The Effects of 4-Hydroxybenzoic Acid Identified from Bamboo (Dendrocalamus asper) Shoots on Kv1.4 Channel

Background: Bamboo shoot has been used as a treatment for epilepsy in traditional Chinese medicine for generations to treat neuronal disorders such as convulsive, dizziness and headaches. 4-hydroxybenzoic acid (4-hba) is a non-flavonoid phenol found abundantly in Dendrocalamus asper shoots (bamboo), fruits (strawberries and apples) and flowers. Kv1.4 is a rapidly inactivating Shaker-related member of the voltage-gated potassium channels with two inactivation mechanisms; the fast N-type and slow C-type. It plays vital roles in repolarisation, hyperpolarisation and signaling the restoration of resting membrane potential through the regulation of the movement of K+ across the cellular membrane. Methods: Chemical compounds from Dendrocalamus asper bamboo shoots were purified and identified as major palmitic acids mixed with other minor fatty acids, palmitic acid, 4-hydroxybenzaldehyde, lauric acid, 4-hydroxybenzoic acid and cholest-4-ene-3-one. The response of synthetic 4-hydroxybenzoic acid was tested on Kv1.4 potassium channel which was injected into viable oocytes that was extracted from Xenopus laevis. The current were detected by the two-microelectrode voltage clamp, holding potential starting from −80 mV with 20 mV stepup until +80 mV. Readings of treatments with 0.1% DMSO, 4-hba concentrations and K channel blockers were taken at +60 mV. The ratio of tail/peak amplitude is the index of the activity of the Kv1.4 channels with n ≥ 6 (number of oocytes tested). The decreases of the ratios of five different concentrations (1 μM, 10 μM, 100 μM, 1 mM and 2.5 mM) were compared with 0.1% DMSO as the control. Results: All concentration showed statistically significant results with P < 0.05 except for 100 μM. The normalised current of the 4-hba concentrations were compared with potassium channel blockers (TEA and 4-AP) and all groups showed statistically significant results. This study also showed that time taken for each concentration to affect Kv1.4 does not play any significant roles. Conclusion: 4-hydroxybenzoic acid was found to be able to enhance the inactivation of Kv1.4 by lowering the membrane potential so that the abnormal neuronal firing can be inhibited. With IC50 slightly higher than 10 μM, increasing concentrations (100 μM, 1 mM and 2.5 mM) had shown to exhibit toxicity effects. The best concentration from this study is 10 μM with Hill slope of 0.1799.

3,5-Bis(arylidene)-4-piperidones as potential dengue protease inhibitors

Dengue is a severe mosquito-borne viral infection causing half a million deaths annually. Dengue virus NS2B/NS3 protease is a validated target for anti-dengue drug design. A series of hitherto unreported 3,5-bis(arylidene)-4-piperidones analogues-were synthesized and screenedagainst DENV2 NS2B/NS3 protease to elucidate their binding mechanism and orientation around the active sites. Results were validated through anDENV2 NS2B/NS3 protease assay using a fluorogenic Boc-Gly-Arg-Arg-AMC substrate. Nitro derivatives of 3,5-bis(arylidene)-4-piperidones (and) emerged as promising lead molecules for novel protease inhibitors with an ICof 15.22 and 16.23 µmol/L, respectively, compared to the standard, panduratin A, having ICof 57.28 µmol/L.

Metabolomics for characterization of gender differences in patients infected with dengue virus

OBJECTIVE@#To determine the metabolic response associate with dengue infection based on human gender metabolic differences by means of (1)H NMR-spectrometry.@*METHODS@#The mid-stream urine collected from both male and female patients diagnosed with dengue fever at Penang General Hospital and fourty-three healthy individuals were analyzed with (1)H NMR spectroscopy, followed by chemometric multivariate analysis. NMR signals which highlighted in the OPLS-DA S-plot were further selected and identified using Human Metabolome Database, Chenomx Profiler.@*RESULTS@#The results pointed out that NMR urine profiling was able to capture human gender metabolic differences that are important for the distinction of classes of individuals of similar physiological conditions; infected with dengue. Distinct differences between dengue infected patients versus healthy individuals and subtle differences in male versus female infected with dengue were found to be related to the metabolism of amino acid and tricarboxylic acid intermediates cycle.@*CONCLUSIONS@#The (1)H NMR metabolomic investigation combined with appropriate algorithms and pattern recognition procedures, gave an evidence for the existence of distinct metabolic differentiation of individuals, according to their gender, modulates with the infection risk.

Metabolomics for characterization of gender differences in patients infected with dengue virus

Objective: To determine the metabolic response associate with dengue infection based on human gender metabolic differences by means of 1H NMR-spectrometry. Methods: The mid-stream urine collected from both male and female patients diagnosed with dengue fever at Penang General Hospital and fourty-three healthy individuals were analyzed with 1H NMR spectroscopy, followed by chemometric multivariate analysis. NMR signals which highlighted in the OPLS-DA S-plot were further selected and identified using Human Metabolome Database, Chenomx Profiler. Results: The results pointed out that NMR urine profiling was able to capture human gender metabolic differences that are important for the distinction of classes of individuals of similar physiological conditions; infected with dengue. Distinct differences between dengue infected patients versus healthy individuals and subtle differences in male versus female infected with dengue were found to be related to the metabolism of amino acid and tricarboxylic acid intermediates cycle. Conclusions: The 1H NMR metabolomic investigation combined with appropriate algorithms and pattern recognition procedures, gave an evidence for the existence of distinct metabolic differentiation of individuals, according to their gender, modulates with the infection risk.

Evaluation of the Cytotoxicity of Levodopa and its Complex with Hydroxypropyl-ß-Cyclodextrin (HP-ß-CD) to an Astrocyte Cell Line

A simple, reliable a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfophenyl)-2H-tetrazolium, (MTS) assay was conducted to evaluate the potential cytotoxic effects of levodopa, a “gold standard therapy” for Parkinsonism, and its complex with Hydroxypropyl-β-Cyclodextrin (HP-β-CD) on an astrocyte cell line. The cells were incubated in a range of concentrations from 4.69 to 300 μg/mL levodopa, HP-β-CD or the complex for up to 72 hours. At every 24-hour interval, the optical density (OD), which reflects the number of viable cells, was recorded. In general, linear dose-dependent cytotoxicity profiles were observed for the cells subjected to levodopa or the complex, whereas a slightly triphasic response was observed for the cells exposed to HP-β-CD. A significant difference (P 200 μg/mL), exhibited improved tolerability in a time-dependent manner, which may indicate the potential ability of HP-β-CD to mask the toxic effects of levodopa via complexation.

Synthesis, spectroscopic and crystal structure studies of N,N'-Bis [2-hydroxy-3-methoxybenzylidene] diaminobenzene derivatives

The reaction of 0-vanillin 1 with phenylenediamine isomers 2-4 in dichloromethane formed three diaminobenzene derivatives: N,N'-bis [2-hydroxy-3-methoxybenzylidene]-1,2-diaminobenzene 5, N,N'-bis [2-hydroxy-3-methoxybenzylid-ene]-l,3-diaminobenzene 6 and N,N'-bis [2-hydroxy-3-methoxybenzylidene]-l,4-di-aminobenzene 7, respectively, All compounds were obtained as single crystals and the structures were determined by X-ray crystallography. All compounds were confirmed by FTIR, HRMS, ID and 2D NMR spectroscopy. The complete assignments of these compounds, using ID and 2D NMR including APT, DEPT-135, COSY, HMQC and HMBC in CDC1[3], will be discussed