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Neuropathic pain is a chronic pain condition persisting past the presence of any noxious stimulus or inflammation. Zerumbone, of the Zingiber zerumbet ginger plant, has exhibited anti-allodynic and antihyperalgesic effects in a neuropathic pain animal model, amongst other pharmacological properties. This study was conducted to further elucidate the mechanisms underlying zerumbone’s antineuropathic actions. Research on therapeutic agents involving cannabinoid (CB) and peroxisome proliferator-activated receptors (PPARs) is rising. These receptor systems have shown importance in causing a synergistic effect in suppressing nociceptive processing. Behavioural responses were assessed using the von Frey filament test (mechanical allodynia) and Hargreaves plantar test (thermal hyperalgesia), in chronic constriction injury (CCI) neuropathic pain mice. Antagonists SR141716 (CB1 receptor), SR144528 (CB2 receptor), GW6471 (PPARα receptor) and GW9662 (PPARγ receptor) were pre-administered before the zerumbone treatment. Our findings indicated the involvement of CB1, PPARα and PPARγ in zerumbone’s action against mechanical allodynia, whereas only CB1 and PPARα were involved against thermal hyperalgesia. Molecular docking studies also suggest that zerumbone has a comparable and favourable binding affinity against the respective agonist on the CB and PPAR receptors studied. This finding will contribute to advance our knowledge on zerumbone and its significance in treating neuropathic pain.

A unique, non-leaching and durable novel anti-biocide polyacrylamide-starch coating (pAam-g-S) has successfully been synthesized. In this study, a grafted cationic-functionalized polymeric coating was designed and cross-linked with native starch extracted from Dioscorea hispida sp. yam to afford multifunctional anti-fungal and anti-termite coating. Leaching of the disinfectant into the environment was eliminated because no toxic chemicals were used. The copolymerization was successfully carried out to produce various ratios of pAam-g-S coating using modification of starch-gel. Results obtained from Fourier Transform Infrared-Attenuated Total Reflectance (FTIR-ATR) confirmed the monomer pAam was grafted onto the starch backbone as shown by the cross-linked peak at 1642 cm−1. Supported by differential scanning calorimetry (DSC), the highest transition glass temperature was observed at 154 °C. The coating was designed to continuously decontaminate against pathogenic fungus and termite in addition to afford preliminary anti-biocides properties. Facile anti-fungal and anti-termite evaluations were conducted via total weight loss of wood (%) studies using white rot fungus, Pycnoporus. sanguineus and termite Coptotermes curvignathus respectively. In order to verify the coating performance, gel fractions, morphologies and heat resistant properties were also investigated.

The antimicrobial activities of eleven maleimide derivatives were tested in this study. Out of the eleven samples, N-(4fluorophenyl) maleimide, N-(4-chlorophenyl) maleimide and N-(4-bromophenyl) maleimide were synthesized by reacting maleic anhydride with 4-fluorophenylaniline, 4-chlorophenylaniline and 4-bromophenylaniline, respectively in the presence of acetic acid, by refluxing overnight. Crystals were successfully obtained after the products were recrystallized with different mixture of solvents. Their chemical structures were confirmed by infrared spectroscopy (IR), H and C Nuclear Magnetic Resonance (NMR) and melting point determination. Subsequently, all the samples were screened for their biological activity using disc diffusion method. The bacteria chosen for this study were Gram-negative Escherichia coli, Gram-positive Bacillus subtilis and yeast Saccharomyces cerevisae. Positive control for bacteria was streptomycin and nystatin for the yeast. M1 to M6 compounds gave remarkable result at low concentrations whereas M8, M9 and M11 compounds are mostly inactive up to a high concentration. In contrast, the unsubstituted maleimide, M7 was highly reactive towards both bacteria and yeast at low and high concentrations.

Being abundant in many tropical part of the world, Dioscorea sp. as food is limited due to its toxicity. However polysaccharides derive from these tubers could be important for other applications. Here we developed a Highly Luminescent Carbon Nanodots (C-dots) via acid hydrolysis of Gadong starch (GS). The hydrolysis rate of GS increased from 49% to 86% within 7 days while the X-ray diffraction showed the native GS particle is a C-crystalline type. The GS particles were either round or oval with diameters ranging from 50-90 nm. Further acid dehydration and surface oxidation reduced the size of GS nanoparticles to 6-25 nm. The C-dots produced a fluorescent emission at wavelength 441 nm. Toxicity tests demonstrate that zebrafish embryo were able to tolerate the C-dots for 48 h after exposure. This study has successfully demonstrated a novel approach of converting GS into excellent fluorescent C-dot.

A new route to the synthesis of maleimide is described. 2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)acetic acid maleimide (1) and 2-(4-(2,5-Dioxo-2,5-dihydro- 1H-pyrrol-1-yl)phenyl)ethanoic acid maleimide (2) have been synthesized by the reaction of maleic anhydride with glycine and 4-aminophenyl acetic aicd. Maleimide (1) was synthesized by conventional technique while maleimide (2) was synthesized by microwave method. The compounds were characterized using FT-Infrared (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopies and Mass Spectrometry.

Yields of a rotaxane can be improved by employing a two-step capture protocol. Cooling a solution of the linear and macrocyclic components required for the rotaxane increases the population of the target pseudorotaxane, which is then captured by a rapid capping reaction between an azide and PPh(3). The resulting iminophosphorane rotaxane can then be manipulated synthetically at elevated temperatures.

Synthesis of imine compounds usually results in moderate yield due its reversibility characteristic and prone to hydrolysis. Hence, to increase the formation of imine compound, self-replicating catalyst was introduced. The self-replicating catalyst is the imine product itself. The first imine compound, 4-{[4-(3,5-Dimethyl-phenylcarbamoyl)-benzylidene]-amino}-phenyl)-acetic acid has been synthesized from 4-Amino-N-(3,5-dimethyl-phenyl)-benzamide and (4-formyl-phenyl)-acetic acid. Simultaneously, 4-formylbenzoic acid was reacted with thionyl chloride to produce 4-formylbenzoyl chloride, which was then reacted with 2-amino-4,6-dimethylpyridine in the presence of triethylamine to afford N-(4,6-dimethyl-pyridin-2-yl)-4-formyl-benzamide. N-(4,6-dimethyl-pyridin-2-yl)-4-formyl-benzamide formed then reacted with 4-amino-2-methylbenzoic acid to form the second imine derivative, 4-{[4-(4,6-dimethyl-pyridin-2-ylcarbamoyl)-benzylidene]-amino}-2-methyl-benzoic acid. The concentration time profile for the synthesis of self-replicating imine 1 reveals the classic sigmoidal shape characteristics of an autocatalytic process and the rate of the reaction are higher than that observed in the absence of recognition. In order to demonstrate the nature of self-replicating catalyst, a preformed imine 1 was doped into the reaction mixture of amine 1 and the corresponding aldehyde, 4-formylbenzoic acid. The insertion of substoichiometric amounts (15 mol%) of imine 1 at the start of the reaction has accelerated the rate formation of imine 1.

A novel symmetrical macrocycle has been synthesised via oxidative homocoupling of bisalkyne, diprop-2-ynyl pyridine-2,6-dicarboxylate mediated by copper (I) iodide (CuI) and 4-dimethylaminopyridine (DMAP). The precursor compound was synthesised from 2,6-pyridine dicarbonyl dichloride and propargyl alcohol in the presence of triethylamine. The reaction mixture was stirred overnight and further purified via column chromatograpy with 76% yield. Single crystal for X-ray study was obtained by recrystallization from acetone. Subsequently, a symmetrical macrocycle was synthesised from oxidative homocoupling of precursor compound in open atmosphere. The crude product was purified by column chromatography to furnish macrocycle compound with 5% yield. Both compounds were characterised by IR, 1H and 13C NMR and mass spectral techniques. The unusual conformation of the bisalkyne and twisted conformation of designed macrocycle has influence the percentage yield. This has been studied thoroughly by X-ray crystallograph...