Azila Idris

Dissolution of feather keratin in ionic liquids

Keratin from various livestock industries is currently a waste material that has potential as a source of polyamide polymers that could replace fossil fuel derived materials if processing methods can be developed. In this work we have investigated methods for the dissolution and regeneration of keratin. Dissolution of keratin (from turkey feather) in ionic liquids was conducted under nitrogen at 130 °C for 10 hours. It was found that [BMIM]Cl, [AMIM]Cl and [choline][thioglycolate] could dissolve turkey feather keratin without addition of solvent or other chemicals. A significant percentage of solubility was obtained, up to 45% by weight. A water insoluble fraction was recovered by addition of water to the solution (∼50%). The structure and properties of this regenerated, water insoluble fraction were investigated. Compared to the starting material, the regenerated keratin shows structural changes rather than chemical changes within the polypeptide chains. The remaining fraction, consisting of water soluble fragments, was characterised by gel electrophoresis.

Dissolution and regeneration of wool keratin in ionic liquids

Wool keratin, a natural biopolymer, is potentially an important renewable source of raw materials for the polyamide plastics industry. Large quantities of non-spinnable and short fibers of wool are discarded globally and hence are available as low value waste materials. In this study, we have investigated different solvents, including ionic liquids and deep eutectic mixtures, for the dissolution and processing of wool. The results show that substantial dissolution of wool (up to 475 mg wool per gram of solvent) can be obtained in the 1-allyl-3-methylimidazolium dicyanamide [AMIM][dca] ionic liquid at 130 °C. Our studies also indicated enhanced dissolution (an additional 50–100 mg g−1) of wool upon the addition of a reducing agent to the ionic liquids. Water insoluble fractions (20–40%) were obtained on the addition of water to the dissolved wool. This regenerated fraction was characterized for structural and chemical changes and found to contain a larger fraction of β-sheets and random coils than the starting material. The water soluble fraction was characterised and the results indicated the presence of fragments of low molecular weight polypeptide chains.

Evaluation of chemopreventive potential of Strobilanthes crispus against colon cancer formation in vitro and in vivo

BackgroundWith cancer being one of the major causes of death around the world, studies are ongoing to find new chemotherapeutic leads. There are common mechanisms for colorectal cancer (CRC) formation. Several are connected with oxidative stress-induced cell apoptosis and others are related to imbalanced homeostasis or intake of drugs/toxins. Plants that have been used for decades in folk and traditional medicine have been accepted as one of the commonest sources of discovered natural agents of cancer chemotherapy and chemoprevention. The aim was to study the antioxidant and chemopreventive effects of Strobilanthes crispus on colorectal cancer formation.MethodsFive groups of rats were injected subcutaneously with AOM, 15xa0mg/kg body weight, each once weekly for 2xa0weeks. The cancer group was continued on 10xa0% Tween-20 feeding for 8xa0weeks. The standard drug group was continued on 35xa0mg/kg 5-fluorouracil intraperitoneal injection twice a week for 8xa0weeks, and the experimental groups were continued on 250 and 500xa0mg/kg S. crispus extract oral feeding for 8xa0weeks, respectively. The normal group was injected subcutaneously with normal saline once a week for 2 weeks, followed by oral administration of 10xa0% Tween-20 for 8xa0weeks. All the rats were sacrificed after 10xa0weeks. The colons were evaluated grossly and histopathologically for aberrant crypt foci (ACF). Gene expression was performed for Bax, Bcl2, Defa24, Slc24a3, and APC genes by real-time PCR. S. crispus and its fractions were evaluated for their chemopreventive effects against human colorectal adenocarcinoma cell line HT29 and cytotoxicity for normal human colon epithelial cell line CCD 841, and the active fraction was assessed for its components.ResultsWe observed significant decrease in total colonic ACF formation, malonaldehyde (MDA) and lactate dehydrogenase (LDH), increase in superoxide dismutase (SOD), up-regulation of APC, Bax and Slc24a3, and down-regulation of Defa24 and Bcl-2 in rats treated with Strobilanthes crispus.ConclusionOur results support the in vivo protection of S. crispus against CRC formation (azoxymethane-induced aberrant crypt foci) and suggest that the mechanism is highly specific to protect from oxidative insults and the following apoptotic cascade.

N-(Pyrazin-2-yl)aniline.

The two aromatic rings in the title compound, C10H9N3, are inclined at 15.2u2005(1)° to each other; this opens up the angle at the amino N atom to 130.4u2005(1)°. The amino N atom forms a hydrogen bond to the 4-N atom of an adjacent molecule to create a chain motif.

2-(4-Chloro-anilino)quinoxaline.

There are two molecules in the asymmetric unit of the title compound, C14H10ClN3, with dihedral angles of 5.11u2005(10) and 13.61u2005(10)° between the aromatic ring systems. In the crystal structure, molecules are linked by N—H⋯N hydrogen bonds, resulting in chains propagating in [010].

N-(Pyrazin-2-yl)-4-toluidine

The two aromatic systems in the title compound, C11H11N3, are inclined by 19.1u2005(1)°, whilst the angle at the central amino N atom is 130.3u2005(2)°. The amino group forms a hydrogen bond to the pyrazine N-4 atom of an adjacent molecule, forming a chain motif.

Phenyl pyrazin-2-yl ether

In the title compound, C10H8N2O, the dihedral angle between the aromatic rings is 64.2u2005(1)° and the bridging C—O—C angle is 119.1u2005(1)°.

Ultrasonic technology for value added products from feather keratin

Feather keratin is a biomass generated in excess from various livestock industries. With appropriate processing, it holds potential as a green source for degradable biopolymer that could potentially replace current fossil fuel based materials. Several processing methods have been developed, but the use of ultrasonication has not been explored. In this study, we focus on (i) comparing and optimizing the dissolution process of turkey feather keratin through sonication and conventional processes, and (ii) generating a biodegradable polymer material, as a value added product, from the dissolved keratin that could be used in packaging and other applications. Sonication of feather keratin in pure ionic liquids (ILs) and a mixture containing ILs and different co-solvents was conducted under different applied acoustic power levels. It was found that ultrasonic irradiation significantly improved the rate of dissolution of feather keratin as compared to the conventional method, from about 2u202fh to less than 20u202fmin. The amount of ILs needed was also reduced by introducing a suitable co-solvent. The keratin was then regenerated, analyzed and characterized using various methods. This material holds the potential to be reused in various appliances.

N-(3-Methyl­phen­yl)quinoxalin-2-amine monohydrate

The quinoxaline system in the title hydrate, C15H13N3·H2O, is roughly planar, the r.m.s. deviation for the 18 non-H atoms being 0.188u2005Å; this conformation features a short intramolecular C—H⋯N(pyrazine) interaction. In the crystal, the amine H atom forms an N—H⋯O hydrogen bond to the water molecule, which in turn forms two O—H⋯N hydrogen bonds to the pyrazine N atoms of different organic molecules. These interactions lead to supramolecular arrays in the bc plane that are two molecules thick; additional π–π interactions stabilize the layers [ring centroid–centroid distance = 3.5923u2005(7)u2005Å]. The layers stack along the a-axis direction via C—H⋯π contacts.

N-(Quinoxalin-2-yl)-4-toluidine

The aromatic and the aromatic fused-rings in the title compound, C15H13N3, open the angle at the planar N atom to 130.07u2005(13) and 129.98u2005(13)° in the two independent molecules in the asymmetric unit. The amino N atom of one molecule forms a hydrogen bond to the 4-N atom of an adjacent quinoxalinyl ring, generating a supramolecular chain.