Pyridylnidulin exerts anti-diabetic properties and improves non-alcoholic fatty liver disease in diet-induced obesity mice.

Introduction: Non-alcoholic fatty liver disease (NAFLD) is one of the metabolic disorders related to the pathophysiology of type 2 diabetes mellitus (T2DM). Therapeutic strategies are focused on the improvement of energy balance and lifestyle modification. Additionally, the derivative of the bioactive fungal metabolite is of interest to provide health benefits, especially in obese and pre-diabetic conditions. In our screening of anti-diabetic compounds from fungal metabolites and semisynthetic derivatives, a depsidone derivative, namely pyridylnidulin (PN), showed potent glucose uptake-inducing activity. The present study aimed to investigate the liver lipid metabolism and anti-diabetic properties of PN in diet-induced obesity mice. Methods: Male C57BL/6 mice were induced obesity and pre-diabetic conditions by dietary intervention with a high-fat diet (HFD) for 6 weeks. These obese mice were orally administered with PN (40 or 120 mg/kg), metformin (150 mg/kg), or vehicle for 4 weeks. Glucose tolerance, plasma adipocytokines, hepatic gene and protein expressions were assessed after treatment. Results: Improved glucose tolerance and reduced fasting blood glucose levels were found in the PN and metformin-treated mice. Additionally, hepatic triglyceride levels were consistent with the histopathological steatosis score regarding hepatocellular hypertrophy in the PN and metformin groups. The levels of plasma adipocytokines such as tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1) were reduced in the PN (120 mg/kg) and metformin-treated mice. In addition, hepatic gene expression involved in lipid metabolism, including lipogenic enzymes was significantly reduced in the PN (120 mg/kg) and metformin-treated mice. The increased protein expression levels of phosphorylated AMP-activated protein kinase (p-AMPK) was also found in PN and metformin-treated mice. Discussion: Considering the increased p-AMPK protein expression levels in PN and metformin-treated mice were revealed as the underlying mechanisms to improve metabolic parameters. These results suggested that PN provided the health benefit to slow the progression of NAFLD and T2DM in obese and pre-diabetic conditions.

The Finding of New In Vivo Metabolite Triptorelin (5-10) in Human Urine Using Liquid Chromatography Coupled with Ion Trap/Time-of-Flight Mass Spectrometry with Dimethyl Sulfoxide Additives in the Mobile Phase.

Triptorelin and leuprorelin are synthetic gonadotrophin-releasing hormones (GnRH) that are on the World Anti-Doping Agency (WADA) list of prohibited substances. To investigate the possible in vivo metabolites of triptorelin and leuprorelin in humans compared to previously reported in vitro metabolites, excreted urine from five patients treated with either triptorelin or leuprorelin was analyzed by liquid chromatography coupled with ion trap/time-of-flight mass spectrometry (LC/MS-IT-TOF). The addition of dimethyl sulfoxide (DMSO) to the mobile phase was found to enhance the detection sensitivity of certain GnRH analogs. The method was validated, and the limit of detection (LOD) was found at 0.02-0.08 ng/mL. Using this method, a novel new metabolite of triptorelin was discovered in the urine of all subjects up to 1 month after triptorelin administration, but it was not observed in the urine of subjects before drug administration. The limit of detection was estimated to be 0.05 ng/mL. The structure of the metabolite, triptorelin (5-10), is proposed from bottom-up mass spectrometry analysis. The discovery of in vivo triptorelin (5-10) can possibly be used as supporting evidence of triptorelin misuse in athletes.

Short-Term Growth Hormone Administration Mediates Hepatic Fatty Acid Uptake and De Novo Lipogenesis Gene Expression in Obese Rats.

Obesity has been linked to metabolic syndrome, type 2 diabetes, and non-alcoholic fatty liver disease (NAFLD). Obesity causes a decrease in growth hormone (GH) levels and an increase in insulin levels. Long-term GH treatment increased lipolytic activity as opposed to decreasing insulin sensitivity. Nonetheless, it is possible that short-term GH administration had no impact on insulin sensitivity. In this study, the effect of short-term GH administration on liver lipid metabolism and the effector molecules of GH and insulin receptors were investigated in diet-induced obesity (DIO) rats. Recombinant human GH (1 mg/kg) was then administered for 3 days. Livers were collected to determine the hepatic mRNA expression and protein levels involved in lipid metabolism. The expression of GH and insulin receptor effector proteins was investigated. In DIO rats, short-term GH administration significantly reduced hepatic fatty acid synthase (FASN) and cluster of differentiation 36 (CD36) mRNA expression while increasing carnitine palmitoyltransferase 1A (CPT1A) mRNA expression. Short-term GH administration reduced hepatic FAS protein levels and downregulated gene transcription of hepatic fatty acid uptake and lipogenesis, while increasing fatty acid oxidation in DIO rats. DIO rats had lower hepatic JAK2 protein levels but higher IRS-1 levels than control rats due to hyperinsulinemia. Our findings suggest that short-term GH supplementation improves liver lipid metabolism and may slow the progression of NAFLD, where GH acts as the transcriptional regulator of related genes.

Inhibitory effects of Thai herbal extracts on the cytochrome P450 3A-mediated the metabolism of gefitinib, lapatinib and sorafenib.

Herbal products are widely used in cancer patients via co-administration with chemotherapy. Previous studies have demonstrated that pharmacokinetic interactions between herbs and anticancer drugs exist due to inhibition of drug-metabolizing enzymes, particularly cytochrome P450s (CYPs). The aim of this study was to determine the inhibitory effects of Andrographis paniculata, Curcuma zedoaria, Ganoderma lucidum, Murdannia loriformis and Ventilago denticulata extracts on the metabolism of gefitinib, lapatinib and sorafenib. The activities of CYP3A in human liver microsome on the metabolism of gefitinib, lapatinib and sorafenib in the absence and presence of Thai herbal extracts were assayed using high-performance liquid chromatography analysis. Curcuma zedoaria extract potently inhibited CYP3A-mediated lapatinib and sorafenib metabolism with IC50 values of 4.18 ± 3.20 and 7.59 ± 1.23 µg/mL, respectively, while the metabolism of gefitinib was strongly inhibited by Murdannia loriformis and Ventilago denticulata extracts with IC50 values of 7.53 ± 2.87 and 7.06 ± 1.23 µg/mL, respectively. Andrographis paniculata and Ganoderma lucidum extracts had less effect on the metabolism of the tested anticancers (IC50 values >10 µg/mL). In addition, kinetic analysis of the ability of Curcuma zedoaria extract to inhibit CYP3A-mediated metabolism of anticancer drugs was best described by the noncompetitive and competitive inhibition models with Ki values of 20.08 and 11.55 µg/mL for the metabolism of gefitinib and sorafenib, respectively. The present study demonstrated that there were potential pharmacokinetic interactions between tyrosine kinase inhibitors and herbal extracts.

Sustained AT1R stimulation induces upregulation of growth factors in human cardiac fibroblasts via Gαq/TGF-ß/ERK signaling that influences myocyte hypertrophy.

Stimulation of angiotensin II receptor (ATR) with angiotensin II (Ang II) accelerates cardiac fibroblast activation, resulting in upregulation of cytokines and growth factors. Growth factors were strongly upregulated in animal models of myocardial fibrosis and hypertrophy as well as patients with heart failure. Nevertheless, the signal transduction of ATR for upregulation of growth factors in human cardiac fibroblasts contributing to myocyte hypertrophy have not fully understood. Long-term Ang II treatment of human cardiac fibroblasts provokes the synthesis and secretion of connective tissue growth factor (CTGF), transforming growth factor beta1 (TGF-ß1), and vascular endothelial growth factor (VEGF) through the AT1R subtype. Blockade of Gαq, not Gαi or Gα12/13, protein signaling inhibited AT1R-mediated upregulation of CTGF, TGF-ß1, and VEGF. In addition, AT1R overstimulation induced upregulation of growth factors via the TGF-ß-dependent and ERK1/2-dependent pathways. Growth factors secreted from cardiac fibroblasts are necessary for the induction of hypertrophic markers, atrial natriuretic peptide (ANP) and ß-myosin heavy chain (ß-MHC), resulting in myocyte hypertrophy. Candesartan, irbesartan, and valsartan had greater effects than losartan for blockade of fibrotic and hypertrophic effects of Ang II. Our data support the concept whereby sustained AT1R stimulation contributes to the development of myocardial fibrosis and hypertrophy, and advances understanding of this complex AT1R signaling, including fibroblasts-myocytes communication during pathological conditions.

Inhibition of LPS-Induced Microglial Activation by the Ethyl Acetate Extract of Pueraria mirifica.

Microglial activation has been found to play a crucial role in various neurological disorders. Proinflammatory substances overproduced by activated microglia, such as cytokines, chemokines, reactive oxygen species, and nitric oxide (NO), can result in neuroinflammation that further exacerbates the course of the diseases. This study aimed to explore the anti-inflammatory effect of the ethyl acetate extract of Pueraria mirifica on microglial activation. Lipopolysaccharide (LPS)-induced inflammation was used as a model to investigate the effects of P. mirifica on HAPI (highly aggressive proliferating immortalized), a rat microglial cell line. Administration of ethyl acetate extract from the tuberous roots of P. mirifica to HAPI cells dose-dependently reduced NO production and iNOS expression induced by LPS. Attenuation of IRF-1 (interferon regulatory factor-1) induction, one of the transcription factors governing iNOS expression, suggested that the inhibitory effect on NO production by the plant extract was at least partially mediated through this transcription factor. In addition, LPS-stimulated mRNA expression of MCP-1 (monocyte chemoattractant protein-1), IL-6 (interleukin-6), and TNF-α (tumor necrosis factor-α) was also suppressed with P. mirifica extract pretreatment. This study indicates that the ethyl acetate extract of P. mirifica could potentially serve as an anti-inflammatory mediator and may be useful in relieving the severity of neurological diseases where microglia play a role.

Plumbagin Suppresses Breast Cancer Progression by Downregulating HIF-1α Expression via a PI3K/Akt/mTOR Independent Pathway under Hypoxic Condition.

Hypoxia-inducible factor-1α (HIF-1α) is a major transcriptional regulator that plays a crucial role in the hypoxic response of rapidly growing tumors. Overexpression of HIF-1α has been associated with breast cancer metastasis and poor clinical prognosis. Plumbagin, the main phytochemical from Plumbago indica, exerts anticancer effects via multiple mechanisms. However, its precise mechanisms on breast cancer cells under hypoxic conditions has never been investigated. This study aims to examine the anticancer effect of plumbagin on MCF-7 cell viability, transcriptional activity, and protein expression of HIF-1α under normoxia and hypoxia-mimicking conditions, as well as reveal the underlying signaling pathways. The results demonstrate that plumbagin decreased MCF-7 cell viability under normoxic conditions, and a greater extent of reduction was observed upon exposure to hypoxic conditions induced by cobalt chloride (CoCl2). Mechanistically, MCF-7 cells upregulated the expression of HIF-1α protein, mRNA, and the VEGF target gene under CoCl2-induced hypoxia, which were abolished by plumbagin treatment. In addition, inhibition of HIF-1α and its downstream targets did not affect the signaling transduction of the PI3K/Akt/mTOR pathway under hypoxic state. This study provides mechanistic insight into the anticancer activity of plumbagin in breast cancer cells under hypoxic conditions by abolishing HIF-1α at transcription and post-translational modifications.

Andrographolide Exhibits Anticancer Activity against Breast Cancer Cells (MCF-7 and MDA-MB-231 Cells) through Suppressing Cell Proliferation and Inducing Cell Apoptosis via Inactivation of ER-α Receptor and PI3K/AKT/mTOR Signaling.

Breast cancer is the most common cancer among women worldwide. Chemotherapy followed by endocrine therapy is the standard treatment strategy after surgery or radiotherapy. However, breast cancer is highly resistant to the treatments leading to the recurrence of breast cancer. As a result, the development of alternative medicines derived from natural plants with fewer side effects is being emphasized. Andrographolide isolated from Andrographis paniculata is one of the potential substances with anti-cancer properties in a variety of cell types, including breast cancer cells. This study aims to investigate the anti-cancer effects of andrographolide in breast cancer cells by evaluating cell viability and apoptosis as well as its underlying mechanisms through estrogen receptor (ER)-dependent and PI3K/AKT/mTOR signaling pathways. Cell viability, cell apoptosis, mRNA or miRNA, and protein expression were examined by MTT assay, Annexin V-FITC, qRT-PCR, and Western blot analysis, respectively. MCF-7 and MDA-MB-231 cell viability was reduced in a concentration- and time-dependent manner after andrographolide treatment. Moreover, andrographolide induced cell apoptosis in both MCF-7 and MDA-MB-231 cells by inhibiting Bcl-2 and enhancing Bax expression at both mRNA and protein levels. In MCF-7 cells, the ER-positive breast cancer, andrographolide showed an inhibitory effect on cell proliferation through downregulation of ERα, PI3K, and mTOR expression levels. Andrographolide also inhibited MDA-MB-231 breast cancer cell proliferation via induction of cell apoptosis. However, the inhibition of MCF-7 and MDA-MB-231 cell proliferation of andrographolide treatment did not disrupt miR-21. Our findings showed that andrographolide possesses an anti-estrogenic effect by suppressing cell proliferation in MCF-7 cells. The effects were comparable to those of the anticancer drug fulvestrant in MCF-7 cells. This study provides new insights into the anti-cancer effect of andrographolide on breast cancer and suggests andrographolide as a potential alternative from the natural plant for treating breast cancer types that are resistant to tamoxifen and fulvestrant.

Flavonoids from Nelumbo nucifera Gaertn., a Medicinal Plant: Uses in Traditional Medicine, Phytochemistry and Pharmacological Activities.

Nelumbo nucifera Gaertn. has been used as an important ingredient for traditional medicines since ancient times, especially in Asian countries. Nowadays, many new or unknown phytochemical compounds from N. nucifera are still being discovered. Most of the current research about pharmacological activity focus on nuciferine, many other alkaloids, phenolic compounds, etc. However, there is no current review emphasizing on flavonoids, which is one of the potent secondary metabolites of this species and its pharmacological activities. Therefore, following a taxonomic description, we aim to illustrate and update the diversity of flavonoid phytochemical compounds from N. nucifera, the comparative analysis of flavonoid compositions and contents in various organs. The uses of this species in traditional medicine and the main pharmacological activities such as antioxidant, anti-inflammatory, anti-diabetic, anti-obesity, anti-angiogenic and anti-cancer activities are also illustrated in this works.

A LC/MS/MS method for determination of tenofovir in human plasma and its application to toxicity monitoring.

Tenofovir disoproxil fumarate is a pro-drug of the active metabolite tenofovir widely used against the HIV1, HIV2, and Hepatitis B virus. Several studies have been conducted and found kidney injury associated with tenofovir exposure. High tenofovir plasma concentration correlated with kidney injury in tenofovir-exposed patients. The present study developed and validated a simple and cost-effective LC/MS/MS method to determine tenofovir level in human plasma. A small plasma volume of 80 µl is utilized for the sample preparation. The samples were separated by Luna C18 (100 mm × 2.0 mm, 3 µm) using gradient elution with a mobile phase consisting of water (containing 0.1% formic acid) and acetonitrile (90:10, v/v). The detection was achieved through multiple reaction monitoring using positive ionization mode on the triple quadrupole mass spectrometer with a run time of 10 min. The monitoring transitions were set at m/z 288.0 → 176.1 and 136.1 for tenofovir and m/z 226.1 → 152.0 for acyclovir (as the internal standard). This standard curve was linear from 10 to 640 ng/ml, with the lower limit of quantification of 10 ng/ml. The inter- and intra-day precision results were less than 12.3% and their accuracies were within the acceptable range of 84.9-113.1%. The validated method was successfully applied to the study of tenofovir induced kidney injury in HIV-1 infected patients taking 300 mg once daily for more than 4 weeks.

Molecular docking based screening of triterpenoids as potential G-quadruplex stabilizing ligands with anti-cancer activity.

Triterpenoids isolated from Ganoderma lucidum (GLTs) exhibit a broad spectrum of anti-cancer properties, including anti-proliferative, anti-metastatic and anti-angiogenic activities. Current research studies revealed the role by GLTs in inducing apoptosis and suppression of telomerase activity of cancer cells with much lower toxicity to healthy cells. Compounds selectively binding and stabilizing G-quadruplex structures could inhibit the telomerase or downregulate the oncogenes and may act as anti-cancer agents. Targeting human telomeric G-quadruplex DNA could be one of the mechanisms by which these GLTs exert anti-cancer activity. In this study, 208 GLTs were screened for ligands with high binding affinity and selectively to stabilize the pG4DNA by using the docking tool AutoDock4. The results showed that ganoderic acid A and ganoderic acid Df exhibit high binding affinity and selectively bind to the lateral groove of pG4DNA. Based on our findings, we suggest that the triterpenoid represents a new class of G-quadruplex groove binding ligands and thus act as potential anti-cancer agents.

Association between butyrylcholinesterase K variant and mild cognitive impairment in the Thai community-dwelling patients.

OBJECTIVE: To study the association of the butyrylcholinesterase K variant (BChE-K) and the plasma BChE activity with mild cognitive impairment (MCI) in Thai community-dwelling patients. METHODS: One hundred patients diagnosed with MCI and 100 control subjects were recruited from the community-dwelling setting in Bangkok, Thailand. The genotype and allele distributions of the BChE-K were determined by polymerase chain reaction and subsequent DNA sequencing. The BChE activity was measured in plasma according to the Ellman's method. RESULTS: The BChE-K allele frequencies in the Thai community-dwelling patients were in accordance with other ethnics. The BChE-K allele frequency in the control subjects (12%) was higher than that of MCI patients (5.5%), suggesting a protective role of BChE-K for MCI in the Thai community-dwelling patients. The BChE-K homozygotes were significantly associated with lower BChE activity. CONCLUSION: Our results suggested that the BChE-K may be implicated as a protective factor for MCI in the Thai community-dwelling patients, although a further study with a large sample size is warranted to confirm this.

Pharmacogenomic Study Reveals New Variants of Drug Metabolizing Enzyme and Transporter Genes Associated with Steady-State Plasma Concentrations of Risperidone and 9-Hydroxyrisperidone in Thai Autism Spectrum Disorder Patients.

The present study sought to investigate the genetic variants in drug metabolizing enzyme and transporter (DMET) genes associated with steady-state plasma concentrations of risperidone among Thai autism spectrum disorder (ASD) patients. ASD patients taking risperidone for at least 1 month were enrolled for this pharmacogenomic study. Genotyping profile was obtained using Affymetrix DMET Plus array interrogating 1931 variants in 231 genes. Steady-state plasma risperidone and 9-hydroxyrisperidone were measured using liquid chromatography/tandem mass spectrometry assay. The final analysis included 483 markers for 167 genes. Six variants, ABCB11 (c.3084A > G, c.∗420A > G, c.∗368G > A, and c.∗236G > A) and ADH7 (c.690G > A and c.-5360G > A), were found to be associated with plasma concentrations of risperidone. 9-Hydroxyrisperidone and the total active-moiety levels were associated with six gene variants, SCLO1B1 (c.-11187G > A and c.521T > C), SLCO1B3 (c.334G > T, c.699A > G, and c.1557G > A), and SLC7A5 c.∗438C > G. Polymorphisms in UGT2B4 c.∗448A > G and CYP2D6 (c.1661G > C, c.4180G > C, and c.-2178G > A) showed considerable but not significant associations with metabolic ratio. This pharmacogenomic study identifies new genetic variants of DMET genes in monitoring risperidone therapy.

Clinically relevant genetic variants of drug-metabolizing enzyme and transporter genes detected in Thai children and adolescents with autism spectrum disorder.

Single-nucleotide polymorphisms (SNPs) among drug-metabolizing enzymes and transporters (DMETs) influence the pharmacokinetic profile of drugs and exhibit intra- and interethnic variations in drug response in terms of efficacy and safety profile. The main objective of this study was to assess the frequency of allelic variants of drug absorption, distribution, metabolism, and elimination-related genes in Thai children and adolescents with autism spectrum disorder. Blood samples were drawn from 119 patients, and DNA was extracted. Genotyping was performed using the DMET Plus microarray platform. The allele frequencies of the DMET markers were generated using the DMET Console software. Thereafter, the genetic variations of significant DMET genes were assessed. The frequencies of SNPs across the genes coding for DMETs were determined. After filtering the SNPs, 489 of the 1,931 SNPs passed quality control. Many clinically relevant SNPs, including CYP2C19*2, CYP2D6*10, CYP3A5*3, and SLCO1B1*5, were found to have frequencies similar to those in the Chinese population. These data are important for further research to investigate the interpatient variability in pharmacokinetics and pharmacodynamics of drugs in clinical practice.

ABCB1 and ABCC2 and the risk of distant metastasis in Thai breast cancer patients treated with tamoxifen.

BACKGROUND: Genetic polymorphisms of drug-metabolizing enzymes and transporters have been extensively studied with regard to tamoxifen treatment outcomes. However, the results are inconclusive. Analysis of organ-specific metastasis may reveal the association of these pharmacogenetic factors. The aim of this study is to investigate the impact of CYP3A5, CYP2D6, ABCB1, and ABCC2 polymorphisms on the risk of all distant and organ-specific metastases in Thai patients who received tamoxifen adjuvant therapy. METHODS: Genomic DNA was extracted from blood samples of 73 patients with breast cancer who received tamoxifen adjuvant therapy. CYP3A5 (6986A>G), CYP2D6 (100C>T), ABCB1 (3435C>T), and ABCC2 (-24C>T) were genotyped using allelic discrimination real-time polymerase chain reaction assays. The impacts of prognostic clinical factors and genetic variants on disease-free survival were analyzed using the Kaplan-Meier method and Cox regression analysis. RESULTS: In the univariate analysis, primary tumor size >5 cm was significantly associated with increased risk of distant metastasis (P=0.004; hazard ratio [HR] =3.05; 95% confidence interval [CI], 1.44-6.47). In the multivariate analysis, tumor size >5 cm remained predictive of distant metastasis (P<0.001; HR=5.49; 95% CI, 2.30-13.10). ABCC2 -24CC were shown to be associated with increased risk of distant metastasis (P=0.040; adjusted HR=2.34; 95% CI, 1.04-5.27). The combined genotype of ABCC2 -24CC - ABCB1 3435 CT+TT was associated with increased risk of distant and bone metastasis (P=0.020; adjusted HR=2.46; 95% CI, 1.15-5.26 and P=0.040; adjusted HR=3.70; 95% CI, 1.06-12.89, respectively). CONCLUSION: This study indicates that polymorphisms of ABCC2 and ABCB1 are independently associated with bone metastasis. Further prospective studies with larger sample sizes are needed to verify this finding.

Sustained ßAR Stimulation Mediates Cardiac Insulin Resistance in a PKA-Dependent Manner.

Insulin resistance is a condition in which cells are defective in response to the actions of insulin in tissue glucose uptake. Overstimulation of ß-adrenergic receptors (ßARs) leads to the development of heart failure and is associated with the pathogenesis of insulin resistance in the heart. However, the mechanisms by which sustained ßAR stimulation affects insulin resistance in the heart are incompletely understood. In this study, we demonstrate that sustained ßAR stimulation resulted in the inhibition of insulin-induced glucose uptake, and a reduction of insulin induced glucose transporter (GLUT)4 expression that were mediated by the ß2AR subtype in cardiomyocytes and heart tissue. Overstimulation of ß2AR inhibited the insulin-induced translocation of GLUT4 to the plasma membrane of cardiomyocytes. Additionally, ßAR mediated cardiac insulin resistance by reducing glucose uptake and GLUT4 expression via the cAMP-dependent and protein kinase A-dependent pathways. Treatment with ß-blockers, including propranolol and metoprolol antagonized isoproterenol-mediated insulin resistance in the heart. The data in this present study confirm a critical role for protein kinase A in ßAR-mediated insulin resistance.

Association of CYP3A4/5, ABCB1 and ABCC2 polymorphisms and clinical outcomes of Thai breast cancer patients treated with tamoxifen.

BACKGROUND: Pharmacogenetic study of cytochrome P450 (CYP) gene CYP2D6 and tamoxifen outcomes remain controversial. Apart from CYP2D6, other drug-metabolizing enzymes and transporters also play a role in tamoxifen metabolic pathways. The aim of this study is to investigate the impact of CYP3A4/5, ABCB1, and ABCC2 polymorphisms on the risk of recurrence in Thai patients who received tamoxifen adjuvant therapy. METHODS: Patients with early-stage breast cancer who received tamoxifen adjuvant therapy were recruited in this study. All six single-nucleotide polymorphisms (SNPs), including CYP3A4*1B (-392 A>G)/*18(878 T>C), CYP3A5*3(6986 G>A), ABCB1 3435 C>T, ABCC2*1C(-24 C>T), and ABCC2 68231 A>G, were genotyped using real-time polymerase chain reaction assays. The impacts of genetic variants on disease-free survival (DFS) were analyzed using the Kaplan-Meier method and Cox regression analysis. RESULTS: The ABCB1 3435 C>T was found to have the highest allele frequency among other variants; however, CYP3A4*1B/*18 could not be found in this study. Patients with heterozygous ABCB1 3435 CT genotype showed significantly shorter DFS than those with homozygous 3435 CC genotype (P = 0.041). In contrast, patients who carried homozygous 3435 TT genotype showed no difference in DFS from wild-type 3435 CC patients. Cox regression analysis showed that the relative risk of recurrence was increased by five times (P = 0.043; hazard ratio = 5.11; 95% confidence interval: 1.05-24.74) in those patients carrying ABCB1 3435 CT genotype compared to those with ABCB1 3435 CC. CONCLUSION: ABCB1 3435 C>T is likely to have a clinically significant impact on recurrence risk in Thai patients with breast cancer who receive tamoxifen adjuvant therapy.

Blockade of the renin-angiotensin system with delphinidin, cyanin, and quercetin.

Overactivation of the renin-angiotensin system is one of the most important risk factors for the development of hypertension. The use of the crude extracts and/or active compounds, such as anthocyanins and quercetin, of herbal plants that have antihypertensive effects is beneficial for decreasing of blood pressure level. However, the molecular mechanisms by which anthocyanins (delphinidin and cyanin) and quercetin regulate the renin-angiotensin system are not completely understood. In this study, we demonstrate that delphinidin, cyanin, and quercetin interrupt the renin-angiotensin system signaling pathway by inhibiting the angiotensin-converting enzyme activity and decreasing its mRNA production. Furthermore, treatment with either delphinidin or cyanin significantly inhibited renin mRNA production. However, delphinidin, cyanin, and quercetin did not act as the angiotensin II type 1 receptor antagonist and did not play roles in the regulation of its internalization. The direct inhibition of components of the renin-angiotensin system advances our understanding of the antihypertensive effects of these compounds.

The effects of imidazoline agents on the aggregation of human platelets.

Clonidine (2-[(2,6-dichlorophenyl)amino]-2-imidazoline), an imidazoline alpha(2)-adrenoceptor agonist, is known to exert complex effects on human platelet aggregation distinct from those of the catecholamines, which are non-imidazoline alpha-adrenoceptor agonists. This study has investigated the aggregatory/anti-aggregatory effects of various imidazolines on human platelets. Blood samples were taken from normal volunteers and platelet aggregation was assessed by a turbidimetric method using a Chronolog aggregometer. Noradrenaline (2 microM) and adenosine diphosphate (1 microM) were used as aggregating agents. The results showed that, with the exception of moxonidine, all of the imidazoline agents used (with or without alpha(2)-adrenoceptor activity) were able to inhibit noradrenaline-induced platelet aggregation. Compared with the non-imidazoline alpha(2)-adrenergic antagonist, yohimbine, the rank order of potency was: efaroxan (IC50 = 3.07 x 10(-8) M) > idazoxan (IC50 = 1.74 x 10(-7) M) > tolazoline (IC50 = 3.90 x 10(-7) M) > clonidine (IC50 = 1.49 x 10(-6) M) congruent with antazoline (IC50 = 1.77 x 10(-6) M) > yohimbine (IC50 = 3.19 x 10(-6) M) > rilmenidine (IC50 = 1.27 x 10(-5) M) > moxonidine (IC50 > 10(-4) M). Clonidine-displacing substance (CDS), a putative endogenous ligand at imidazoline receptors, was found to inhibit noradrenaline-induced platelet aggregation. Harmane, norharmane and agmatine, putative candidates for the active principle of CDS, had no effect on noradrenaline-induced platelet aggregation. In contrast to noradrenaline-induced aggregation, ADP-induced platelet aggregation was neither potentiated nor inhibited by the imidazoline agents, with the exceptions of clonidine and moxonidine. In conclusion, most imidazoline agents effectively inhibit noradrenaline-induced human platelet aggregation. The lack of effect of moxonidine and the proposed endogenous ligands suggested this effect was mediated by an 'atypical' non-adrenoceptor imidazoline-binding site. The results indicated an anti-aggregatory role of imidazoline compounds on noradrenaline-induced human platelet aggregation. In addition, CDS might be an endogenous modulator that prevented platelet hyper-reactivity to catecholamine stimulation.