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In this study, three Schiff base compounds, (E)‐N‐(4‐bromophenyl)‐1‐(2‐nitrophenyl)methanimine (L1), (E)‐2‐((mesitylimino)methyl)phenol (L2), and (E)‐N‐(4‐bromophenyl)‐1‐(pyridin‐2‐yl)methanimine (L3), were synthesized and characterized by various spectroscopic techniques. The antibacterial activity of the compounds was evaluated against Gram‐positive and Gram‐negative bacteria, with L3 demonstrating the most significant activity. The compounds were also evaluated for their antioxidant activity using DPPH, FRAP, and NO scavenging assays. While the compounds exhibited concentration‐dependent scavenging of free radicals, their activity was not as significant as that of the reference, Trolox. Furthermore, L1–L3 were tested for their α‐amylase and α‐glucosidase inhibitory activity, with L1 showing the highest inhibitory activity among the three compounds. The DFT study showed that L1 is the most chemically reactive among the three compounds, having the lowest energy band gap value of 3.82 eV in acetonitrile, the experimental solvent. Molecular docking predicted that L1 and L2 have very strong inhibition equivalents to the standard drugs against bacteria and diabetes. All the compounds showed stronger inhibition against α‐glucosidase than acarbose, while only L1 and L2 exhibited stronger inhibition against α‐amylase than acarbose. It can be deduced that the theoretical studies corroborate well with the experimental, and compounds with the electron‐withdrawing group displayed better medicinal properties than their electron‐donating counterparts. [ABSTRACT FROM AUTHOR]

The prominent benefit of granite is owned to its physicochemical property and ubiquitous nature. Vast application of granite which also includes its use as an adsorbent in environmental remediation practice, can also be enhanced. To further enhanced the uptake capacity of granite, nanocomposite consisting of multiwall carbon nanotubes (MWCNTs) and granite was fabricated and further modified using Dialiumguineensestem bark extract. The structure and composition of pristine granite (PG) and modified nanocomposite granite (G) based material were examined and confirmed by the FTIR, Raman, TGA, SEM and XRD. Meanwhile, the specific surface areasof PG (1.268 m2/g) and G (16.57 m2/g) were obtained using the BET surface area analyser. The optimization step revealed that the uptake capacities of PG and G were dependent on solution pH, sorbent dose and contact time. Meanwhile, pseudo-second-order and Elovich kinetic models were noticed to best describe the data for the removal of Cr (VI) by PG and G. Equilibrium isotherm study revealed that Freundlich and Langmuir models fitted well to the experimental data obtained for the uptake of Cr(VI) onto PG and G respectively. Furthermore, electrostaticattraction betweentheDialiumguineense stem bark extract on the surface of G and Cr(VI) influenced the uptake of Cr(VI). On the other hand, the interaction between the plant extract and Cr(VI) may result in the attenuation of Cr(VI) via reduction to Cr(III). Finally, the thermodynamically favoured adsorptive process demonstrated high adsorbent reusability with good stability for Cr(VI) uptake. [ABSTRACT FROM AUTHOR]

This study investigates the capacity of spent self-indicating silica gels modified with Harpephyllumcaffrum(wild plum) stem bark extract to remove hexavalent chromium from wastewater. The physicochemical properties of the adsorbents were assessed using FESEM, FTIR, PXRD, TGA and BET surface analyser. The batch adsorption technique was used to examine the capacity of spent self-indicating silica gel (SIPP) and modified spent self-indicating silica gel (SIP) to eliminate Cr(VI) from the aqueous solution. The uptake capacity of the sorbents was noticed to increase with increasing adsorbent dose, contact time and initial concentration of Cr(VI). On the contrary, the potential of SIPP and SIP were observed to decline with increasing solution pH, similarly as found for most Cr(VI) absorbents. However, the uptake capacity of the SIPP and SIP were noticed to be optimum at 0.05 g adsorbent dosage and 180 min contact time. Meanwhile, the kinetic behaviour of SIPP and SIP in the removal of Cr(VI) was best described by the Elovich kinetic model. Furthermore, the uptake of Cr(VI) onto SIP and SIPP was sufficiently described by the three-parameter isotherm Sips and Freundlich isotherms respectively. The Cr(VI) adsorption was endothermic, entropy-driven, and feasible. The application of Harpephyllum caffrumstem bark extract on SIPP as Cr(VI) adsorbent was significant and the reusability of the adsorbent portrayed the capacity of SIP to adapt to a full-scale wastewater treatment practice. [ABSTRACT FROM AUTHOR]

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This study presents the fabrication of nanocomposite for the sequestering of Cr(VI) from solution. The nanocomposites were obtained from the molecular sieve and functionalized multiwall carbon nanotubes and further modified with Pentaclethra macrophylla (oil bean tree) stem bark extract. The pristine molecular sieve (MS) and the modified nanocomposite [Pentaclethra macrophylla stem bark extract anchored on molecular sieve (SMP)] adsorbent were characterized by the FTIR, FESEM, XRD, BET, and TGA techniques. The batch adsorption experiment revealed an agitation time of 120 min, 0.02 g dosage, and sorbate pH of 2.0 as optimum conditions for effective use of MS and SMP. Under these conditions a maximum monolayer capacity (qmax) of 135.5 mg g−1 was obtained for SMP, a value that is better compared to many other related absorbent materials. The uptake of Cr(VI) onto MS and SMP was best described by pseudo-first-order and Elovich kinetic models respectively. Meanwhile, the Freundlich model was noticed to sufficiently describe the isotherm data obtained for MS and SMP. The adsorption of Cr(VI) onto MS and SMP was spontaneous, endothermic, and entropy-driven. The reusability of the nanocomposite and its efficient Cr(VI) removal, present SMP as a potent adsorbent for the sequestration Cr(VI) from aqueous solution. nsufficient innovative research on the sequestration of Cr(VI) from the aquatic ecosystem has made Cr(VI) a recalcitrant water contaminant that often affects water sources. In this work, a novel plant anchor-nanocomposite was fabricated from the spent molecular sieve, multi-walled carbon nanotubes, and the extract from the stem bark of Pentaclethra macrophylla. It was envisaged that due to the phytochemical constituent of the modifier, this nanocomposite could also act as potent adsorbents for the treatment of Cr(VI) polluted water. To the best of our knowledge, the application of Pentaclethra macrophylla stem bark extract as a modifier for the green fabrication of nanocomposite has not been reported. The resulting composites showed good uptake capacity for Cr(VI) as well as efficient reusability. [ABSTRACT FROM AUTHOR]

Three Schiff bases were synthesised by the condensation reaction between 2-napthaldehyde and aromatic amines to afford (E)-N -mesityl-1-(naphthalen-2-yl)methanimine ( L1 ), ( E )- N -(2,6-dimethylphenyl)-1-(naphthalen-2-yl)methanimine ( L2 ) and (E)-N -(2,6-diisopropylphenyl)-1-(naphthalen-2-yl)methanimine ( L3 ). The synthesised compounds were characterised using UV-visible, NMR ( 13 C & 1 H), and Fourier transform infrared spectroscopic methods while their purity was ascertained by elemental analysis. Structural analysis revealed that the naphthalene ring is almost coplanar with the imine functional group as evident by C1-C10-C11-N1 torsion angles of 176.4(2)° and 179.4(1)° in L2 and L3 , respectively. Of all the various intermolecular contacts, H⋯H interactions contributed mostly towards the Hirshfeld surfaces of both L2 (58.7 %) and L3 (69.7 %). Quantum chemical descriptors of L1 - L3 were determined using Density Functional Theory (DFT) and the results obtained showed that the energy band gap (ΔE) for L1 , L2 and L3 are 3.872, 4.023 and 4.004 eV respectively. The antidiabetic potential of the three compounds were studied using α-amylase and α-glucosidase assay. Compound L1 showed very promising antidiabetic activities with IC 50 values of 58.85 μg/mL and 57.60 μg/mL while the reference drug (Acarbose) had 405.84 μg/mL and 35.69 μg/mL for α-amylase and α-glucosidase respectively. In-silico studies showed that L1 docking score as well as binding energies are higher than that of acarbose, which are recognized inhibitors of α-amylase together with α-glucosidase. Further insight from the RMSF, RMSD and RoG analysis predicted that, throughout the simulation L1 showcased evident influence on the structural stability of α-amylase. The antioxidant potential of the compounds was carried out using nitric oxide (NO), ferric reducing ability power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. The compounds exhibited good to fairly antioxidant properties with L1 as well as L3 having IC 50 values of 70.91 and 91.21 μg/mL respectively for NO scavenging activities assay, which comparatively outshined acarbose (reference drug) with IC 50 value of 109.95 μg/mL. Pharmacology and pharmacokinetics approximations of L1 - L3 showed minimal violation of Lipinski's Ro5 and this projects them to be less toxic and orally bioavailable as potential templates for the design of therapeutics with antioxidant and antidiabetic activities., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors. Published by Elsevier Ltd.)