Lobelia trigona Roxb-based nanomedicine with enhanced biological applications: in vitro and in vivo approach.

This is the first study to report the green synthesis of Lobelia trigona Roxb-mediated silver nanoparticles (LTAgNPs). The optical and structural properties of the synthesised LTAgNPs were analysed using ultraviolet-visible spectroscopy, scanning electron microscopy, Fourier transform infrared, dynamic light scattering and energy dispersive X-ray. LTAgNps were evaluated for their anti-bacterial and anti-fungal properties against 18 pathogens and exhibited significant inhibition against all the strains tested. LTAgNPs had potential scavenging effects on the DPPH, •OH, O2•- free radical scavenging assays and reducing power assay. LTAgNps possess strong anti-cancer activity against five human cancer cell lines (A549, MCF-7, MDA-MB-231, HeLa and KB) in a dose-dependent manner. The antiproliferative, anti-inflammatory and genotoxicity effects of LTAgNPs were further confirmed by the lactate dehydrogenase release assay, nitric oxide inhibitory assay and comet assay. Furthermore, the incision, excision and burn wound-healing activity of formulated LTAgNPs ointment was assessed in rats. All the wounds had significant healing in groups treated with LTAgNPs ointment compared to the groups treated with the commonly prescribed ointment (SilverexTM). This study shows and suggests that the previously unreported LTAgNPs could be used as a nanomedicine with significant biological applications.

Supramolecular complex binding to G-quadruplex DNA: Berberine encapsulated by a planar side arm-tethered ß-cyclodextrin.

G-quadruplex-binders have the plausible potential to act as anticancer agents. Herein, the mode of binding of a synthesized fluorenyl derivative of ß-cyclodextrin with a duplex and G-quadrulex DNAs has been investigated. Moreover, the loading of the well-known G-quadruplex binder, berberine, in the ß-cyclodextrin derivative using 2-dimensional rotating-frame Overhauser effect spectroscopy is studied. The intensity of proton NMR signals is weakened on the ß-cyclodextrin derivative's interaction with the quadruplexes. Binding constants are reported for each binding of the ligands to calf thymus DNA, kit22, telo24, and myc22 employing fluorescence spectroscopy. A general trend of fluorescence response (quenching) on the ß-cyclodextrin derivative to the DNAs is modified when the berberine molecule is loaded in the host structure. Despite berberine binds to the macromolecular target strongly, its host-guest association with the cavity of ß-cyclodextrin diminishes the binding strength. A significant difference between the binding strengths of the ligands with duplex and quadruplex structures is observed. Communicated by Ramaswamy H. Sarma.

Differential Metal Ion Sensing by an Antipyrine Derivative in Aqueous and ß-Cyclodextrin Media: Selectivity Tuning by ß-Cyclodextrin.

ß-Cyclodextrin (ß-CD) is a nontoxic cyclic oligosachcharide that can encapsulate all or part of organic molecules of appropriate size and specific shape through noncovalent interaction. Herein, we report the influence of ß-CD complex formation of an antipyrine derivative on its metal ion sensing behavior. In aqueous solution, the antipyrine shows a turn-on fluorescence sensing of vanadyl ion, and in cyclodextrin medium it senses aluminum ion. The compound shows an unusual fluorescence quenching on binding with ß-cyclodextrin (log KSV = 2.34 ± 0.02). The differential metal ion sensing is due to the partial blocking of the chelating moiety by the cyclodextrin molecule. The structure of the antipyrine-cyclodextrin complex is optimized by two-dimensional rotating-frame Overhauser effect spectroscopy. The binding constant is determined by isothermal titration calorimetry (log K = 2.09 ± 0.004). The metal ion binding site is optimized by quanutm mechanical calculations. The lower limit of detection of vanadyl and aluminum ions, respectively, are 5 × 10-8 and 5 × 10-7 mol dm-3. This is the first report of selectivity of two different cations by a chemosensor in water and in ß-CD.

Picking Out Logic Operations in a Naphthalene ß-Diketone Derivative by Using Molecular Encapsulation, Controlled Protonation, and DNA Binding.

On-off switching and molecular logic in fluorescent molecules are associated with what chemical inputs can do to the structure and dynamics of these molecules. Herein, we report the structure of a naphthalene derivative, the fashion of its binding to ß-cyclodextrin and DNA, and the operation of logic possible using protons, cyclodextrin, and DNA as chemical inputs. The compound crystallizes out in a keto-amine form, with intramolecular N-H⋅⋅⋅O bonding. It shows stepwise formation of 1:1 and 1:2 inclusion complexes with ß-cyclodextrin. The aminopentenone substituents are encapsulated by ß-cyclodextrin, leaving out the naphthalene rings free. The binding constant of the ß-cyclodextrin complex is 512 m(-1). The pKa value of the guest molecule is not greatly affected by the complexation. Dual input logic operations, based on various chemical inputs, lead to the possibility of several molecular logic gates, namely NOR, XOR, NAND, and Buffer. Such chemical inputs on the naphthalene derivative are examples of how variable signal outputs based on binding can be derived, which, in turn, are dependent on the size and shape of the molecule.