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1.
J Ment Health ; : 1-8, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38845178

RESUMO

BACKGROUND: Mental illnesses and mental health challenges have become increasingly pervasive among Chinese university students. However, the utilization rate of mental health services is low among students. AIMS: We aimed to explore Chinese university students' help-seeking behaviors to understand how they deal with mental health challenges and use the results to inform the development of effective mental health promotion initiatives. METHODS: In this study, we conducted 13 focus group interviews with students in six universities in Jinan, China, including 91 (62%) female students and 56 (38%) male students. We drew on the Theory of Planned Behaviors to guide our thematic analysis to gain a contextual understanding of participants' accounts on help-seeking. RESULTS: Our results have depicted the help-seeking patterns of Chinese university students and show that there are four major behaviors which are self-reliance, seeking support from peers and families, seeking professional support, and accessing virtual mental health care. CONCLUSION: Results from this study can be used to inform the development of mental health literacy programming for students in universities that share similar contexts, and the study has also opened up a new space for using qualitative approaches to study mental health needs and access to care in diverse populations.

5.
Phytomedicine ; 44: 56-64, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29895493

RESUMO

BACKGROUND: Pancreatic cancer, associated with poor prognosis and low survival rate, has been the fourth leading cause of cancer-related death in the US. Although gemcitabine (Gem) is the first-line chemotherapeutic drug in the management of pancreatic cancer, the median survival extension is only 1.5 months, indicating unsatisfactory clinical results. Therefore, exploring agents that can enhance the anti-cancer activity of Gem would be an attractive strategy. PURPOSE: Our previous studies have demonstrated that eriocalyxin b (EriB), an ent­kaurane diterpenoid isolated from Isodon eriocalyx (Dunn.) Hara, possesses anti-pancreatic cancer effects, thus acting as a potential therapeutic agent. In this study, we further investigated whether EriB or the ethanol extract of I. eriocalyx (Isodon) could potentiate the cytotoxic activity of Gem in human pancreatic adenocarcinoma cells. In addition, the mechanism associated with their effects was also studied. METHODS: The anti-proliferation effect was assessed by MTT assay and Ki-67 immunostaining. The combination effect (addition, synergism and antagonism) of various agents was calculated by the Calcusyn software (Biosoft), utilizing the T.C. Chou Method. Apoptosis was detected using Annexin V and PI double staining followed by quantitative flow cytometry. Protein expression regulated by various treatments was analyzed by western blotting. RESULTS: The combination index revealed that Gem and EriB (or Isodon extract) had synergistic anti-proliferative effect. Both cellular apoptotic and anti-proliferative effects of Gem were significantly increased after combination with EriB (or Isodon extract). The underlying mechanisms involved in the combination effects were elucidated, which include: (1) increased activation of the caspase cascade; (2) reduction of PDK1 and AKT phosphorylation; (3) induction of JNK phosphorylation by Isodon and Gem combination. CONCLUSION: Gem and EriB (or Isodon extract) taken together in combination regulated PDK1/AKT1/caspase and JNK signaling and promoted apoptosis synergistically, which may contribute to the much increased anti-proliferative activity compared to either agent alone.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Diterpenos/farmacologia , Isodon/química , Neoplasias Pancreáticas/tratamento farmacológico , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/patologia , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Linhagem Celular Tumoral , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Diterpenos/administração & dosagem , Humanos , Sistema de Sinalização das MAP Quinases , Neoplasias Pancreáticas/patologia , Fosforilação/efeitos dos fármacos , Extratos Vegetais/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Piruvato Desidrogenase Quinase de Transferência de Acetil , Gencitabina
8.
Curr Mol Med ; 14(5): 673-89, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24894173

RESUMO

Thiol-containing antioxidant systems play an important role in regulating cellular redox homeostasis. Several anti-cancer agents act by targeting these systems by inducing the production of reactive oxygen species (ROS). Our earlier studies have shown that Eriocalyxin B (EriB), a diterpenoid isolated from Isodon eriocalyx, possesses anti-pancreatic tumour activities in vitro and in vivo. The present study further demonstrated that only thiol-containing antioxidants, N-acetylcysteine (NAC) or dithiothreitol (DTT), inhibited EriB-induced cytotoxicity and apoptosis. EriB suppressed the glutathione and thioredoxin antioxidant systems, thus increasing the intracellular ROS levels and regulating the MAPK, NFκB pathways. Treatment with EriB depleted the intracellular thiol-containing proteins in CAPAN-2 cells. In vivo studies also showed that EriB treatment (2.5 mg/kg) reduced the pancreatic tumour weights significantly in nude mice with increased superoxide levels. Taken together, our results shed important new light on the molecular mechanisms of EriB acting as an apoptogenic agent and its therapeutic potential for pancreatic cancer.


Assuntos
Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Diterpenos/farmacologia , Diterpenos/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Glutationa/metabolismo , Humanos , Masculino , Camundongos , Camundongos Nus , Espécies Reativas de Oxigênio/metabolismo , Neoplasias Pancreáticas
9.
Phytomedicine ; 21(4): 391-9, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24192211

RESUMO

Danshen and Gegen are two commonly used Chinese herbal medicines for treatment of cardiovascular diseases. The aim of the present study was to elucidate the combination effects of these two herbs on cerebral vascular tone and their underlying mechanisms of actions. Basilar artery rings were obtained from rats and precontracted with U46619. Cumulative administrations of aqueous extracts of Danshen, Gegen, or the two herbs combined (DG; ratio 7:3) produced concentration-dependent relaxation of the artery rings. Statistical analysis on these findings produced a combination index (CI) of 1.041 at ED50, which indicates the two herbs produced additive vasodilator effects when used as a combined decoction. Removal of the endothelium had no effect on the vasodilator properties of Danshen, Gegen, and DG. However, their maximum effects (Imax) were significantly blunted by a KATP channel inhibitor glibenclamide, a non-selective K(+) channel inhibitor tetraethylammonium (TEA), and by a combination of K(+) channel inhibitors (glibenclamide+TEA+iberiotoxin+4-aminopyridine+barium chloride). In addition, Danshen, Gegen, and DG produced augmentation of KATP currents and inhibited Ca(2+) influx in vascular smooth muscle cells isolated from rat basilar arteries. Furthermore, these agents inhibited CaCl2-induced contraction in the artery rings. In conclusion, the present study showed that Danshen and Gegen produced additive vasodilator effects on rat cerebral basilar arteries. These effects were independent of endothelium-derived relaxant factors (EDRF), but required the opening of KATP channels and inhibition of Ca(2+) influx in the vascular smooth muscle cells. It is suspected that the cerebral vasodilator effects of Danshen and Gegen produced either on their own or in combination, can help patients with obstructive cerebrovascular diseases.


Assuntos
Artéria Basilar/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Vasodilatação/efeitos dos fármacos , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico , Animais , Canais de Cálcio/efeitos dos fármacos , Endotélio Vascular/efeitos dos fármacos , Canais KATP/efeitos dos fármacos , Microscopia Confocal , Pueraria , Ratos , Salvia miltiorrhiza
10.
Phytomedicine ; 20(7): 611-4, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23541215

RESUMO

Increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) worldwide with limited therapeutic options is a growing public health concern. Natural products have been shown to possess antibacterial actions against MRSA. Flavonoids from natural products have been shown to possess antibacterial actions against MRSA by antagonizing its resistance mechanisms. Diosmin and diosmetin are natural flavonoids found in a variety of citrus fruits. The aim of this study was to investigate whether diosmin and diosmetin could inhibit the growth of MRSA and the in vitro enzymatic activity of a newly discovered MRSA drug target, pyruvate kinase (PK). By using a panel of MRSA strains with known resistant mechanisms, neither diosmin nor diosmetin was shown to possess direct antibacterial activities against all tested MRSA strains. However, in checkerboard assay, we found that diosmetin together with erythromycin, could synergistically inhibit the growth of ABC-pump overexpressed MRSA-RN4220/pUL5054, and time kill assay also showed that the antibacterial activities of diosmetin with erythromycin were bactericidal. Diosmetin was further shown to significantly suppress the MRSA PK activities in a dose dependent manner. In conclusion, the inhibition of MRSA PK by diosmetin could lead to a deficiency of ATP and affect the bacterial efflux pump which might contribute to the antibacterial actions of diosmetin against MRSA.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Antibacterianos/farmacologia , Eritromicina/farmacologia , Flavonoides/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Piruvato Quinase/antagonistas & inibidores , Trifosfato de Adenosina/metabolismo , Diosmina/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Staphylococcus aureus Resistente à Meticilina/metabolismo , Testes de Sensibilidade Microbiana
11.
Artigo em Inglês | MEDLINE | ID: mdl-23533460

RESUMO

Introduction. Hypertension in association with diabetes (DM), renal impairment (RI), and left ventricular hypertrophy (LVH) increases the risk of future cardiovascular events. We hypothesize, traditional herbal medicines Danshen and Gegen (D&G) have beneficial effects on atherogenesis in these high-risk hypertensive subjects. Subjects and Methods. 90 asymptomatic hypertensive subjects associated with LVH (63.3%), DM (62.2%), or RI (30%) were randomized to receive D&G herbal capsules 1 gm/day, 2 gm/day, or identical placebo capsules in double-blind and parallel fashion for 12 months. Brachial flow-mediated dilation (endothelium-dependent dilation, FMD) and carotid intima-media thickness (IMT) were measured by ultrasound. All data were analyzed using the Statistical Package for Social Sciences in Windows 16.0. Results. Their mean age was 55 ± 8 years, and 74.4% were male. After 12 months of adjunctive therapies and compared with baseline, there were no significant changes in blood pressure, heart rate, hematological, glucose, and creatinine profiles in both placebo and D&G groups. FMD improved significantly during D&G (P = 0.0001) and less so after placebo treatment (P = 0.001). There was a mild but significant decrease in carotid IMT after D&G (P < 0.001) but no significant changes after placebo. A trend of better improvement in FMD after higher versus lower D&G dosages was seen. D&G were well tolerated, with no significant adverse events or blood biochemistry changes. Conclusion. D&G adjunctive treatment was well tolerated and significantly improved atherogenesis in high-risk hypertensive patients, with potential in primary atherosclerosis prevention.

14.
Phytother Res ; 26(10): 1547-54, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22359405

RESUMO

Chinese herbal medicine has long been used as a treatment for wounds. However, the underlying cellular and molecular mechanisms remain largely unknown. In this study it was shown that the proliferation of keratinocytes, which is known to play an important role in wound healing as the major cell type in the epidermis, was promoted by three herbal extracts/natural compounds: NF3 (an extract from the mixture of Radix Astragali (RA) and Radix Rehmanniae (RR) in the ratio of 2:1), stachyose (an isolated compound from Radix Rehmanniae) and extract P2-2 (a sub-fraction from the extract of Radix Astragali). The effect of the herbal extracts/natural compounds on the growth of keratinocytes was not influenced by a high glucose level, a condition similar to diabetic patients who usually suffer from diabetic foot ulcers. Real time RT-PCR results showed that the expression of epidermal growth factor (EGF) receptor, but not transforming growth factor-ß (TGF-ß) receptor, was up-regulated by NF3. Moreover, treatments with the EGF receptor kinase inhibitor AG1478 and the MEK inhibitor U0126 resulted in the diminishment of the effect of the three herbal extracts/natural compounds on keratinocyte proliferation, indicating that EGF receptor might have a significant role in this action. This study has further elucidated the molecular mechanism under which herbal extracts/natural compounds exert their effects on the wound healing process.


Assuntos
Proliferação de Células/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Queratinócitos/efeitos dos fármacos , Extratos Vegetais/farmacologia , Astrágalo/química , Células Cultivadas , Receptores ErbB/metabolismo , Humanos , Oligossacarídeos/farmacologia , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Rehmannia/química , Regulação para Cima
15.
Arch Toxicol ; 86(5): 741-52, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22349056

RESUMO

Polyphyllin D (PD) is a potent anticancer agent isolated from a traditional medicinal herb Paris polyphylla that has been used in China for many years to treat cancer. PD is not a substrate of p-glycoprotein, and it can bypass the multi-drug resistance in cancer cell line R-HepG2. However, the effect of PD on the induction of cell death in human erythrocytes remains unknown. Given that PD is a small molecule that can depolarize the mitochondrial membrane potential and release apoptosis-inducing factor (AIF) in isolated mitochondria, we hypothesized that the apoptogenic effect of PD in human erythrocytes devoid of mitochondria would be minimal. This study therefore tried to evaluate the in vitro effect of PD on hemolysis and apoptosis in human erythrocytes. Apoptosis in human red blood cells (RBCs), also known as eryptosis or erythroptosis, after PD treatment was determined by flow cytometry and confocal microscopy for the phosphatidyl-serine externalization and other apoptosis feature events. False to our prediction, PD caused hemolysis and eryptosis/erythroptosis in human RBCs. Mechanistically, elevation in the cytosolic Ca²âº ion level seems to be a key but not the only mediator in the PD-mediated eryptosis/erythroptosis because depletion of the external Ca²âº could not eliminate the PD effect. Also, PD was able to permeabilize the membrane of RBC ghosts in a way similar to digitonin. Taken together, we report here for the first time the toxicity of PD in human RBCs as well as its underlying mechanism for the hemolysis and eryptosis/erythroptosis.


Assuntos
Apoptose/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Diosgenina/análogos & derivados , Eritrócitos/efeitos dos fármacos , Cálcio/metabolismo , Caspase 3/metabolismo , Tamanho Celular/efeitos dos fármacos , Células Cultivadas , Citosol/efeitos dos fármacos , Citosol/metabolismo , Diosgenina/farmacologia , Diosgenina/toxicidade , Eritrócitos/metabolismo , Eritrócitos/patologia , Humanos , Membranas Mitocondriais/efeitos dos fármacos , Saponinas
16.
Phytomedicine ; 19(6): 535-44, 2012 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-22261394

RESUMO

The present study investigated the effects of Radix Astragali (RA) and Radix Rehmanniae (RR), the major components of an anti-diabetic foot ulcer herbal formula (NF3), on the metabolism of model probe substrates of human CYP isoforms, CYP1A2, CYP2C9, CYP2D6, CYP2E1 and CYP3A4, which are important in the metabolism of a variety of xenobiotics. The effects of RA or RR on human CYP1A2 (phenacetin O-deethylase), CYP2C9 (tolbutamide 4-hydroxylase), CYP2D6 (dextromethorphan O-demethylase), CYP2E1 (chlorzoxazone 6-hydroxylase) and CYP3A4 (testosterone 6ß-hydroxylase) activities were investigated using pooled human liver microsomes. NF3 competitively inhibited activities of CYP2C9 (IC(50)=0.98mg/ml) and CYP3A4 (IC(50)=0.76mg/ml), with K(i) of 0.67 and 1.0mg/ml, respectively. With specific human CYP2C9 and CYP3A4 isoforms, NF3 competitively inhibited activities of CYP2C9 (IC(50)=0.86mg/ml) and CYP3A4 (IC(50)=0.88mg/ml), with K(i) of 0.57 and 1.6mg/ml, respectively. Studies on RA or RR individually showed that RR was more important in the metabolic interaction with the model CYP probe substrates. RR dose-dependently inhibited the testosterone 6ß-hydroxylation (K(i)=0.33mg/ml) while RA showed only minimal metabolic interaction potential with the model CYP probe substrates studied. This study showed that RR and the NF3 formula are metabolized mainly by CYP2C9 and/or CYP3A4, but weakly by CYP1A2, CYP2D6 and CYP2E1. The relatively high K(i) values of NF3 (for CYP2C9 and CYP3A4 metabolism) and RR (for CYP3A4 metabolism) would suggest a low potential for NF3 to cause herb-drug interaction involving these CYP isoforms.


Assuntos
Pé Diabético/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Fitoterapia , Rehmannia/química , Astrágalo , Astragalus propinquus , Citocromo P-450 CYP1A2/metabolismo , Citocromo P-450 CYP2D6/metabolismo , Citocromo P-450 CYP2E1/metabolismo , Avaliação de Medicamentos , Humanos , Oxigenases de Função Mista/metabolismo , Extratos Vegetais/farmacologia
17.
J Ethnopharmacol ; 139(1): 294-304, 2012 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-22120017

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Gegen (root of Pueraria lobata) is used in traditional Chinese medicine for treatment of cardiovascular diseases. In this study, the relaxant actions of three of its isoflavonoids; puerarin, daidzein, and daidzin, were investigated on rat-isolated cerebral basilar artery. MATERIALS AND METHODS: Rat basilar artery rings were precontracted with 100 nM U46619. Involvement of endothelium-dependent mechanisms was investigated by mechanical removal of the endothelium and inhibitors of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzymes. Adenylyl cyclase- and guanylyl cyclase-dependent pathways were investigated using their respective inhibitors 9-(tetrahydro-2-furanyl)-9H-purine-6-amine (SQ22536) and 1H-[1,2,4]oxadiazolo [4,3-[alpha]]-quinoxalin-1-one (ODQ). K(+) channels were investigated by pretreatment of the artery rings with various K(+) channel inhibitors, and Ca(2+) channels were investigated in artery rings incubated with Ca(2+)-free buffer and primed with 100 nM U46619 for 5 min prior to adding CaCl(2) to elicit contraction. RESULTS: Puerarin, daidzein, and daidzin produced concentration-dependent relaxation of the artery rings with concentration that produced 50% inhibition (IC(50)) of 304 ± 49 µM, 20 ± 7 µM, and 140 ± 21 µM, respectively. Removal of the endothelium produced no change on their vasorelaxant responses except the maximum response (I(max)) to puerarin was inhibited by 28%. The NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME; 100 µM) also produced 45% inhibition on the puerarin-induced vasorelaxant response, but not the COX inhibitor flurbiprofen (10 µM). SQ22536 (100 µM) and ODQ (100µM) did not affect the vasodilator responses to puerarin, daidzein and daidzin, but glibenclamide (1µM), tetraethylammonium (TEA, 100mM) or a combination of K(+) channel inhibitors (100nM iberiotoxin+1mM 4-aminopyridine+100 µM barium chloride+1 µM glibenclamide+100mM TEA) reduced their I(max). The contractile response to CaCl(2) was attenuated by 61% and 34% in the presence of daidzein and daidzin, respectively, whereas, puerarin did not significantly affect the contraction. CONCLUSIONS: The vasorelaxant action of daidzein and daidzin involved opening of K(+) channels and inhibition of Ca(2+) influx in the vascular smooth muscle cells. There is no evidence supporting involvement of endothelium-derived relaxing factors (EDRFs) in their actions. In contrast, puerarin produced vasodilatation via an endothelium-dependent mechanism involving nitric oxide production and an endothelium-independent pathway mediated by the opening of K(+) channels. The cerebral vasodilator activities of all these three isoflavonoids may be beneficial to patients with obstructive cerebrovascular diseases.


Assuntos
Artéria Basilar/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Flavonoides/farmacologia , Raízes de Plantas , Pueraria , Vasodilatadores/farmacologia , Animais , Artéria Basilar/fisiologia , Cálcio/fisiologia , Medicamentos de Ervas Chinesas/isolamento & purificação , Flavonoides/isolamento & purificação , Técnicas In Vitro , Masculino , Óxido Nítrico/fisiologia , Canais de Potássio/fisiologia , Ratos , Ratos Sprague-Dawley , Vasodilatação/efeitos dos fármacos , Vasodilatadores/isolamento & purificação
18.
J Ethnopharmacol ; 138(1): 175-83, 2011 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-21924338

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Salviae Miltiorrhizae Radix (Danshen) and Puerariae Lobatae Radix (Gegen) are principal herbs have long been used in combination for treating cardiovascular disease. AIMS OF STUDY: Danshen and Gegen in the ratio of 7:3 (DGW) have significantly reduced the carotid intimal-media thickening (IMT) in patients in our previous clinical study. In the present study, we have demonstrated the mechanisms on IMT reduction by investigating its key processes on both vascular smooth muscle cell (vSMC) and endothelial cells. MATERIALS AND METHODS: The anti-proliferative effects of DGW on platelet-derived growth factor (PDGF) induced vSMC proliferation were studied by cell proliferation, cell cycle distribution, p-ERK and cyclin D expression level. The anti-migratory effect of DGW was investigated by using transwell apparatus. For human umbilical endothelial cells (HUVEC), the inhibitory effects of DGW on TNF-alpha induced cell adhesion, cell adhesion molecules expression, MCP-1 and IL-6 production were investigated. RESULTS: DGW significantly inhibited A7r5 proliferation and exhibited G1/S cell cycle arrest by suppressing both p-ERK and cyclin D expression. Moreover, DGW showed anti-migratory effect against PDGF-induced A7r5 migration. In addition, DGW inhibited the cell adhesion as well as the expression of ICAM-1 and VCAM-1, the production of MCP-1 but not IL-6 in TNF-α stimulated HUVECs. CONCLUSIONS: Our study provided strong scientific evidence on IMT reduction in patients by modulating the key atherogenic events in both vSMC and endothelial cells.


Assuntos
Aterosclerose/prevenção & controle , Medicamentos de Ervas Chinesas/farmacologia , Endotélio Vascular/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Fitoterapia , Pueraria , Salvia miltiorrhiza , Aterosclerose/metabolismo , Fenômenos Fisiológicos Celulares/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quimiocina CCL2/metabolismo , Ciclina D/metabolismo , Medicamentos de Ervas Chinesas/uso terapêutico , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Endotélio Vascular/citologia , Endotélio Vascular/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células Endoteliais da Veia Umbilical Humana , Humanos , Molécula 1 de Adesão Intercelular/metabolismo , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Raízes de Plantas , Túnica Íntima/citologia , Túnica Íntima/efeitos dos fármacos , Túnica Íntima/metabolismo , Túnica Média/citologia , Túnica Média/efeitos dos fármacos , Túnica Média/metabolismo , Molécula 1 de Adesão de Célula Vascular/metabolismo
19.
J Ethnopharmacol ; 137(3): 1366-72, 2011 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-21855622

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Radix Salviae miltiorrhizae (Danshen) and Radix Puerariae lobatae (Gegen) have long been used in traditional Chinese Medicine and serve as the principal herbs in treating cardiovascular disease. AIMS OF THE STUDY: In the present study, an aqueous extract comprising Danshen and Gegen in the ratio of 7:3 (DG) was investigated for its anti-hypertension in vivo and vasodilative activities ex vivo. MATERIALS AND METHODS: The anti-hypertensive effect of DG extract was investigated in spontaneously hypertensive rat (SHR) by measuring systolic blood pressure (SBP). Oral administration of DG extract was started at age of 6 weeks and 14 weeks for the preventive and therapeutic studies, respectively. Blood pressure was measured by tail-cuff method biweekly for 12 weeks. The ex vivo vasodilative activities of DG extract, its dependency on endothelium and the involvement of nitric oxide, prostacyclin and potassium channels were investigated using isolated rat aorta ring in organ bath. RESULTS: For in vivo study, systolic blood pressure was significantly reduced in DG extract-treated groups (90.2 and 300 mg/kg) as compared with the SHR control in both preventive and therapeutic studies. However, DG extract was unable to suppress or delay the onset of hypertension in the preventive study. For ex vivo study, the results showed that DG extract induced a concentration-dependent relaxation in aorta and persisted response was observed with the removal of endothelium. Besides, pretreatment with a non-selective potassium channel inhibitor tetraethylammonium (TEA) also significantly inhibited DG extract-induced vasodilation. Further investigations on specific potassium channel blockers revealed that ATP-sensitive potassium (K(ATP)) channel inhibitor glibenclamide, inward rectifier potassium (Kir) inhibitor barium chloride and voltage-dependent potassium (K(v)) channel inhibitor 4-aminopyridine, but not BK(Ca) channel inhibitor iberiotoxin, exerted significant inhibition on DG extract-induced vasodilation. CONCLUSIONS: The results of in vivo SHR animal model suggested that DG aqueous extract possessed blood pressure lowering effect on both pre- and post-hypertensive rats, which could be explained by its endothelium-independent vasodilation via the opening of K(ATP), Kir and K(v) channels.


Assuntos
Anti-Hipertensivos/farmacologia , Aorta Torácica/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Medicamentos de Ervas Chinesas/farmacologia , Hipertensão/tratamento farmacológico , Pueraria , Salvia miltiorrhiza , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , Administração Oral , Animais , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/isolamento & purificação , Aorta Torácica/metabolismo , Aorta Torácica/fisiopatologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/isolamento & purificação , Epoprostenol/metabolismo , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Hipertensão/prevenção & controle , Canais KATP/efeitos dos fármacos , Canais KATP/metabolismo , Masculino , Óxido Nítrico/metabolismo , Plantas Medicinais , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio Corretores do Fluxo de Internalização/efeitos dos fármacos , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana/efeitos dos fármacos , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Pueraria/química , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Ratos Sprague-Dawley , Salvia miltiorrhiza/química , Fatores de Tempo , Vasodilatadores/administração & dosagem , Vasodilatadores/isolamento & purificação
20.
J Ethnopharmacol ; 137(1): 767-73, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21782012

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Baicalein, the active constituent derived from Scutellaria baicalensis Georgi., has previously been shown to significantly restore the effectiveness of ß-lactam antibiotics and tetracycline against methicillin-resistant Staphylococcus aureus (MRSA). With multiple therapeutic benefits, the antibacterial actions of baicalein may also be involved in overcoming other bacterial resistance mechanisms. The aim of the present study was to further investigate antibacterial activities of baicalein in association with various antibiotics against selected Staphylococcus aureus strains with known specific drug resistance mechanisms. MATERIAL AND METHODS: A panel of clinical MRSA strains was used for further confirmation of the antibacterial activities of baicalein. The effect of baicalein on inhibiting the enzymatic activity of a newly discovered MRSA-specific pyruvate kinase (PK), which is essential for Staphylococcus aureus growth and survival was also examined. RESULTS: In the checkerboard dilution test and time-kill assay, baicalein at 16 µg/ml could synergistically restore the antibacterial actions of ciprofloxacin against the NorA efflux pump overexpressed SA-1199B, but not with the poor NorA substrate, pefloxacin. Moreover, synergistic effects were observed when baicalein was combined with ciprofloxacin against 12 out of 20 clinical ciprofloxacin resistant strains. For MRSA PK studies, baicalein alone could inhibit the enzymatic activity of MRSA PK in a dose-dependent manner. CONCLUSION: Our results demonstrated that baicalein could significantly reverse the ciprofloxacin resistance of MRSA possibly by inhibiting the NorA efflux pump in vitro. The inhibition of MRSA PK by baicalein could lead to a deficiency of ATP which might further contribute to the antibacterial actions of baicalein against MRSA.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Ciprofloxacina/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Flavanonas/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Piruvato Quinase/antagonistas & inibidores , Proteínas de Bactérias/genética , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Quimioterapia Combinada , Staphylococcus aureus Resistente à Meticilina/enzimologia , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Piruvato Quinase/metabolismo , Fatores de Tempo , Regulação para Cima
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