Publications (29) View all
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Article: Combination of TNF-α, homocysteine and adenosine exacerbated cytotoxicity in human cardiovascular and cerebrovascular endothelial cells.
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ABSTRACT: Disruption to the vascular homoeostasis is detrimental in vascular diseases. This study examined how the combination of homocysteine, adenosine and tumor necrosis factor-alpha (TNF-α) influenced endothelial cell survival. In cultured human-derived cardiovascular (EA.hy926) and cerebrovascular (HBEC-5i) endothelial cells, cell death events were initiated by TNF-α (0.1-10 ng/mL) only when both homocysteine (0.5 mM) and adenosine (0.5 mM) were present. The accelerated cell death events induced by the combination were triggered through excessive apoptosis. This was evident by membrane phospholipid phosphatidylserine externalisation, cell shrinkage and DNA fragmentation, as well as an increase in the expressions and occurrence of active caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP) positive cells. Collectively, homocysteine, adenosine and TNF-α are interrelated in the survival of endothelial cells, and this co-existence should be considered in future drug development for cardiovascular and cerebrovascular diseases.Cellular Physiology and Biochemistry 08/2012; 30(3):805-14. · 2.86 Impact Factor -
Article: The protective effects of natural products on blood-brain barrier breakdown.
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ABSTRACT: The blood-brain barrier (BBB) is a protective fence between the central nervous system and the systemic circulation, and is essential for maintaining the normal homeostasis of the central nervous system. BBB breakdown is instigated in many neurological disorders such as Alzheimer's disease and multiple sclerosis. Recent literature has advanced the knowledge on the physiology and pathophysiology of BBB breakdown, including the attribution of detrimental inducers and signalling transduction cascades. Natural products, such as flavonoids, phenolic compounds, terpenes, alkaloids, lipids and phthalides have been reported to attenuate many neurological diseases by modulating the signalling transduction cascades associated with BBB breakdown. Understanding the activities of these natural products through the molecular mechanisms associated with BBB breakdown will offer considerable scope in the discovery and development of novel agents for preventing BBB breakdown and thus, the progression of neurological disorders.Current Medicinal Chemistry 02/2012; 19(12):1830-45. · 4.86 Impact Factor -
Article: Protective effects of ethanolic extract of Zingiber officinale rhizome on the development of metabolic syndrome in high-fat diet-fed rats.
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ABSTRACT: Metabolic syndrome, including obesity, dyslipidaemia, hyperglycaemia and insulin resistance that predisposes type 2 diabetes is a major disease problem around the world and a plethora of herbal medicines are claimed to be effective in controlling these disorders. The rhizome of Zingiber officinale (Zingiberaceae) is commonly used as a spice in various foods and beverages. Apart from its other traditional medical uses, Z. officinale has been used to control diabetes and dyslipidaemia. In the present study, the protective effects of an ethanolic extract of Z. officinale on the development of metabolic syndrome were investigated in a high-fat diet-fed rat model at doses of 100, 200 and 400 mg/kg body weight. The marked rise in body weights, glucose, insulin, total cholesterol, LDL cholesterol, triglycerides, free fatty acids and phospholipids in serum of the rats that followed 6 weeks of high-fat diet treatment were significantly reduced by Z. officinale treatment. However, no significant change in serum HDL cholesterol was observed either with high-fat diet or Z. officinale compared to both control groups. The present results provide scientific evidence to substantiate the traditional use of Z. officinale in preventing metabolic disorders.Basic & Clinical Pharmacology & Toxicology 06/2009; 104(5):366-73. · 2.18 Impact Factor -
Article: Role of serum- and glucocorticoid-inducible kinase SGK1 in glucocorticoid regulation of renal electrolyte excretion and blood pressure.
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ABSTRACT: The serum- and glucocorticoid-inducible kinase SGK1 was originally cloned as a glucocorticoid-regulated gene and later as a transcriptional target for mineralocorticoids. SGK1 regulates channels and transporters including the renal Na(+) channel ENaC. It contributes to mineralocorticoid regulation of renal Na(+) excretion and salt appetite. The present study explored the contribution of SGK1 to effects of glucocorticoids on mineral and electrolyte metabolism. SGK1-knockout mice (sgk1(-/-)) and their wild-type littermates (sgk1(+/+)) were analyzed in metabolic cages with or without treatment for 14 days with dexamethasone (3 mg/kg b.w., i.p.). Blood pressure was determined by the tail-cuff method. Prior to treatment fluid intake, urinary flow rate, urinary Na(+), K(+), phosphate and Cl(-) excretion, plasma electrolyte and glucose concentrations as well as blood pressure were similar in sgk1(-/-) and sgk1(+/+) mice. Dexamethasone did not significantly alter renal Na(+), K(+), Cl(-) and Ca(2+) excretion but decreased plasma Ca(2+) and phosphate concentration in sgk1(+/+) mice. The effect on Ca(2+) was significantly augmented and the effect on phosphate significantly blunted in sgk1(-/-) mice. Dexamethasone significantly increased fasting blood glucose concentrations in both genotypes. Dexamethasone increased blood pressure in sgk1(+/+) mice, an effect significantly blunted in sgk1(-/-) mice. The present observations disclose SGK1-sensitive glucocorticoid effects on calcium-phosphate metabolism and blood pressure.Kidney and Blood Pressure Research 02/2008; 31(4):280-9. · 1.46 Impact Factor -
Article: Antidiabetic and renoprotective effects of the chloroform extract of Terminalia chebula Retz. seeds in streptozotocin-induced diabetic rats
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ABSTRACT: Abstract Background Terminalia chebula (Combretaceae) has been widely used in Ayurveda for the treatment of diabetes. In the present investigation, the chloroform extract of T. chebula seed powder was investigated for its antidiabetic activity in streptozotocin-induced diabetic rats using short term and long term study protocols. The efficacy of the extract was also evaluated for protection of renal functions in diabetic rats. Methods The blood glucose lowering activity of the chloroform extract was determined in streptozotocin-induced (75 mg/kg, i.p.; dissolved in 0.1 M acetate buffer; pH 4.5) diabetic rats, after oral administration at the doses of 100, 200 and 300 mg/kg in short term study. Blood samples were collected from the eye retro-orbital plexus of rats before and also at 0.5, 1, 2, 4, 6, 8 and 12 h after drug administration and the samples were analyzed for blood glucose by using glucose-oxidase/peroxidase method using a visible spectrophotometer. In long term study, the extract (300 mg/kg) was administered to streptozotocin-induced diabetic rats, daily for 8 weeks. Blood glucose was measured at weekly intervals for 4 weeks. Urine samples were collected before the induction of diabetes and at the end of 8 weeks of treatments and analyzed for urinary protein, albumin and creatinine levels. The data was compared statistically using one-way ANOVA with post-hoc Dunnet's t -test. Results The chloroform extract of T. chebula seeds produced dose-dependent reduction in blood glucose of diabetic rats and comparable with that of standard drug, glibenclamide in short term study. It also produced significant reduction in blood glucose in long term study. Significant renoprotective activity is observed in T. chebula treated rats. The results indicate a prolonged action in reduction of blood glucose by T. chebula and is probably mediated through enhanced secretion of insulin from the β-cells of Langerhans or through extra pancreatic mechanism. The probable mechanism of potent renoprotective actions of T. chebula has to be evaluated. Conclusion The present studies clearly indicated a significant antidiabetic and renoprotective effects with the chloroform extract of T. chebula and lend support for its traditional usage. Further investigations on identification of the active principles and their mode of action are needed to unravel the molecular mechanisms involved in the observed effects.BMC Complementary and Alternative Medicine. 01/2006;
