Biosynthesis of Zinc Oxide-Zerumbone (ZnO-Zer) Nanoflakes Towards Evaluating Its Antibacterial and Reactive Oxygen Species (ROS)-Dependent Cytotoxic Activity.

Being the second most prevalent metal oxide, zinc oxide (ZnO) nanomaterials have been widely studied and found to exhibit promising applications in various domains of biomedicine and agriculture. Considering the enhanced bioactivities displayed by secondary metabolite (SM) derived ZnO nanomaterials, present study was undertaken to evaluate the efficacy of ZnO nanoflake (NF) derived from Zerumbone (Zer), a sesquiterpenoid from Zingiber zerumbet rhizome with diverse pharmacological properties. ZnO NF prepared by homogeneous precipitation method using ZnSO4.7H2O (0.1 M) and NaOH (0.2 M) as precursors with and without the addition of Zer (0.38 mM) were characterized by powder UV-visible spectroscopy, X-ray diffraction (XRD), FT-IR spectroscopy and Field emission scanning electron microscope (FESEM) analysis. Optical and physical properties of ZnO-Zer NF were found to match with the typical ZnO nanomaterial properties. XRD analysis revealed reduction in size (15 nm) of the green synthesized ZnO-Zer NF compared to ZnO NF (21 nm). ZnO-Zer NF displayed linear correlation between concentration and antimicrobial activity to Salmonella typhi, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Determination of cytotoxic potential of the synthesized ZnO-Zer NF in cervical cancer cells (HeLa) showed higher cytotoxicity of ZnO-Zer NF (39.32 ± 3.01%) compared to Zer alone (27.02 ± 1.22%). Present study revealing improvement in bioactivity of Zer following conjugation with ZnO NF signifies potential of NF formation in improving therapeutic application of Zer that otherwise displays low solubility limiting its bioavailability.

Effect of OH substitution in 3-benzylchroman-4-ones: crystallographic, CSD, DFT, FTIR, Hirshfeld surface, and energy framework analysis.

3-Benzylchroman-4-ones (homoisoflavanones) are oxygen-containing heterocycles with a sixteen-carbon skeleton. They belong to the class of naturally occurring polyphenolic flavonoids with limited occurrence in nature and possess anti-inflammatory, antibacterial, antihistaminic, antimutagenic, antiviral, and angioprotective properties. Recently, we reported the synthesis and anticancer activity studies of fifteen 3-benzylchroman-4-one molecules, and most of them were proven to be effective against BT549 and HeLa cells. In this work, we report the single-crystal X-ray crystallographic studies of two molecules 3-[(2-hydroxyphenyl)methyl]-3,4-dihydro-2H-1-benzopyran-4-one and 3-[(2,4-dimethoxyphenyl)methyl]-3,4-dihydro-2H-1-benzopyran-4-one. The single crystals were grown using a novel laser-induced crystallization technique. We observed that the 3-benzylchroman-4-one derivative bearing OH substitution at the 2' position adopted different conformation due to formation of dimers through O-H⋯O, and C-H⋯O intermolecular hydrogen bondings. The role of OH substitution in the aforementioned conformational changes was evaluated using density functional theory (DFT), Hirshfeld surface, energy framework and FTIR spectroscopy analysis. In addition, we have carried out a Cambridge Structural Database (CSD) study to understand the conformational changes using five analogue structures. X-ray crystallographic, computational, and spectroscopic studies of 3-benzylchroman-4-ones provided an insight into the role of substitution at benzyl moieties in stabilizing the three-dimensional (3D) structures.

Synthesis of ultra-small Rh nanoparticles congregated over DNA for catalysis and SERS applications.

Exploration of rare earth metals for the Surface Enhanced Raman Scattering (SERS) is greatly preferred to identify probe molecules even at nano molar level. Highly stable Rh nanoparticles (NPs) which are ultra-small size have been prepared within 20 min of reaction time as a colloidal solution using a bio-molecular scaffold DNA and NaBH4 as a reducing agent under room temperature. While keeping metal ion concentration fixed and by making difference in DNA concentration, three different sets of Rh@DNA such as 0.08, 0.085 and 0.09 M were formed as nanochains like structure with varying diameters. The average chain length of Rh NPs for varying concentrations of DNA is ∼98 nm and the Rh particles size is below 5 nm in all the cases. These ultra-small Rh NPs have been utilized for two distinct potential applications such as in catalysis and SERS studies. From the catalysis reaction, reduction of 4-Nitro benzaldehyde to 4-amino benzaldehyde, Rh@DNA (0.08 M) has shown rate constant value of 0.26 min-1 which is highest among other concentrations studied. SERS study revealed that the calculated Enhancement Factor (EF) value was 1.19 × 105 for Rh@DNA (0.08 M) which is highest while compared with other concentrations. Apart from catalysis and SERS, the as-synthesized Rh NPs can find applications in other interdisciplinary fields such as organic catalysis, electro-catalysis and so on in near future.

Leuloplakia - review of a potentially malignant disorder.

Leukoplakias are oral white lesions that have not been diagnosed as any other specific disease. They are grouped under premalignant lesions, now redesignated as potentially malignant disorders. Their significance lies in the fact that they have propensity for malignant transformation at a higher rate when compared to other oral lesions. This article reviews aetiology, epidemiology, clinical characteristics, histopathologic features, malignant potential and treatment of oral leukoplakia.

Effect of cations on condensation of a mesogenic amphiphilic molecule at the air-aqueous electrolyte interface.

We report the interactions of a mesogenic molecule, 4'-octyl-4-biphenyl-carbonitrile (8CB), with some cations (Na(+), Cu(2+), Ni(2+), La(3+) and Al(3+)) dissolved in the aqueous subphase. Surface manometry studies show that the di- (Ni(2+) and Cu(2+)) and trivalent (La(3+)) ions promote condensation in the area per molecule and enhance the stability of the monolayer. This is inferred from the increase in the values of collapse pressure and the compression elastic modulus. The specific ion effect is seen between perchlorate and chloride anions with respect to the Al(3+) cation. The presence of monovalent ions (Na(+)) in the subphase does not influence the isotherm of 8CB. However, in this case, with pH (>6), the isotherm shifts to a higher area per molecule. The excess Gibbs free energy calculated for the 8CB monolayer indicates repulsive interaction for monovalent ions and attractive interaction for multivalent ions in the subphase. Kinetic studies of the monolayer in an ion-enriched subphase have yielded an additional characteristic time constant indicative of reorganization of the monolayer. Ellipsometric adsorption isotherm measurements carried out for representative ions show a reduction in the value of the ellipsometric angle with increasing valency. Our studies indicate that the interaction of ions with the 8CB monolayer at the air-electrolyte interface can be promoted by choosing cations of higher valency and anions of larger size, higher polarizability and chaotropic nature. These factors play an important role and can potentially affect the anchoring transition.