α-Glucosidase inhibition of prenylated pyranocoumarins: Kinetics, in silico prediction of their physicochemical properties and molecular docking.

Three naturally occurring prenylated pyranocoumarins, nordentatin (1), dentatin (2), and clausarin (3), isolated from the roots of Clausena excavata (Family Rutaceae), and O-methylclausarin (4) which was obtained by methylation of 3, were investigated for their α-glucosidase inhibitory activity. The mechanism of action and the in silico prediction of their physicochemical and ADMET properties as well as the molecular docking were also studied. Compounds 1-4 exhibited stronger α-glucosidase inhibitory activity than the positive control, acarbose, through a non-competitive mechanism. Among them, 3 exhibited the highest activity, with an IC50 of 8.36 µM, which is significantly stronger than that of acarbose (IC50 = 430.35 µM). The prenyl group on C-3 and the hydroxyl group on C-5 in 3 may play important roles in enhancing the activity. Calculated physicochemical and ADMET parameters of 1-4 satisfied the Lipinski's and Veber's rules. Molecular simulation analysis indicated they are promising drug candidates with no hepatotoxicity. Compound 3 exhibited potent activity in the experiment and demonstrated good drug properties based on the calculations. A molecular docking study revealed that 3 showed H-bonding and π-π stacking interactions with selective Phe321, as well as interactions with thirteen other amino acid residues of the α-glucosidase.

Dipterocarpol in Oleoresin of Dipterocarpus alatus Attributed to Cytotoxicity and Apoptosis-Inducing Effect.

Dipterocarpus alatus Roxb. ex G. Don is widely found in Southeast Asia. Its oleo-resin has reportedly been used in biodiesel production. Two different biodiesel production processes produce resinous byproducts, namely degumming (DG) and distillation (DT). Gas chromatography-mass spectrometry identified sesquiterpenes and triterpenes in oleo-resin, DG, and DT; and long-chain hydrocarbons in oleo-resin. High-performance liquid chromatography detected dipterocarpol as a marker compound, with the highest to lowest amounts detected in DG, DT, and oleo-resin, respectively. Oleo-resin, DG, and DT exerted more cytotoxicity than dipterocarpol, and melphalan, a chemotherapeutic drug. Oleo-resin, DG, and DT exerted cytotoxicity to a different degree in T cell leukemia (Jurkat), cervical adenocarcinoma (HeLa), and human hepatocellular carcinoma (HepG2) cells, while the highest selectivity was found in the Jurkat cells compared to the non-cancer Vero cells. Dipterocarpol exhibited the highest cytotoxicity in HepG2 cells and the lowest cytotoxicity in Jurkat cells. Oleo-resin, DG, and DT induced apoptosis in Jurkat cells. In oleo-resin, DG, and DT, dipterocarpol and other compounds may act in synergy leading to cytotoxicity and an apoptosis-inducing effect. Oleo-resin, DG, and DT could be potential sources for anticancer agents. Dipterocarpol could serve as a biomarker for follow ups on the anticancer activity of a sample from D. alatus.

Impact of Tea Processing on Tryptophan, Melatonin, Phenolic and Flavonoid Contents in Mulberry (Morus alba L.) Leaves: Quantitative Analysis by LC-MS/MS.

Mulberry (Morus alba L.) leaves from two cultivars, Yai-Burirum (YB) and Khunphai (KP), were prepared into green tea (GT) and black tea (BT). Compared to fresh leaf (FL) extract, GT and BT extracts were evaluated for their total phenolic and total flavonoid contents. Total phenolic content (TPCs) in all samples ranged between 129.93 and 390.89 mg GAE/g extract. The processing of tea decreased the levels of TPC when compared to FL extracts in both cultivars. The total flavonoid content (TFCs) in all samples was found in the range of 10.15-39.09 mg QE/g extract and TFCs in GT and BT extracts were higher than FL extracts. The change in tryptophan, melatonin, phenolic and flavonoid contents was investigated by liquid chromatography-mass spectroscopy (LC-MS). The results exhibited that tryptophan contents in all samples were detected in the range 29.54-673.72 µg/g extract. Both GT and BT extracts increased tryptophan content compared to FL extracts. BT extracts presented the highest amounts of tryptophan among others in both cultivars. Phenolic compounds were found in mulberry leaf extracts, including gallic acid, caffeic acid, gentisic acid, protocatechuic acid and chlorogenic acid. Chlorogenic acid presented the highest amount in all samples. Almost all phenolic acids were increased in the processed tea extracts except chlorogenic acid. Rutin was the only flavonoid that was detected in all extracts in the range 109.48-1009.75 mg/g extract. The change in phenolic and flavonoid compounds during tea processing resulted in the change in antioxidant capacities of the GT and BT extracts. All extracts presented acetylcholinesterase enzyme (AChE) inhibitory activity with IC50 in the range 146.53-165.24 µg/mL. The processing of tea slightly increased the AChE inhibitory effect of GT and BT extracts. In conclusion, processed tea from mulberry leaves could serve as a new alternative functional food for health-concerned consumers because it could be a promising source of tryptophan, phenolics and flavonoids. Moreover, the tea extracts also had antioxidative and anti-AChE activities.

Anthocyanin complex niosome gel accelerates oral wound healing: In vitro and clinical studies.

An anthocyanin complex (AC), composed of extracts of purple waxy corn and blue butterfly pea petals, and AC niosomes, bilayered vesicles of non-ionic surfactants, were compared in in vitro and clinical studies. Cultured fibroblasts subjected to a scratch wound were monitored for cell viability, cell migration, nuclear morphology and protein expression. Scratched cells showed accelerated wound healing activity, returning to normal 24 h after treatment with AC niosomes (0.002 mg/mL). Western blots and immunocytochemistry indicated upregulation of type I, III and IV collagens, fibronectin and laminins in AC niosome-treated scratched cells. A randomized block placebo-controlled double-blind clinical trial in 60 volunteers (18-60 years old) with oral wounds indicated that AC niosome gel accelerated wound closure, reduced pain due to the oral wounds and improved participants' quality of life more than AC gel, triamcinolone gel and placebo gel. These data are consistent with enhanced delivery of AC to fibroblasts by use of niosomes. AC niosomes activated fibroblasts within wounded regions and accelerated wound healing, indicating that AC niosomes have therapeutic potential.

Chemical Composition, Antioxidant and Cytotoxicity Activities of Leaves, Bark, Twigs and Oleo-Resin of Dipterocarpus alatus.

Dipterocarpus alatus (Dipterocarpaceae) is a medicinal plant whose use is well known for the treatment of genito-urinary diseases. However, there is no report of its cytotoxic potential. In this study, the chemical composition, antioxidant and cytotoxic activities of extracts of the leaves, bark, twigs and oleo-resin from D. alatus are investigated. Cytotoxicity was measured by the neutral red (NR) assay against HCT116, SKLU1, SK-MEL2, SiHa and U937 cancer cell lines and antioxidant capacity was evaluated by DPPH, ABTS radical scavenging, and ferric reducing antioxidant power (FRAP) assays. The chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). Leaf, bark and twig extracts exhibited stronger antioxidant activity than oleo-resin, with bark extract showing the highest antioxidant activity and the highest total phenolic content. All samples showed more cytotoxic activity against the U937 cell line than HCT116, SKLU1, SK-MEL2 and SiHa cells with oleo-resin being more cytotoxic than melphalan against U937 cells. Chemical composition analysis of oleo-resin by GC-MS showed that the major components were sesquiterpenes, namely α-gurjunene (30.31%), (-)-isoledene (13.69%), alloaromadendrene (3.28%), ß-caryophyllene (3.14%), γ-gurjunene (3.14%) and spathulenol (1.11%). The cytotoxic activity of oleo-resin can be attributed to the sesquiterpene content, whereas the cytotoxic and antioxidant activities of leaf, bark and twig extracts correlated to total phenolic content.

Total flavonoids, total phenolics, 1-deoxynojirimycin content and alpha-glucosidase inhibitory activity of Thai silkworm races (Bombyx mori Linn.).

The silkworm powder (Bombyx mori Linn.) from Japanese and Korean races has well known used as a blood glucose lowering substance. However, the study of bioactive compounds and hypoglycemic effect on Thai silkworm races is still limited. This study was aimed to investigate the flavonoid, phenolic and 1-deoxynojirimycin (DNJ) contents, and α-glucosidase inhibitory activity of three Thai silkworm races (Nanglai, Nangnoi and Samrong) of the 5th instar, 2nd 4th day silkworm powders. The total flavonoid, phenolic contents and α-glucosidase inhibitory activity were performed using spectrophotometric methods. The DNJ content was determined using derivatization and further analyzed by HPLC. Nangnoi showed the highest flavonoid content with 12.32±0.41mg quercetin equivalent/g silkworm powder. Nanglai showed the highest phenolic content with 78.74±1.43mg gallic acid equivalent/g silkworm powder. Regarding DNJ content, Nangnoi expressed the highest at 3.11±0.01mg/g silkworm powder. According to the age of silkworm, powders of the instar 5th, day 3rd were provided the highest α-glucosidase inhibitory activity (p<0.05). This study clearly indicated that the 5th instar, 3rd day of Thai silkworms exhibited the highest flavonoid, phenolic, DNJ contents and α-glucosidase inhibitory activity. Further study on blood glucose lowering activity should be performed.

Pharmacological effects of Chatuphalatika in hyperuricemia of gout.

CONTEXT: Chatuphalatika (CTPT), is a Thai herbal formulation mixture of Phyllanthus emblica Linn. (Euphorbiaceae), Terminalia belerica Linn. (Combretaceae), T. chebula and the fruit of T. arjuna (Roxb.) Wight & Arn. CTPT is considered to exert anti-inflammatory and antihyperuricemic effects, but there have been no reports to demonstrate these pharmacological effects in a quantitative manner. OBJECTIVES: To investigate the antioxidative, anti-inflammatory and antihyperuricemic effects of CTPT. MATERIALS AND METHODS: Antioxidant activities of CTPT extracts were measured in vitro by DPPH, ABTS and FRAP assays, and anti-inflammatory effect by measuring inflammatory mediator production induced by lipopolysaccharide (LPS) in RAW264.7 macrophages. The mechanism of the hypouricemic effect was investigated using oxonate-induced hyperuricemic ddY mice treated with oral administrations of CTPT at 250, 500 and 1000 mg/kg. RESULTS: Antioxidant activities of CTPT measured by ABTS and FRAP assays were 1.35 g TEAC/g extract and 10.3 mmol/100 g extract, respectively. IC50 for the inhibition of DPPH radical was 13.8 µg/mL. CTPT (10 µg/mL) significantly downregulated the mRNA expression of TNF-α and iNOS in RAW 264.7 cells. Lineweaver-Burk analysis of the enzyme kinetics showed that CTPT inhibited xanthine oxidase (XOD) activity in a noncompetitive manner with the Ki of 576.9 µg/mL. Oral administration of CTPT (1000 mg/kg) significantly suppressed uric acid production by inhibiting hepatic XOD activity, and decreased plasma uric acid levels in hyperuricemic mice by approximately 40% (p < 0.05). CONCLUSIONS: This study demonstrated for the first time the antioxidative, anti-inflammatory and antihyperuricemic effects of CTPT in vivo and in vitro, suggesting a possibility of using CTPT for the treatment of hyperuricemia in gout.

A meta-analysis of efficacy of Morus alba Linn. to improve blood glucose and lipid profile.

PURPOSE: The previous studies have reported the Morus alba may improve blood glucose and lipid profile. The evidence from these studies is not consistent. This meta-analysis was to evaluate efficacy of products derived from M. alba on blood glucose and lipid levels. METHODS: Literature was reviewed via international database (PubMed, PubMed Central, ScienceDirect, and SciSearch) and Thai databases. Thirteen RCTs with high quality, assessed by Jadad score, were included. RESULTS: M. alba expressed a significant reduction in postprandial glucose (PPG) at 30 min (MD -1.04, 95 % CI -1.36, -0.73), 60 min (MD -0.87, 95 % CI -1.27, -0.48) and 90 min (MD -0.55, 95 % CI -0.87, -0.22). The difference was not found in the levels of other glycaemic (FBS, HbA1C, or HOMA-IR) and lipidaemic (TC, TG, LDL, or HDL) markers. Serious adverse effects were found neither in the control nor in the group received M. alba. CONCLUSION: Products derived from M. alba can effectively contribute to the reduction in PPG levels, but large-scale RCTs would be informative.

Efficacy of Varenicline in the Treatment of Alcohol Dependence: An Updated Meta-Analysis and Meta-Regression.

BACKGROUND: Although varenicline has been used for alcohol dependence (AD) treatment, its efficacy for this condition remains controversial. AIMS: This systematic review and meta-analysis of randomized controlled trials (RCTs) assesses the efficacy and safety of varenicline in patients with AD. METHODS: PubMed, Cochrane Library, ScienceDirect, Web of Science, and ThaiLis were systematically searched. RCTs investigating the efficacy and safety of varenicline in patients with AD were included. Study selection, data extraction, and quality assessment were independently performed by two authors. The Jadad score and Cochrane risk of bias were used to assess the quality of the included studies. Heterogeneity was assessed using I2 and chi-squared tests. RESULTS: Twenty-two high-quality RCTs on 1421 participants were included. Varenicline significantly reduced alcohol-related outcomes compared with placebo based on percentage of abstinent days (standardized mean difference [SMD] 4.20 days; 95% confidence interval [CI]: 0.21, 8.19; p = 0.04), drinks per day (SMD -0.23 drinks; 95% CI: -0.43, -0.04; p = 0.02), drinks per drinking day (SMD -0.24 drinks; 95% CI: -0.44, -0.05; p = 0.01), craving assessed using the Penn alcohol craving scale (SMD -0.35; 95% CI: -0.59, -0.12; p = 0.003), and craving assessed using the alcohol urge questionnaire (SMD -1.41; 95% CI: -2.12, -0.71; p < 0.0001). However, there were no significant effects on abstinence rate, percentage of drinking days, percentage of heavy drinking days, alcohol intoxication, or drug compliance. Serious side effects were not observed in the varenicline or placebo groups. CONCLUSION: Our results indicated that AD patients treated with varenicline showed improvement in percentage of very heavy drinking days, percentage of abstinent days, drinks per day, drinks per drinking day, and craving. However, well-designed RCTs with a large sample size and long duration on varenicline treatment in AD remain warranted to confirm our findings.

Effect of Germination and Illumination on Melatonin and Its Metabolites, Phenolic Content, and Antioxidant Activity in Mung Bean Sprouts.

Mung bean (Vigna radiata L.) sprouts are increasingly consumed and have become part of a healthy diet. The sprouts are composed of proteins, carbohydrates, and biochemical compounds. During germination, the phytochemical compounds are significantly elevated, especially under stress conditions such as salinity, drought, extreme temperature, and illumination. The present study examined the effects of light and germination time on the bioactive compounds in mung bean sprout extracts. Mung bean seeds were sprouted under different light exposure conditions, and the phytochemical composition and antioxidant activity of sprout extracts were determined compared to seeds. The results show that tryptophan sharply decreased during germination. On the contrary, melatonin, polyphenols, and total phenolic content (TPC) were elevated with increased germination time, correlated with increased antioxidant activity. Sprouts germinated in the dark presented higher levels of melatonin and TPC compared with those germinated under 12 h light exposure (3.6- and 1.5-fold, respectively). In conclusion, germination can enhance valuable phytochemicals and antioxidant activity of mung bean sprouts. Mung bean sprouts may be a good alternative functional food for promoting human health.

Pharmacy students' preparation to provide pharmaceutical care for patients with non-communicable diseases in six ASEAN countries: A qualitative study.

INTRODUCTION: Pharmacy education programs prepare graduates to promote health for patients with noncommunicable disease (NCDs), but there is limited information concerning Association of South East Asia Nations (ASEAN) countries. The study aim was to synthesize academic staff's, alumni's, and alumni supervisors' perspectives on preparation for students to provide pharmaceutical care in NCDs. METHODS: A qualitative research design was used. In-depth interviews with structured questions following the Context, Input, Process, and Product/Outcomes model framework were conducted with four academic staff, three alumni, and three alumni supervisors from six study sites in six countries. Interview questions were constructed in Thai and translated to English by using forward and backward translation. Verbatim transcriptions were used to perform thematic analysis with investigator triangulation. RESULTS: Sixty participants were included. The context showed three main themes related to Burden of NCDs, Pharmacist Roles in NCDs, and Goals. The input showed three main themes of Teaching Methods, Development Plans for Academic Staff, and Budgets and Infrastructure. The process showed one main theme of Struggles in Teaching Methods. The outcomes/outputs showed three main themes of Individual, Organizational, and Professional Levels. Schools need curricula that focus on NCDs, pharmacist competency and skills, and academic preparation of students for practice. Gaps limiting achievement of goals included lack of well-trained academic staff, limited learning facilities, self-learning opportunities, acceptance from other health professionals, and career ladders. CONCLUSIONS: The preparation of pharmacy students varied in six ASEAN countries. Pharmacy education programs must address existing gaps that limit achievement of goals related to NCDs.

Effects of Triphala on Lipid and Glucose Profiles and Anthropometric Parameters: A Systematic Review.

AIM: The efficacy of triphala on lipid profile, blood glucose and anthropometric parameters and its safety were assessed. METHODS: Databases such as PubMed, ScienceDirect, Web of Science, and Thai Library Integrated System (ThaiLIS) were systematically searched to review current evidence of randomized controlled trials (RCT) on triphala. RCTs investigating the safety and efficacy of triphala on lipid profile, blood glucose and anthropometric parameters were included. Study selection, data extraction, and quality assessment were performed independently by 2 authors. RESULTS: Twelve studies on a total of 749 patients were included. The triphala-treated groups showed significantly reduced low-density lipoprotein-cholesterol, total cholesterol and triglyceride in 6 studies. Five RCTs demonstrated triphala-treated groups led to statistically significant decrease in body weight, body mass index and waist circumference of obese patients. Moreover, triphala significantly decreased fasting blood glucose level in diabetic patients but not in people without diabetes. No serious adverse event associated with triphala was reported during treatment. CONCLUSIONS: This review summarized a current evidence to show triphala might improve the lipid profile, blood glucose, the body weight, body mass index and waist circumference under certain conditions. However, large well-designed RCTs are required to confirm this conclusion.

CE assay for simultaneous determination of charged and neutral impurities in dexamphetamine sulfate using a dual CD system.

A CE assay for the simultaneous determination of charged and uncharged potential impurities (1S,2S-(+)-norpseudoephedrine, 1R,2S-(-)-norephedrine, phenylacetone and phenylacetone oxime) of dexamphetamine sulfate including the stereoisomer levoamphetamine was developed and validated. The optimized background electrolyte consisted of a 50 mM sodium phosphate buffer, pH 3.0, containing 80 mg/mL sulfobutylether-beta-CD and 25 mg/mL sulfated beta-CD. Separations were performed in 40.2/35 cm, 50 mum id fused-silica capillaries at a temperature of 20 degrees C and an applied voltage of -10 kV. 1R,2S-(-)-ephedrine was used as internal standard. The assay was validated in the range of 0.05-1.0% for the related substances and in the range of 0.05-5.0% for levoamphetamine. The LOD was 0.01-0.02% depending on the analyte. The assay also allowed the separation of the E,Z-stereoisomers of phenylacetone oxime. The effect of the degree of substitution of sulfobutylether-beta-CD was investigated. In commercial samples of dexamphetamine sulfate between 3.2 and 3.7% of levoamphetamine were found. Furthermore, phenylacetone and phenylacetone oxime could be observed at the LOD, indicating the synthetic origin of the investigated samples.

CE-MS characterization of negatively charged alpha-, beta- and gamma-CD derivatives and their application to the separation of dipeptide and tripeptide enantiomers by CE.

Sulfated, sulfopropyl and carboxymethyl alpha-, beta- and gamma-CDs were characterized by CE-ESI-MS using an acidic BGE with anodic MS detection and a basic BGE with cathodic MS detection. Isomers of the sulfated CDs comigrated in both systems. The acidic BGE with anodic MS detection resulted in slightly better separation of the isomers of the sulfopropyl CDs, which were separated according to the number of substituents. In the case of carboxymethyl CDs, isomers with an identical number of substituents but with a different substitution pattern with regard to substitution of the primary and secondary hydroxyl groups of the CDs could be separated using the basic BGE. The separation of the LL and DD enantiomers of dipeptides and tripeptides using the CDs was studied with regard to the amino acid sequence and the nature of the CDs. Standardized conditions with regard to buffer pH, CD concentration and voltage were applied. The peptides were analyzed at pH 2.5 as positively charged compounds and at pH 5.3 as neutral zwitterions. The beta-CD derivatives were more effective chiral selectors for the investigated peptides followed by the alpha-CD derivatives. The gamma-CDs were the least effective selectors. The enantiomer migration order depended on both the CD and the amino acid sequence of the peptides. For several combinations, pH-dependent reversal of the enantiomer migration order was also observed.

Investigation of the pH-dependent complex formation between beta-cyclodextrin and dipeptide enantiomers by capillary electrophoresis and calorimetry.

The effect of pH on complex formation between beta-CD and the enantiomers of the dipeptides Ala-Phe, Ala-Tyr and Asp-PheOMe was investigated at 298.15 K by CE and calorimetry. Beta-CD displayed a higher enantioselectivity toward the protonated peptides compared to their zwitterionic forms. While stronger binding of the DD-enantiomers than the LL-stereoisomers were found by calorimetry regardless of the ionization state of the peptides, essentially equal complexation constants of the enantiomers were determined by CE for the zwitterionic species of the peptides. The reversal of the enantiomer migration order observed in CE was attributed primarily to a stereoselective complexation-induced pK(a) shift. In calorimetry, complexation of the protonated DD-enantiomers by beta-CD was accompanied by higher enthalpy and entropy changes resulting in more stable complexes compared to the LL-peptides. The enthalpy and entropy of complexation was affected by pH and peptide structure.

Efficacy of red yeast rice extract on myocardial infarction patients with borderline hypercholesterolemia: A meta-analysis of randomized controlled trials.

Red yeast rice (RYR) extract is widely used for improving cardiovascular outcomes and lipid profiles. However, RYR efficacy on cardiovascular outcomes in myocardial infarction (MI) patients remains unclear. This meta-analysis assessed efficacy of RYR extract in MI patients with borderline hypercholesterolemia. PubMed, CENTRAL, CINAHL, Scopus, Web of Science, and Clinicaltrials.gov were systematically searched from inception through May 2019 for relevant publications. Seven studies with 10,699 MI patients diagnosed with borderline hypercholesterolemia were included. Follow-up periods ranged from 4 weeks - 4.5 years and the studies were overall of high quality with low risk of bias. RYR extract (1,200 mg/day) reduced nonfatal MI (risk ratio (RR) = 0.42, 95% CI 0.34 to 0.52), revascularization (RR = 0.58, 95% CI 0.48 to 0.71), and sudden death (RR = 0.71, 95% CI 0.53 to 0.94). RYR extract also lowered LDL (weighted mean difference (WMD) = -20.70 mg/dL, 95% CI -24.51 to -16.90), TC (WMD = -26.61 mg/dL, 95% CI -31.65 to -21.58), TG (WMD = - 24.69 mg/dL, 95% CI -34.36 to -15.03), and increased HDL levels (WMD = 2.71 mg/dL, 95% CI 1.24 to 4.17). This meta-analysis indicated that RYR extract in MI patients with borderline hypercholesterolemia is associated with improved cardiovascular outcomes and lipid profiles.

A sustainable solution for removal of glutaraldehyde in saline water with visible light photocatalysis.

Glutaraldehyde (GA) is the most common biocide used in unconventional oil and gas production. Photocatalytic degradation of GA in brine simulating oil and gas produced water using Ag/AgCl/BiOCl composite as a photocatalyst with visible light was investigated. Removal of GA at 0.1 mM in 200 g/L NaCl solution at pH 7 was 90% after 75 min irradiation using 5 g/L of the photocatalyst. The GA removal followed pseudo-first order reaction with a rate constant of 0.0303 min-1. At pH 5 or at 300 g/L NaCl, the photocatalytic removal of GA was almost completely inhibited. Similar inhibitions were observed when adding dissolved organic carbon (from humic acid) at 10 and 200 mg/L, or Br- at 120 mg/L to the system. The removal rate of GA markedly increased with increasing pH (5-9), photocatalyst loading (2-8 g/L) and under 350 nm UV (compared to visible light). On the contrary, the removal rate of GA markedly decreased with increasing NaCl and initial GA concentrations (0-300 g/L for NaCl and 0.1-0.4 mM for GA). A quenching experiment was also conducted; electron holes (h+) and superoxide () were found as the main reactive species responsible for the removal of GA while OH had a very limited effect.

Development and validation of a capillary electrophoresis method for the simultaneous determination of impurities of escitalopram including the R-enantiomer.

A stereospecific capillary electrophoresis assay for the simultaneous determination of related substances and the enantiomeric purity of escitalopram was developed by a central composite face-centered factorial design and subsequently validated. Separations were carried out in a 50 microm, 47/40 cm fused-silica capillary. The optimized conditions included 20mM phosphate buffer, pH 2.5, containing 0.5mg/ml beta-cyclodextrin and 22 mg/ml sulfated beta-cyclodextrin as background electrolyte, an applied voltage of -20 kV and a temperature of 28 degrees C. Salicylic acid was used as internal standard. The assay was validated for the (R)-enantiomer of citalopram and the enantiomers of the impurity citadiol in the range of 2.5-150 microg/ml and 2.5-50 microg/ml, respectively. The limit of detection was 0.02% for all compounds, the limit of quantitation 0.05%, relative to a concentration of escitalopram of 5mg/ml. Intraday precision of migration time and peak area ratio were in the range of 0.17-0.44% and 1.64% and 6.25%, respectively. Relative standard deviations of interday precision ranged between 0.84% and 1.85% in the case of migration times and between 5.20% and 9.28% for peak area ratio. The assay was applied to the determination of the purity of escitalopram in bulk drug and tablets. (R)-Citalopram and (S)-citadiol were detected as impurities.

Hypoglycemic and Antioxidant Activities of the Water Extract of Aquilaria crassna Leaves in Streptozotocin-Nicotinamide-Induced Type-2 Diabetic Mice.

Antidiabetic effect of the water extract of Aquilaria crassna (A. crassna) leaves was recently claimed by some diabetic patients in Thailand, whereas its experimental evidence has not been published yet. The present study was therefore conducted to investigate pharmacological activities of the water extract of A. crassna leaves, focusing on its antioxidative and hypoglycemic effects in vitro and in vivo using streptozotocin (STZ)-nicotinamide (NA)-induced type 2 diabetic (DM) mice. An antioxidant activity of the herb extract was confirmed using a 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical scavenging assay, and its IC50 on DPPH inhibition was determined to be 34.6 µg/mL. The extract also inhibited α-glucosidase in a concentration-dependent manner with the IC50 of 36.3 µg/mL. An enzyme-kinetic analysis using a Lineweaver-Burk plot indicated that the inhibition of α-glucosidase by the herb extract is an uncompetitive type with the inhibition constant (K(i)) of 39.8 µg/mL. An intragastric pretreatment of 1,000 mg/kg A. crassna in STZ-NA-induced type-2 DM significantly lowered the blood glucose at 30 and 60 min after an oral loading of 2 g/kg glucose (p < 0.05 and p < 0.01, respectively), as compared with the untreated-diabetic control. After 4 weeks-daily administration of 500 and 1,000 mg/kg A. crassna extract, the blood glucose levels were significantly reduced by about 66% and 86%, respectively, as compared with the untreated-diabetic control (p < 0.01). However, the expression of GLUT4 in skeletal muscle, detected by ELISA, was not significantly changed with the herb extract. In conclusion, our findings are the first to clearly demonstrate the hypoglycemic effects of A. crassna and to propose the α-glucosidase inhibition as an antidiabetic mechanism of the herb activity.