Multifunctional Bionanocomposite Films Based on Chitosan/Polyvinyl Alcohol with ZnO NPs and <i>Carissa carandas</i> Extract Anthocyanin for Smart Packaging Materials

The present work describes chitosan (CS) and polyvinyl alcohol (PVA) films incorporated with the natural anthocyanin derived from Carissa carandas and fabricated with ZnO NPs. They showed pH sensitivity, antioxidant activity, and cell viable properties. Anthocyanin, ZnO NPs, and anthocyanin-ZnO NPs fabricated on the CS/PVA matrix significantly increased mechanical resistance and reduced moisture contents (MCs) and water vapor permeability (WVP) of the films significantly. The inclusion of anthocyanin-ZnO NPs significantly affected the cell viability of the prepared film (P > 0.05). Optical characteristics suitable for food packaging applications were exhibited by the prepared films. Additionally, in various pH buffer solutions, the developed films showed noticeable color changes and could be visualized. This property of the film could be employed for fish packaging to monitor freshness, with the film turning from colorless to yellow. It could efficiently monitor the degree of the fish fillet deterioration. Moreover, the prepared CPAZ films showed very good antioxidant activity and cell viability and emerged as a smart intelligent film for food packaging industries

An Agro-Waste Catalyzed Facile Synthesis of 1<i>H-</i>Pyrazolo[1,2-b]Phthalazine-5,10-Dione Derivatives: Evaluation of Antioxidant and Electrochemical Studies

Rapid and inexpensive one-pot multicomponent synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione through a condensation reaction of aryl aldehyde, malononitrile or ethyl cyanoacetate and phthalhydrazide catalyzed by water extract of papaya bark ash (WEPBA) solvent medium under microwave irradiation is described. The catalytic medium is used environmentally friendly, and provides several benefits of being simple, inexpensive, high yield, simple work-up and not required hazardous solvent for the reaction. Some of the selected derivatives were characterized by FT-IR, 1H-, and 13C-NMR, and mass spectrometry techniques. The oxidation-reduction properties of the synthesized compounds (4b, 4e, 4f, 4i, and 4k and 6f, 6g, 6h, 6i, and 6j) were studied using cyclic voltammetry (CV). The voltammetry peak current for the oxidation-reduction of the compounds examined at different scan rates. Further, some of the selected 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives were evaluated in vitro antioxidant activity using DPPH assay method. The result appears that, compounds 4b, 4e, 4i, 6f, 6g, and 6h possess significant antioxidant properties in comparison with the ascorbic acid reference.</p

Disulfide Sensitivity in the Env Protein Underlies Lytic Inactivation of HIV‑1 by Peptide Triazole Thiols

We investigated the mode of action underlying lytic inactivation of HIV-1 virions by peptide triazole thiol (PTT), in particular the relationship between gp120 disulfides and the C-terminal cysteine-SH required for virolysis. Obligate PTT dimer obtained by PTT SH cross-linking and PTTs with serially truncated linkers between pharmacophore isoleucine–ferrocenyltriazole-proline–tryptophan and cysteine-SH were synthesized. PTT variants showed loss of lytic activity but not binding and infection inhibition upon SH blockade. A disproportionate loss of lysis activity vs binding and infection inhibition was observed upon linker truncation. Molecular docking of PTT onto gp120 argued that, with sufficient linker length, the peptide SH could approach and disrupt several alternative gp120 disulfides. Inhibition of lysis by gp120 mAb 2G12, which binds at the base of the V3 loop, as well as disulfide mutational effects, argued that PTT-induced disruption of the gp120 disulfide cluster at the base of the V3 loop is an important step in lytic inactivation of HIV-1. Further, PTT-induced lysis was enhanced after treating virus with reducing agents dithiothreitol and tris (2-carboxyethyl)­phosphine. Overall, the results are consistent with the view that the binding of PTT positions the peptide SH group to interfere with conserved disulfides clustered proximal to the CD4 binding site in gp120, leading to disulfide exchange in gp120 and possibly gp41, rearrangement of the Env spike, and ultimately disruption of the viral membrane. The dependence of lysis activity on thiol–disulfide interaction may be related to intrinsic disulfide exchange susceptibility in gp120 that has been reported previously to play a role in HIV-1 cell infection