Green synthesis of Piper nigrum copper-based nanoparticles: in silico study and ADMET analysis to assess their antioxidant, antibacterial, and cytotoxic effects

Nanobiotechnology is a popular branch of science that is gaining interest among scientists and researchers as it allows for the green manufacturing of nanoparticles by employing plants as reducing agents. This method is safe, cheap, reproducible, and eco-friendly. In this study, the therapeutic property of Piper nigrum fruit was mixed with the antibacterial activity of metallic copper to produce copper nanoparticles. The synthesis of copper nanoparticles was indicated by a color change from brown to blue. Physical characterization of Piper nigrum copper nanoparticles (PN-CuNPs) was performed using UV-vis spectroscopy, FT-IR, SEM, EDX, XRD, and Zeta analyzer. PN-CuNPs exhibited potential antioxidant, antibacterial, and cytotoxic activities. PN-CuNPs have shown concentration-dependent, enhanced free radical scavenging activity, reaching maximum values of 92%, 90%, and 86% with DPPH, H2O2, and PMA tests, respectively. The antibacterial zone of inhibition of PN-CuNPs was the highest against Staphylococcus aureus (23 mm) and the lowest against Escherichia coli (10 mm). PN-CuNPs showed 80% in vitro cytotoxicity against MCF-7 breast cancer cell lines. Furthermore, more than 50 components of Piper nigrum extract were selected and subjected to in silico molecular docking using the C-Docker protocol in the binding pockets of glutathione reductase, E. coli DNA gyrase topoisomerase II, and epidermal growth factor receptor (EGFR) tyrosine to discover their druggability. Pipercyclobutanamide A (26), pipernigramide F (32), and pipernigramide G (33) scored the highest Gibbs free energy at 50.489, 51.9306, and 58.615 kcal/mol, respectively. The ADMET/TOPKAT analysis confirmed the favorable pharmacokinetics, pharmacodynamics, and toxicity profiles of the three promising compounds. The present in silico analysis helps us to understand the possible mechanisms behind the antioxidant, antibacterial, and cytotoxic activities of CuNPs and recommends them as implicit inhibitors of selected proteins

Preparation of Arabidopsis mesophyll protoplasts with high rates of photosynthesis

A simple and quick method is described for rapid isolation of metabolically active mesophyll protoplasts from leaves of Arabidopsis thaliana. The optimal composition of the digestion medium, period of digestion and stability of protoplast preparation were examined. A large number of protoplasts could be prepared within an hour. The isolated protoplasts were intact, stable and metabolically very active, as indicated by their high rates of photosynthetic oxygen evolution. The important factors during the preparation of protoplasts are short time of digestion, composition of medium, use of nylon nets for filtration, centrifugation at low speed and use of pH 7.0 for storage. The highest rate of photosynthesis obtained in these experiments was 130±4 μmol O<SUB>2</SUB> evolved mg<SUP>−1</SUP> Chl h<SUP>−1</SUP>, at 1 mM sodium bicarbonate and at a light intensity of 600 μE m<SUP>−2</SUP>s<SUP>−1</SUP>. The present technique of isolation can be very useful for making Arabidopsis protoplasts for studies on not only metabolic processes, such as photosynthesis, but also metabolomics, proteomics and genomics

Markedly low requirement of added CO<SUB>2</SUB> for photosynthesis by mesophyll protoplasts of pea (Pisum sativum): possible roles of photorespiratory CO<SUB>2</SUB> and carbonic anhydrase

Mesophyll protoplasts of pea required only 74.1 μM CO2 for maximal photosynthesis, unlike chloroplasts, which required up to 588 μM CO2. Such a markedly low requirement for CO2 could be because of an internal carbon source and/or a CO2 concentrating mechanism in mesophyll protoplasts. Ethoxyzolamide (EZA), an inhibitor of internal carbonic anhydrase (CA) suppressed photosynthesis by mesophyll protoplasts at low CO2 (7.41 μM) but had no significant effect at high CO2 (741 μM). However, acetazolamide, another inhibitor of CA, did not exert as much dramatic effect as EZA. Three photorespiratory inhibitors, aminoacetonitrile or glycine hydroxamate (GHA) or aminooxyacetate inhibited markedly photosynthesis at low CO2 but not at high CO2. Inhibitors of glycolysis or tricarboxylic acid cycle (NaF, sodium malonate) or phosphoenolpyruvate carboxylase (3,3-dichloro-2-dihydroxy phosphinoyl-methyl-2-propenoate) had no significant effect on photosynthesis. The CO2 requirement of protoplast photosynthesis and the sensitivity of photosynthesis to EZA were much higher at low oxygen (65 nmol ml−1) than that at normal oxygen (212 nmol ml−1). In contrast, the inhibitory effect of photorespiratory inhibitors on protoplast photosynthesis was similar in both normal and low oxygen medium. The marked elevation of glycine/serine ratio at low O2 or in presence of GHA confirmed the suppression of photorespiratory decarboxylation by GHA. While demonstrating interesting difference between the response of protoplasts and chloroplasts to CO2, we suggest that photorespiration could be a significant source of CO2 for photosynthesis in mesophyll protoplasts at limiting CO2 and at atmospheric levels of oxygen. Obviously, carbonic anhydrase is essential to concentrate or retain CO2 in mesophyll cells

Ajwa-Dates (<i>Phoenix dactylifera</i>)-Mediated Synthesis of Silver Nanoparticles and Their Anti-Bacterial, Anti-Biofilm, and Cytotoxic Potential

Green nanotechnology is the evolution of cost-effective and environmentally friendly processes for the production of metal-based nanoparticles due to medicinal importance and economic value. The aim of the present study was to biosynthesize and characterize silver nanoparticles (AgNPs) using the seed extract of Ajwa dates (Aw). The anti-bacteriostatic activity of biosynthesized Aw–AgNPs against Gram-positive and Gram-negative bacterial strains was evaluated. The anti-biofilm activity was examined by the tissue culture plate method. Lastly, the anti-cancer potential of Aw–AgNPs was investigated against the human breast cancer cell line HCC712. UV–visible absorption spectra exhibited the plasmon resonance peak at 430 nm, with the solution undergoing rapid color changes that verified the existence of biosynthesized silver nanoparticles in the solution. TEM and SEM images illustrated that the Aw–AgNPs were spherical and between 15 and 80 nm in diameter. The reduction and stabilization of Aw–AgNPs was due to the functional groups present in the biomolecules of the Ajwa seeds, as identified by FTIR. The Aw–AgNPs exhibited significant anti-bacterial activity against all the tested bacterial strains. Moreover, the Aw–AgNPs efficiently hampered the biofilm formation of the bacterial strains and exhibited cytotoxicity at various concentrations. Overall, these findings suggest that biosynthesized Aw–AgNPs may be used as a potential therapeutic formulation against bacterial infections and breast cancer