Determination of phenanthrene and fluoranthene in rice samples by activated carbon-based dispersive solid phase micro-extraction coupled with gas chromatography-flame ionization detector analysis

A simple dispersive solid phase micro-extraction (DSPME) based on activated carbon (AC) was performed for the determination and separation of carcinogenic polycyclic aromatic hydrocarbons (PAHs), namely phenanthrene and fluoranthene, in selected white, brown and parboiled rice samples. The extraction was coupled with gas chromatography-flame ionization detector (GC-FID) for analysis. Under the optimized conditions [amount of adsorbent (5 mg), sample volume (40 mL), type (dichloromethane), and volume of desorption solvent (300 μL)], calibration curves were found to be linear for the concentration between 10 and 1000 μg kg-1 with coefficient of determination (R2) from 0.9938 to 0.9955. The limit of detection (LOD) and limit of quantification (LOQ) were in the range of 0.11 - 0.15 μg kg-1 and 0.33 - 0.46 μg kg-1, respectively. Relative standard deviation (RSD) was less than 8.02% and 5.48% for intra-day (n = 5) and inter-day (n = 5) for the present method, respectively. High pre-concentration factor (2587 - 2866) and satisfactory recoveries (90.23 - 115.63%) were also achieved. The proposed method was found to be simple, rapid and reliable for the monitoring of PAHs in rice samples

Cardamonin attenuates hyperalgesia and allodynia in a mouse model of chronic constriction injury-induced neuropathic pain: possible involvement of the opioid system

Neuropathic pain arises from the injury of nervous system. The condition is extremely difficult to be treated due to the ineffectiveness and presence of various adverse effects of the currently available drugs. In the present study, we investigated the antiallodynic and antihyperlagesic properties of cardamonin, a naturally occurring chalcone in chronic constriction injury (CCI)-induced neuropathic pain mice model. Our findings showed that single and repeated dose of intra-peritoneal administration of cardamonin (3, 10, 30 mg/kg) significantly inhibited (P<0.001) the chronic constriction injury-induced neuropathic pain using the Hargreaves plantar test, Randall-Selitto analgesiometer test, dynamic plantar anesthesiometer test and the cold plate test in comparison with the positive control drug used (amitriptyline hydrochloride, 20 mg/kg, i.p.). Pre-treatment with naloxone hydrochloride (1 mg/kg, i.p.) and naloxone methiodide (1 mg/kg, s.c) significantly reversed the antiallodynic and antihyperalgesic effects of cardamonin in dynamic plantar anesthesiometer test and Hargreaves plantar test, respectively. In conclusion, the current findings demonstrated novel antiallodynic and antihyperalgesic effects of cardamonin through the activation of the opioidergic system both peripherally and centrally and may prove to be a potent lead compound for the development of neuropathic pain drugs in the future

Synthesis and characterization of polyaniline for hydrazine detection / Kavirajaa Pandian Sambasevam

Among the conducting polymers, polyaniline (PAni) is studied most extensively due to the ease of synthesis, high conductivity and low production cost. Hydrazine from fuels, pesticide and corrosion inhibitor industries are a toxic compound which can cause neurotoxicity and carcinogenicity. In this study, a series of PAni were synthesized and applied as a chemical sensor for hydrazine detection. The sensor responses of PAni were monitored by ultraviolet-visible (UV-Vis) analysis in hydrazine detection. Besides, the sensor response was supported by conductivity study and Fourier transform infrared (FTIR) analysis to identify the chemical interaction between the PAni and the hydrazine. Doped-PAni were synthesized through chemical oxidative polymerization by using different sodium dioctyl sulfosuccinate salt dopant ratio (monomer:dopant = 5:3,5:5,5:7) under various polymerization temperatures (-10 ˚C to 25 ˚C). Similar procedure was repeated by addition of TiO2 nanoparticles (10 – 40%) through in-situ polymerization to produce PAni/TiO2 nanocomposites. FTIR, UV-Vis and x-ray diffractometry (XRD) analysis confirmed the chemical structure of all PAni. Conductivity, morphology and elemental analysis of doped-PAni were studied by resistivity meter, field emission scanning electron microscope (FESEM) and energy dispersive x-ray (EDX) analysis, respectively. For chemical sensor study, all PAni showed significant decrease at polaron peak (~780 nm) in UV-Vis spectra upon immersion in hydrazine. Doped-PAni synthesized with highest dopant ratio (5:7) at subzero polymerization temperature (-5 ˚C) provided more reactive sites to interact with hydrazine, thus giving rapid response time (7 s) with highest sensitivity compare to those with lower dopant ratio and other temperatures. Besides, PAni/TiO2 nanocomposites (5:7, -5 ˚C) with addition of 20% TiO2 offered good synergetic effect between PAni and TiO2 in order to detect hydrazine more effectively. The conductivity response for PAni (5:7, -5 ˚C, 20% TiO2) in hydrazine detection showed significant decrease in conductivity due to the reduction by hydrazine to convert conducting PAni (emeraldine salt-ES) to insulating PAni (leucoemeraldine-LE). Besides that, FTIR analysis of PAni showed decrease in the intensity ratio of quinoid/benzenoid (IQ/IB) from ~1 to 0.80 (increment in benzenoid units) upon immersion of PAni in hydrazine. FTIR analysis showed good agreement with conductivity data because LE consists of more benzenoid unit compared to ES. PAni (5:7, -5 ˚C, 20% TiO2) exhibited good reusability up to 10 cycles and excellent selectivity in the presence of interfering species such as 2-propanol, sodium hydroxide, formic acid and ammonia in hydrazine detection. The method validation of PAni (5:7, -5 ˚C, 20% TiO2) by UV-Vis measurement showed a linear calibration curve for hydrazine (0.05 – 5.00 ppm) with good correlation coefficient of 0.9928 and limit of detection (LOD) of 0.05 ppm (lower than OSHA standard:1 ppm). PAni (5:7, -5 ˚C, 20% TiO2) showed excellent recovery (93 – 105 %) and good relative standard deviation (R.S.D.) (0.3 – 4.2 %) for spiked real samples in laboratory tap water and river water (0.5 – 1.0 ppm) during hydrazine detection. In conclusion, PAni (5:7, -5 ˚C, 20% TiO2) that exhibited rapid response, highest sensitivity, satisfactory recovery (real sample), good reusability and selectivity is highly recommended as chemical sensor for hydrazine detection

Antihyperalgesic and anti-allodynic properties of cardamonin in mice model of neuropathic pain

Neuropathic pain is a chronic pain state caused by injury in the nervous system and often characterised by symptoms such as spontaneous pain, allodynia and hyperalgesia. Neuropathic pain is debilitating and highly resistant to current treatments such as nonsteroidal anti-inflammatory drugs (NSAIDS), anticonvulsants, antidepressants and opioids analgesics. Cardamonin is a naturally occurring chalcone. Studies have shown that cardamonin exhibited promising therapeutic effects such as antinociceptive and anti-inflammatory. Importantly, cardamonin is able to reduce the production of inflammatory mediators that are also involved in the pathophysiology of neuropathic pain. The study was aimed to investigate the antihyperalgesic and anti-allodynic properties of cardamonin in CCI-induced neuropathic pain in mice and its possible mechanism of actions. Male ICR mice were used throughout the project. CCI-induced neuropathic pain model was performed. A small incision was made to expose the sciatic nerve on the left hind leg and loose ligatures were placed around the nerve. The neuropathic pain response was measured quantitatively by using Hargreaves Plantar test, dynamic plantar aesthesiometer test, cold plate test and Randall-Selitto test. Ligations study consisted of 5 groups of animals; sham-operated, 1-Ligation, 2-Ligations, 3- Ligations and 4-Ligations. Behavioural assessments were carried out for 12 weeks. Investigation of antihyperalgesic and anti-allodynic properties of cardamonin were carried out by treating animals exposed to CCI with vehicle (DMSO, Tween20, & distilled water), Amitriptyline (20 mg/kg) or cardamonin (3, 10 & 30 mg/kg) via intraperitoneal route. All treatments were administered for 7 days consecutively from day 15 till day 21 after surgery. Behavioural assessments were carried out on day 0, 14 (before treatment & after treatment) and 21. Mechanisms of actions (MOA) that were investigated in this project were the involvement of opioid receptors, L-arginine-nitric oxide/cGMP/ATP-sensitive K+ channel pathway and potassium channels. Animals exposed with CCI were pre-treated with antagonists before the administration of cardamonin or vehicle. Behavioural tests were conducted after the administration of their respective treatments. Brain samples were collected to study the expression of opioid receptors via Western blotting. All data were collected and expressed as mean ± SEM and were statistically analysed by using one-way Analysis of Variance (ANOVA), followed by Tukey‘s post-hoc test. The results were considered significant at p<0.05. Cardamonin (3, 10 & 30 mg/kg) exhibited antihyperalgesic and anti-allodynic activities on CCI-induced neuropathic pain model in mice. Cardamonin elicited its analgesic effects by activating L-arginine/cGMP/K+-ATP channel pathway, opening the potassium channels as well as modulating pain signal via activation of delta- and kappaopioid receptors. Modulation by these pathways and ion channels suppressed the neuronal hyperexcitability that arised due to peripheral nerve injury, hence producing analgesic effects. Taken together, cardamonin has the potential to be developed as a drug candidate for management of pain

Synthesis and Characterization of the Inclusion Complex of β-cyclodextrin and Azomethine

Abstract: A β-cyclodextrin (β-Cyd) inclusion complex containing azomethine as a guest was prepared by kneading method with aliquot addition of ethanol. The product was characterized by Fourier Transform Infrared (FTIR) spectrometer, 1 H Nuclear Magnetic Resonance ( 1 H NMR) and Thermogravimetric Analyzer (TGA), which proves the formation of the inclusion complex where the benzyl part of azomethine has been encapsulated by the hydrophobic cavity of β-Cyd. The interaction of β-Cyd and azomethine was also analyzed by means of spectrometry by UV-Vis spectrophotometer to determine the formation constant. The formation constant was calculated by using a modified Benesi-Hildebrand equation at 25 °C. The apparent formation constant obtained was 1.29 × 10 4 L/mol. Besides that, the stoichiometry ratio was also determined to be 1:1 for the inclusion complex of β-Cyd with azomethine

Solar-driven Degradation of 2-Chlorophenol Using PANI/GO as Photocatalyst

Confiscation of organic pollutants from the environment is one the most important topics recently. The contamination of our water body that comes from several pollutants lead to several serious effects to the environment. The development of green and economical method in reducing the contamination is well discussed.  The main aim of this research is to characterize and investigate the solar driven photocatalytic degradation of 2-chlorophenol (2-CP) from aqueous solution with the aid of polyaniline (PANI) incorporated graphene oxide (GO) composite (PANI/GO). PANI was incorporated with GO via in-situ oxidation polymerization method using ammonium persulfate (APS) as oxidizing agent to form composite. Three compositions of PANI/GO composites were synthesized with the ratio of PANI and GO of 1:1, 1:4 and 9:1. PANI, GO and PANI/GO composites were characterized comprehensively using Fourier transform infrared (FTIR), UV-visible (UV-VIS) and XRD spectroscopy analysis. Morphology was analyzed by capturing the images using Scanning electron microscope (SEM) with Energy Dispersive X-ray (EDX) analysis setup. The characterization studies revealed that, the PANI/GO composites have been successfully synthesized. Degradation of 2-CP was conducted using PANI/GO composites under solar irradiation for 3 hours. The degradation results disclosed that, PANI/GO composite with composition ratio of 1:1 possessed the highest degradation percentage with 75 % at degradation time of 150 minutes. Therefore, PANI/GO composites are one of the ideal catalysts in order to degrade 2-CP. DOI: http://dx.doi.org/10.17807/orbital.v12i4.1513 </p

Experimental characterization of the chronic constriction injury-induced neuropathic pain model in mice

Number of ligations made in the chronic constriction injury (CCI) neuropathic pain model has raised serious concerns. We compared behavioural responses, nerve morphology and expression of pain marker, c-fos among CCI models developed with one, two, three and four ligations. The numbers of ligation(s) on sciatic nerve shows no significant difference in displaying mechanical and cold allodynia, and mechanical and thermal hyperalgesia throughout 84 days. All groups underwent similar levels of nerve degeneration post-surgery. Similar c-fos level in brain cingulate cortex, parafascicular nuclei and amygdala were observed in all CCI models compared to sham-operated group. Therefore, number of ligations does not impact intensity of pain symptoms, pathogenesis and neuronal activation. A single ligation is sufficient to develop neuropathic pain, in contrast to the established model of four ligations. This study dissects and characterises the CCI model, ascertaining a more uniform animal model to surrogate actual neuropathic pain condition