The Effect of Ethanol Extract from Mesua ferrea Linn Flower on Alzheimer's Disease and Its Underlying Mechanism.

The effects of Mesua ferrea Linn flower (MFE) extract on the pathogenic cascade of Alzheimer's disease (AD) were determined by an in vitro and cell culture model in the search for a potential candidate for the treatment of AD. The 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay exhibited that the MFE extract had antioxidant activities. According to the Ellman and the thioflavin T method's result, the extracts could inhibit acetylcholinesterase and ß-amyloid (Aß) aggregation. Studies on neuroprotection in cell culture found that the MFE extract could reduce the death of human neuroblastoma cells (SH-SY5Y) caused by H2O2 and Aß. Western blot analysis exhibited that the MFE extract alleviated H2O2-induced neuronal cell damage by downregulating the pro-apoptotic proteins, including cleaved caspase-3, Bax, and by enhancing the expression of anti-apoptotic markers including MCl1, BClxl, and survivin. Moreover, MFE extract inhibited the expression of APP, presenilin 1, and BACE, and increased the expression of neprilysin. In addition, the MFE extract could enhance scopolamine-induced memory deficit in mice. Overall, results showed that the MFE extract had several modes of action related to the AD pathogenesis cascade, including antioxidants, anti-acetylcholinesterase, anti-Aß aggregation, and neuroprotection against oxidative stress and Aß. Therefore, the M. ferrea L. flower might be a possibility for further development as a medication for AD.

Multifunctionality of Clausena harmandiana Extract and Its Active Constituents against Alzheimer's Disease.

This study was designed to investigate the effects of the root-bark extract of Clausena harmandiana (CH) and its active constituents (nordentatin and 7-methoxyheptaphylline) on pharmacological activities regarding selected targets associated with AD, namely, its antioxidant activity, inhibition of Aß aggregation, acetylcholinesterase (AChE) activity, and neuroprotective effects. The effect of the CH extract on the cognitive impairment induced by scopolamine was also evaluated in mice. The effects of the CH extract and its active constituents on radical scavenging, Aß aggregation, and AChE activity were investigated with a 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) assay, a thioflavin-T assay, and Ellman's method. The neuroprotective effects of the extract against hydrogen-peroxide and Aß toxicity were evaluated with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. In addition, the effects on cognitive impairment induced by scopolamine in mice were evaluated using Morris-water-maze and modified-Y-maze test models. The results of the present study demonstrate that the root-bark extract of CH shows multimodal actions relevant to the AD pathological cascade, including antioxidant effects, the inhibition of Aß aggregation, the inhibition of AChE function, and neuroprotection against oxidative stress and Aß toxicity. The extracts could improve both the short- and long-term memory deficits induced by scopolamine in mice.

Production of carbazole alkaloids through callus and suspension cultures in Clausena harmandiana.

Carbazole alkaloids are major constituents in Clausena spp. and exhibit a wide range of biological activities. The roots of Clausena harmandiana are a rich source of active carbazole alkaloids. However, its roots take several years to grow to be able to harvest. To obtain an alternative source of carbazole alkaloids, in vitro callus cultures of C. harmandiana were induced, and the formation of two active carbazole alkaloids was investigated. The effects of precursor, concentrations of sucrose, elicitors and light were studied to improve carbazole alkaloids formation. In this study, light had a strong effect on the formation of both carbazole alkaloids. The highest yields of clausine K and 7-methoxymukonal were 4.74 ± 0.26 and 0.92 ± 0.04 mg/g DW, respectively, which have more than 10-fold found in intact roots. According to the results of this study, C. harmandiana callus cultures can be used as an alternative source of carbazole alkaloids for additional biological studies.

Simultaneous determination of nine analytes in Clausena harmandiana Pierre. by new developed high-performance liquid chromatography method and the influence of locations in Thailand on level of nordentatin and dentatin.

BACKGROUND: Clausena harmandiana Pierre. (CH) contains various bioactive analytes with pharmacological benefits. Most researches were focused on carbazole analytes determined by isocratic high-performance liquid chromatography (HPLC), only few were focused on coumarin analytes and harvested location. OBJECTIVE: To develop and validate gradient HPLC method to analyze the variance of nine target analytes contained in roots of CH grown naturally in four different provinces of Thailand. MATERIALS AND METHODS: The analytical method was undertaken by gradient HPLC with 3% tetrahydrofuran in acetonitrile, and 0.05% phosphoric acid in water as mobile phases, on Hypersil ODS column (4.0 × 250 mm, 5 µm), at flow rate 1.0 mL/min and detected at wavelength 280 nm. The method was validated for system linearity, limit of detection, limit of quantitation, precision and accuracy. RESULTS: The new-developed method was able to detect the nine target analytes in CH root. The validation showed the reliability of the method. All system suitability parameters were within the satisfied limits. The linear responses of method were observed at r (2) ≥ 0.999 for all analytes. The obtained amount of nine analytes showed the biodiversity of contents in different provinces. Of the nine target analytes, the level of nordentatin and dentatin in coumarin groups were considerably high in plants collected from one specific province of Thailand. CONCLUSION: This study has shown that the new-developed method is reliable, precise, accurate and sensitive to determine and quantify the nine target analytes in CH. Nordentatin and dentatin obviously show the higher level in one specific province of Thailand.

Differentiation of opium and poppy straw using capillary electrophoresis and pattern recognition techniques.

Opium samples from four different locations and poppy straw from different plant varieties have been assayed using micellar capillary electrophoresis incorporating a sweeping technique. Individual alkaloids (morphine, codeine, papaverine, noscapine, thebaine, oripavine, reticuline and narceine) were quantitatively determined in the different samples by a validated capillary electrophoresis method. Unsupervised pattern recognition of the opium samples and the poppy straw samples using hierarchical cluster analysis (HCA) and principal component analysis (PCA), showed distinct clusters. Supervised pattern recognition using soft independent modelling of class analogy (SIMCA) was performed to show individual groupings and allow unknown samples to be classified according to the models built using the CZE assay results.

Membrane transport of andrographolide in artificial membrane and rat small intestine.

In the present study, the possible drug interactions of andrographolide with co-administering drugs such as acetaminophen, amoxycillin, aspirin, chlorpheniramine and norfloxacin to treat various infectious and inflammatory diseases that may be induced during absorption process were examined using artificial lipophilic membrane and everted rat intestine. The membrane transport of andrographolide across the artificial membrane was not affected by different pH of the medium (simulated gastric and intestinal fluids), different concentrations of andrographolide and co-administered drugs examined. In everted rat intestine, above co-administered drugs examined showed no significant effect on andrographolide membrane transport. The participation of efflux transporters such as P-glycoprotein and MRP2 in andrographolide transport was then examined, since andrographolide is a diterpene compound and some diterpene compounds are known as P-glycoprotein substrates. Cyclosporine, a P-glycoprotein/MRP2 inhibitor, significantly suppressed the efflux transport of andrographolide in distal region of intestine, whereas probenecid, an MRP inhibitor, showed no significant effect in both proximal and distal regions of intestine. These results suggest that P-glycoprotein, but not MRP, is participated in the intestinal absorption of andrographolide and P-glycoprotein-mediated drug interactions occur depending on the co-administered drugs and its concentrations.

Pharmacokinetic and pharmacodynamic assessment of co-amoxiclav in the treatment of melioidosis.

OBJECTIVES: We conducted a prospective pharmacokinetic study of oral co-amoxiclav in patients with melioidosis to determine the optimal dosage and dosing interval in this potentially fatal infection. PATIENTS AND METHODS: Serial plasma concentrations were measured after administration of two 1 g tablets of Augmentin (1750 mg of amoxicillin and 250 mg of clavulanate) to 14 adult patients with melioidosis. Monte Carlo simulation was used to predict the concentration of each drug following multiple doses of co-amoxiclav at different dosages and dose intervals. The proportion of the dose-interval above MIC (T > MIC) was calculated from 10,000 simulated subject plasma concentration profiles together with chequerboard MIC data from 46 clinical isolates and four reference strains of Burkholderia pseudomallei. RESULTS: The median (range) observed maximum plasma concentrations of amoxicillin and clavulanate were 11.5 (3.3-40.2) mg/L and 5.1 (0.8-12.1) mg/L, respectively. The median (range) elimination half-lives were 94 (73-215) and 89 (57-140) min, respectively. Simulation indicated that co-amoxiclav 1750/250 mg given at 4, 6, 8 or 12 hourly dosing intervals would be associated with a T > MIC of < or = 50% in 0.7%, 2.8%, 8.6% and 33.2% of patients, respectively. Corresponding proportions for T > MIC of > or = 90% were 95.8%, 78.6%, 50.2% and 10.8%, respectively. CONCLUSIONS: The dosing interval for co-amoxiclav (750/250 mg) in melioidosis should not be greater than 6 h.