Chemical Biopreservative Effects of Red Seaweed on the Shelf Life of Black Tiger Shrimp (Penaeus monodon).

Hypnea musciformis (HM) and Acanthophora muscoides (AM) red seaweeds were evaluated for their antioxidant properties and efficacy to extend the chemical shelf life of black tiger shrimp (Penaeus monodon) during 14-daystorage. Treated shrimp were soaked in five percent ethanolic solution with 500 µg/mL of AM or HM powder for 30 min. HM had more phenols and flavonoids, increased radical scavenging activity, and greater H2O2 reducing power than AM in vitro. Biochemical quality indicators were significantly higher in the control group, followed by HM- and AM-treated samples during storage. On day 14 of storage, controls contained significantly higher amounts of biogenic amines than HM- or AM-treated samples. The shelf life of chilled stored shrimp increased due to the presence of compounds of butylated hydroxytoluene, sulfurous acid, heptadecane, mono (2-ethylhexyl), and 1,2-propanediol found in AM extract and sulfurous acid and 1,2-propanediol found in HM extract. A control group was soaked in the same ethanolic solution as treated samples without algae powder for 30 min. Each group was kept ice-cold during the soaking period. The results obtained demonstrate the usefulness of two seaweed extracts, Hypnea musciformis and Acanthophora muscoides, combined with ice by decreasing the formation of toxic biogenic amines in shrimp, enhancing its shelf life during ice storage.

Changes on biogenic, volatile amines and microbial quality of the blue swimmer crab (Portunus pelagicus) muscle during storage.

Biogenic amines (BAs) are a group of substances with low molecular weight organic compounds such as aliphatic, aromatic or heterocyclic structures that are naturally present in animal tissues. The aim of this study was to investigate the changes on the formation of biogenic amine, bacterial load and biochemical characteristics in blue swimmer crab (Portunus pelagicus) at different storage temperatures (4 and 20 °C) up to 96 h. From seven BAs only four biogenic amines (tryptamine, putrescine, histamine, and tyramine) were detected while, the cadaverine, spermidine and spermine were absent in all investigated samples. Histamine was the major biogenic amine formed during the storage times and reached the highest concentration of 7.55 ± 0.46 mg/100 g and 17.68 ± 1.30 mg/100 g after 96 h at 4 and 20 °C, respectively. This level of histamine exceeded the maximum tolerance level of 5 mg/100 g. However, the proper icing procedure retarded the histamine effects, resulting only 7.55 mg/100 g after 96 h of ice storage. Spoilage indicator putrescine was only detected after 24-96 h of storage at 4 and 20 °C, respectively. The total volatile base nitrogen and the trimethylamine-nitrogen concentrations were considered to be reliable indicators of freshness index in blue swimmer crab. An aerobic mesophilic plate count of 6.68 and 7.31 log CFU/g were noted for crab stored in ice and ambient temperature after 96 h storage, respectively. It could be concluded that the biogenic amine forming bacteria and other susceptible perishing factors responsible for the biogenic amine formation could be prevented by continuous storage of P. pelagicus at low temperature.

Anticancer activity of silver and copper embedded chitin nanocomposites against human breast cancer (MCF-7) cells.

Chitin is a natural biopolymer widely used in biomedical and environmental applications due to its distinctive physical, chemical and mechanical properties. Although the anticancer property of chitin nanoforms and chitin derivatives against various cancers were studied earlier, there is no report in the chitin nanostructure incorporated metal nanocomposite. The present study was aimed to investigate the cytotoxicity of chitin incorporated silver and copper nanocomposite against human breast cancer (MCF-7) cells. Cytotoxicity of chitin nanoparticles (CNP), silver nanoparticles (AgNP), copper nanoparticles (CuNP), chitin/silver nanocomposite (CNP/AgNP) and chitin/copper nanocomposite (CNP/CuNP) was evaluated. Among all the above, CNP/AgNP has shown a lower of 31 mg as inhibitory concentration (IC50) value. Our study further showed the increased generation of reactive oxygen species with decreased activity of antioxidant enzymes and damage in the membrane integrity, thus confirms the cellular cytotoxic action of CNP/AgNP. In conclusion, the present study validates that, incorporating chitin nanoparticles with metallic nanostructure could be an effective and promising therapeutic agent against breast cancer.

Studies on electrochemical glucose sensing, antimicrobial activity and cytotoxicity of fabricated copper nanoparticle immobilized chitin nanostructure.

In this study, copper nanoparticle immobilized chitin nanocomposite (CNP/CuNP) was synthesized and used for the development of non-enzymatic electrochemical sensor. The CNP/CuNP was characterized by X-ray diffraction (XRD), fourier transform infra red (FTIR) spectroscopy and high resolution transmission electron microscopy (HRTEM) analysis. The glucose sensing property of CNP/CuNP was investigated by cyclic voltammetry (CV) and chronoamperometry (CA). As a result of the synergistic effect of CNP and CuNP, the modified electrode displayed effective electro-oxidation of glucose in 0.1M NaOH solution. At 0.45V potential the modified electrode showed response towards glucose in the linear range of 1-1000µM with a lowest detection limit of 0.776µM with better selectivity and stability. In addition, the antimicrobial activity of CNP/CuNP was evaluated against bacterial and fungal strains. CNP/CuNP displayed enhanced antimicrobial activity when compared to CNP and CuNP alone. Similarly, cytotoxicity of CNP/CuNP was tested against Artemia salina, which showed no toxic effect in the tested concentration.

Exploration of potential EGFR inhibitors: a combination of pharmacophore-based virtual screening, atom-based 3D-QSAR and molecular docking analysis.

Epidermal growth factor receptor (EGFR) protein tyrosine kinases are over expressed in several human cancers and considered as a promising target for developing novel anticancer drugs. In this study, the ligand-based pharmacophore mapping and atom-based 3D-QSAR approach was carried out on a series of 40 novel pyrrolo[3, 2-d]pyrimidine derivatives acting as EGFR inhibitors. The best pharmacophore hypothesis AAADRR.295 was selected and an atom-based 3D-QSAR model was generated by applying partial least-squares algorithm. The developed model was validated and used as a 3D query in sequential virtual screening study to filter five chemical databases. The obtained compounds were further filtered according to Lipinski rule of five and fitness score. Subsequently, a multistep molecular docking study was employed on the retrieved hits and finally, 12 compounds were prioritized as potential leads against EGFR, which exhibited high docking scores, correlated binding mode to experimentally proven compounds and constructive drug-like properties. The results of this study provide detailed structural insights and emphasize the important binding features of these compounds, which may assists in the design and development of novel EGFR inhibitors.