea pigs challenged with histamine. Changes of the respiratory pressure and rate were recorded in a whole body plethysmograph before and after treatment. The concentration of histamine necessary to produce bronchospasm was increased by five-fold following administration of AE (1.0 g/kg p.o.), and by two-fold after treatment with the semi-purified procyanidin/flavonoids enriched BuF (0.1 g/kg p.o.). Both effects were blocked by previous treatment with propranolol (10.0 mg/kg i.p.). In vitro incubation of BuF (0.1-1.0 mg/ml) decreased by 13-55% the maximal response of guinea pig tracheal muscle to histamine, without significant change of EC50. The results confirmed old reports on the useful pulmonary effects of Cecropia extracts. The bronchodilation observed in vivo seems to be related to beta-adrenergic activity observed in vitro only with high concentrations of the purified extract.
Assuntos
Espasmo Brônquico/prevenção & controle , Broncodilatadores/farmacologia , Fitoterapia , Extratos Vegetais/farmacologia , Traqueia/efeitos dos fármacos , Urticaceae , Administração Oral , Animais , Espasmo Brônquico/induzido quimicamente , Broncodilatadores/administração & dosagem , Broncodilatadores/uso terapêutico , Relação Dose-Resposta a Droga , Cobaias , Histamina , Masculino , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Extratos Vegetais/uso terapêutico , Folhas de PlantaRESUMO
Freeze-dried aqueous extracts (AEs, 0.1-1g/kg body wt., p.o.) obtained from entire or selected parts of Stachytarpheta cayennensis were tested for their effects on gastric secretion, gastric motility, inflammation and pain in rodents, with the purpose of validating the plant's ethnomedical uses. The AE-Total, AE-Flowers and AE-Leaves but not AE-Stems inhibited the gastric acid secretion in pylorus-ligated rats with varying potency. Purification of AEs yielded the semipurifed fractions EtFs rich in iridoids. All the EtFs with exception of EtF-Stems inhibited gastric acid secretion of pylorus ligated mice. While AE-Total stimulated the intestinal transit of mice by 43%, AE-Leaves delayed it by 38%. These effects on intestinal transit were not observed when the EtFs were tested. Only AE-Leaves and AE-Flowers altered the gastric emptying of semisolids, increasing it by 45% and 69%, respectively. These results indicate that the compounds related to inhibition of gastric acid secretion and gastrointestinal motility are different. The AE-Total reduced abdominal writhing induced by acetic acid potently (ED50 value = 700 mg/kg, p. o.) without altering the writhes induced by acetylcholine. Attempts to identify the mechanism of analgesia were unsuccessful since the AE-Total did not show analgesic effects when tested in different models of pain such as formalin and capsaicin or the tail-flick test. Pretreatment of animals with AE-Total did not show antiinflammatory activity in any of the acute (paw edema induced by carrageenin, dextran or histamine, pleurisy induced by carrageenin and capsaicin-induced mouse ear edema) or chronic (air pouch) models used. No toxic signs were observed after administration of the different extracts up to 2 g/kg body wt., p.o. Collectively, the results confirmed folk information indicating presence of analgesic, mild laxative and potent inhibition of gastric secretion activities in the aqueous extracts of S. cayennensis. The results do not, however confirm the folk use of the plant as an antiinflammatory medicine.
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Verbenaceae/química , Animais , Feminino , Flores/química , Ácido Gástrico/metabolismo , Fármacos Gastrointestinais/farmacologia , Motilidade Gastrointestinal/efeitos dos fármacos , Inflamação/tratamento farmacológico , Medicina Tradicional , Camundongos , Dor/tratamento farmacológico , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Ratos , Ratos Wistar , Fatores de TempoRESUMO
Solanum paniculatum L. is used commonly in Brazilian folk medicine for the treatment of liver and gastrointestinal disorders. The freeze-dried aqueous extracts (WEs) obtained from distinct parts of the plant (flowers, fruits, leaves, stems and roots) were tested to determine their antiulcer and antisecretory gastric acid activities using mice. The aqueous extracts of roots, stems and flowers inhibited gastric acid secretion in pylorus-ligated mice with ED50 values of 418, 777 and 820 mg/kg body wt. (i.d.), respectively. Extracts of leaves (0.5-2 g/kg body wt., i.d.) did not affect gastric secretion, whereas fruit extracts (0.5-2 g/kg body wt., i.d.) stimulated gastric acid secretion. The stimulatory effect of the fruit extract was inhibited by pretreatment with atropine (5 mg/kg body wt., i.m.) but not with ranitidine (80 mg/kg body wt., i.p.) suggesting that the fruit extract activates the muscarinic pathway of gastric acid secretion. In contrast, administration of the root extract into the duodenal lumen inhibited histamine- and bethanechol-induced gastric secretion in pylorus-ligated mice. In addition, the aqueous extract of roots (ED50 value, 1.2 g/kg body wt., p.o.) protected the animals against production of gastric lesions subsequent to the hypersecretion induced in mice by stress following cold restraint. This effect was not reproduced when the lesions were induced by blockade of prostaglandins synthesis via subcutaneous injection of indomethacin. Thus, antiulcer activity of the plant extracts appears to be related directly to a potent anti-secretory activity. No toxic signs were observed following administration of different extracts up to 2 g/kg body wt., p.o. Collectively, the results validate folk use of Solanum paniculatum L. plant to treat gastric disorders.