Rapid Colorimetric and Fluorometric Discrimination of Maleic Acid vs. Fumaric Acid and Detection of Maleic Acid in Food Additives.

An anthracene thiazole based Schiff base L was synthesized and employed for fluorescence switch-on detection of maleic acid in aqueous DMSO. The non-fluorescent L (10-5 M) showed an instantaneous and selective fluorescence enhancement at 506 nm upon interaction with maleic acid (10-5 M). Other potential carboxylic acids (10-5 M), such as malic acid, citric acid, acetic acid, cinnamic acid, tartaric acid, succinic acid, fumaric acid, oxalic acid and malonic acid failed to alter the chromo-fluorogenic properties of L. Probe L can be employed to detect maleic acid down to 2.74 × 10-6 M. The probe L showed good linearity from 2.97 to 6.87 µM. Analytical utility of L was examined by detecting maleic acid in various food additives and drosophila larvae.

Surface functionalization of electrospun PAN nanofibers with ZnO-Ag heterostructure nanoparticles: synthesis and antibacterial study.

In this work, we have prepared polyacrylonitrile (PAN) polymer nanofibers by electrospinning method. The surface of the electrospun PAN nanofibers membrane has been functionalized with ZnO-Ag heterostructure nanoparticles by using three different chemical pathways such as reflux, blending, hydrothermal methods and accordingly the prepared composite nanofibers membranes were named as PAN/ZnO-Ag (R), PAN/ZnO-Ag (B) and PAN/ZnO-Ag (H) respectively. The obtained heterostructure nanoparticles functionalized PAN nanofibers membranes were characterized using ATR-FTIR, XRD, FESEM and TEM analytical techniques. From the FESEM and TEM images it was clearly observed that 20-30 nm size spherical nanoparticles have been decorated uniformly on the surface of PAN nanofibers. XRD study confirmed the formation of ZnO-Ag mixed/hybrid nanoparticles on PAN nanofibers surface. The ZnO-Ag heterostructure nanoparticles functionalized PAN nanofibers membranes were used for antibacterial application. It was observed from inhibition zone study that the ZnO-Ag heterostructure nanoparticles functionalized PAN nanofibers membrane shows excellent antibacterial properties towards both gram-negative Escherichia coli and gram-positive Micrococcus luteus bacteria than their single component counterparts. Thus this study demonstrated the simple and cost-effective approach to develop antibacterial functional membrane that has many potential applications in water and air filtration, protective mask, textile and packaging industries.

Protein interactions, molecular docking, antimicrobial and antifungal studies of terpyridine ligands.

Resistance to antibiotics/antibacterials/antifungals in pathogenic microbes has been developing over the past few decades and has recently become a commonplace public-health peril. Thus, alternative nontoxic potent antibiotic agents are covertly needed to control antibiotic-resistant outbreaks. In an effort to combat the challenges posed by the co-occurrence of multidrug resistance, two terpyridine ligands 4'-(4-N,N'-dimethylaminophenyl)-2,2':6',2″-terpyridine (L1) and 4'-(4-tolyl)-2,2':6',2″-terpyridine (L2) have been designed, prepared and confirmed their structure by spectral studies. Thereafter, antimicrobial assay was performed against gram positive and negative bacterial strains along with fungal strains. Both compounds L1 and L2 exhibited remarkable inhibitory activities against bacteria, Escherichia coli and Staphylococcus aureus at MIC values 6.25 and 3.125 µg/ml, respectively. In addition, in silico molecular docking studies were ascertained with bacterial DNA gyrase and fungal demethylase. Furthermore, both L1 and L2 could bind Bovine Serum Albumin (BSA) protein and binding interaction has been studied with the help of UV-Visible and fluorescence spectroscopy. While fluorescence of BSA unperturbed in the presence of L2, an addition of L1 to the solution of BSA resulted significant quenching. The binding constant calculations at different temperature confirmed that the fluorescence quenching between BSA and L1 is predominantly static in nature. The toxicity of L1 and L2 was checked using Drosophila melanogaster. The toxicity analysis suggest both the dyes are non-cytotoxic in nature.Communicated by Ramaswamy H. Sarma.

Evaluation of antiasthmatic activity of ethanolic extract of Elephantopus scaber L. leaves.

AIMS: The aim of study was to evaluate the scientific basis for the traditional use of Elephantopus scaber leaves. MATERIALS AND METHODS: In the present study, ethanol extract of Elephantopus scaber leaves was evaluated for preliminary phytochemical screening and antiasthmatic activity using histamine and acetylcholine-induced bronchospasm, mast cell degranulation and histamine induced constriction on isolated guinea pig tracheal chain at different dose levels. Student's t-Test and Dunett's test were used for statistical analysis. RESULTS: The result of present investigation showed that the ethanolic extract of E. scaber significantly (P<0.001) decreased the bronchospasm induced by histamine, acetylcholine and protected mast cell degranulation as compared to control groups. It also decreased the histamine induce constriction on isolated guinea pig trachea in dose-dependent manner. Phytochemical studies revealed the presence of steroids, saponin, flavonoids, and phenolic compounds in the extract. CONCLUSIONS: The present study concludes that the antiasthmatic activity of ethanolic extract of E. scaber leaves may be due to the presence of flavonoids or steroids. Antiasthmatic action of the E. scaber could be due to its antihistaminic, anticholinergic and mast-cell-stabilizing property.