Synthesis and in silico investigation of organoselenium-clubbed Schiff bases as potential mpro inhibitors for the SARS-CoV-2 replication

Since the first report of the organoselenium compound, ebselen, as a potent inhibitor of the SARS-CoV-2 Mpro main protease by Z. Jin et al. (Nature, 2020), different OSe analogs have been developed and evaluated for their anti-COVID-19 activities. Herein, organoselenium-clubbed Schiff bases were synthesized in good yields (up to 87%) and characterized using different spectroscopic techniques. Their geometries were studied by DFT using the B3LYP/6–311 (d, p) approach. Ten FDA-approved drugs targeting COVID-19 were used as model pharmacophores to interpret the binding requirements of COVID-19 inhibitors. The antiviral efficiency of the novel organoselenium compounds was assessed by molecular docking against the 6LU7 protein to investigate their possible interactions. Our results showed that the COVID-19 primary protease bound to organoselenium ligands with high binding energy scores ranging from −8.19 to −7.33 Kcal/mol for 4c and 4a to −6.10 to −6.20 Kcal/mol for 6b and 6a. Furthermore, the docking data showed that 4c and 4a are good Mpro inhibitors. Moreover, the drug-likeness studies, including Lipinski’s rule and ADMET properties, were also assessed. Interestingly, the organoselenium candidates manifested solid pharmacokinetic qualities in the ADMET studies. Overall, the results demonstrated that the organoselenium-based Schiff bases might serve as possible drugs for the COVID-19 epidemic

Ballota saxatilis from Jordan: Evaluation of Essential Oil Composition and Phytochemical Profiling of Crude Extracts and Their In-Vitro Antioxidant Activity

The chemical composition of essential oil extracted from the aerial parts of Ballota saxatilis Sieber ex C.Presl from Jordan has been elucidated by gas chromatography–mass spectrometry (GC-MS). Additionally, aqueous methanol (BsA), Butanol (BsB) and water (BsW) extracts were screened for their total phenol content (TPC), total flavonoid content (TFC), and antioxidant activities using the 2,2 Diphenyl-1-picrylhydrazyl (DPPH) and 2,2-Azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) diammonium salt (ABTS) methods. The most potent extracts were screened for their phenolic acids and flavonoid content using liquid the chromatography–mass spectrometry (LC-MS) technique. The results indicated that the essential oil predominantly contained cis-pinane (14.76%), β-caryophyllene (8.91%) and allo-aromadendrene epoxide (6.39%). Among the different extracts investigated, the BsB fraction had the most TPC and TFC (455.79 ± 1.03 µg gallic acid/g dry extract; 272.62 ± 8.28 µg quercetin/g dry extract, respectively) and had the best radical and radical cation scavenging activities, as determined using the DPPH and ABTS methods. Quantitative and qualitative LC-MS analyses of BsA and BsB using LC-MS revealed each of the kaempferol-3-O-rutinoside (30.29%), chrysoeriol-7-glucoside (7.93%) and luteolin 7-o-glucoside (7.76%) as the main constituents of the BsA fraction. The BsB fraction was rich in 7,4′-dimethoxy-3-hydroxyflavone (34.68%), kaempferol-3,7,4′-trimethyl ether (29.17%) and corymbosin (9.66%) and lower concentration levels of kaempferol-3-O-rutinoside (1.63%) and chrysoeriol-7-glucoside (0.51%)

Cytotoxicity, Antioxidant Activity and Phytochemical Screening of Four <i>Euphorbia</i> Species from Jordan

The current study was designed to reveal the main groups of secondary metabolites in the methanol (M) and acetone (A) extracts from four Euphorbia species from Jordan. The extracts of these species were also tested for their total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and cytotoxic effects against human MDA-MB-231 cancer cells. Different groups of secondary metabolites were found in the M and A extracts of E. hierosolymitana, E. aleppica, E. petiolata, and E. prostrata. All extracts had moderately high TPC and TFC. Of all species, both extracts of E. aleppica had an exceptionally high TFC that far exceeded its content in all other extracts (1462.67 ± 0.04; 1600.44 ± 0.03 mg quercetin equivalents/g of extract, respectively). E. prostrata extracts had high amounts of TPC (182.61 ± 0.12; 187.35 ± 0.07 mg gallic acid equivalents/g extract) and TFC (629.78 ± 0.00; 774.22 ± 0.01 mg quercetin/g extract). Extracts obtained from the tested Euphorbia species had moderate high antioxidant activity, but the DPPH and ABTS-scavenging activity of the E. prostrata extracts was the highest, but were lower than those observed for the the positive controls (range 0.004–0.009 mg/mL). The methanol extract of E. hierosolymitana also showed strong DPPH scavenging activity (0.007 ± 0.002 mg/mL). The acetone extract of E. prostrata showed much stronger anticancer activity than the positive control drug, doxorubicin (62.5±3.71 mg/mL), against the human breast cancer MDA-MB-231 (HTB-26TM) cell line (IC50 value: 58 ± 3.71 µg/mL)

PREPARATION OF CELLULOSE NANOCRYSTALS FROM DATE PALM TREE LEAFLETS (PHOENIX DACTYLIFERA L.) VIA REPEATED CHEMICAL TREATMENTS

Recently, there has been significant research interest in nanocellulose due to its unique properties and performance. Its special characteristics make it a desirable material for many advanced industrial applications. It is considered a precursor for many industrial products, such as textiles and leather, as well as for some smart applications, such as in the biomedical area, in photonics, and flexible optoelectronics. The preparation of the nanocellulose from bio-based degradable by-products is a great advantage from sustainability and environmental considerations. This work aimed to find the best utilization for locally available date palm tree by-products, in an attempt to turn them into a valuable material. We succeeded in preparing nanocellulose with considerable crystallinity from biomass by-products via chemical and physical processing. The properties of the obtained nanocellulose were investigated using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). It was found that the sonication process (20 kHz, 10 min, 100 C) has a significant role to play in the nanocellulose formation. The nanocellulose was found to have a smaller diameter (20-508 nm) and smoother surface, compared to the untreated fibers, and reached the degradation temperature of 1560 C as a result of the removal of lignin and hemicelluloses. Therefore, cellulose nanocrystals (CNCs) were achieved from low-cost by-products and could be further applied as a biodegradable matrix material.</jats:p

Density Functional Theory and Molecular Docking Investigations of the Chemical and Antibacterial Activities for 1-(4-Hydroxyphenyl)-3-phenylprop-2-en-1-one

The present investigation informs a descriptive study of 1-(4-Hydroxyphenyl) -3-phenylprop-2-en-1-one compound, by using density functional theory at B3LYP method with 6-311G** basis set. The oxygen atoms and π-system revealed a high chemical reactivity for the title compound as electron donor spots and active sites for an electrophilic attack. Quantum chemical parameters such as hardness (η), softness (S), electronegativity (χ), and electrophilicity (ω) were yielded as descriptors for the molecule’s chemical behavior. The optimized molecular structure was obtained, and the experimental data were matched with geometrical analysis values describing the molecule’s stable structure. The computed FT-IR and Raman vibrational frequencies were in good agreement with those observed experimentally. In a molecular docking study, the inhibitory potential of the studied molecule was evaluated against the penicillin-binding proteins of Staphylococcus aureus bacteria. The carbonyl group in the molecule was shown to play a significant role in antibacterial activity, four bonds were formed by the carbonyl group with the key protein of the bacteria (three favorable hydrogen bonds plus one van der Waals bond) out of six interactions. The strong antibacterial activity was also indicated by the calculated high binding energy (−7.40 kcal/mol)

Density Functional Theory and Molecular Docking Investigations of the Chemical and Antibacterial Activities for 1-(4-Hydroxyphenyl)-3-phenylprop-2-en-1-one

The present investigation informs a descriptive study of 1-(4-Hydroxyphenyl) -3-phenylprop-2-en-1-one compound, by using density functional theory at B3LYP method with 6-311G** basis set. The oxygen atoms and π-system revealed a high chemical reactivity for the title compound as electron donor spots and active sites for an electrophilic attack. Quantum chemical parameters such as hardness (η), softness (S), electronegativity (χ), and electrophilicity (ω) were yielded as descriptors for the molecule’s chemical behavior. The optimized molecular structure was obtained, and the experimental data were matched with geometrical analysis values describing the molecule’s stable structure. The computed FT-IR and Raman vibrational frequencies were in good agreement with those observed experimentally. In a molecular docking study, the inhibitory potential of the studied molecule was evaluated against the penicillin-binding proteins of Staphylococcus aureus bacteria. The carbonyl group in the molecule was shown to play a significant role in antibacterial activity, four bonds were formed by the carbonyl group with the key protein of the bacteria (three favorable hydrogen bonds plus one van der Waals bond) out of six interactions. The strong antibacterial activity was also indicated by the calculated high binding energy (−7.40 kcal/mol).</jats:p

Sodium Alginate–Aldehyde Cellulose Nanocrystal Composite Hydrogel for Doxycycline and Other Tetracycline Removal

A novel composite hydrogel bead composed of sodium alginate (SA) and aldehyde cellulose nanocrystal (DCNC) was developed for antibiotic remediation through a one-step cross-linking process in a calcium chloride bath. Structural and physical properties of the hydrogel bead, with varying composition ratios, were analyzed using techniques such as BET analysis, SEM imaging, tensile testing, and rheology measurement. The optimal composition ratio was found to be 40% (SA) and 60% (DCNC) by weight. The performance of the SA–DCNC hydrogel bead for antibiotic remediation was evaluated using doxycycline (DOXY) and three other tetracyclines in both single- and multidrug systems, yielding a maximum adsorption capacity of 421.5 mg g−1 at pH 7 and 649.9 mg g−1 at pH 11 for DOXY. The adsorption mechanisms were investigated through adsorption studies focusing on the effects of contact time, pH, concentration, and competitive contaminants, along with X-ray photoelectron spectroscopy analysis of samples. The adsorption of DOXY was confirmed to be the synergetic effects of chemical reaction, electrostatic interaction, hydrogen bonding, and pore diffusion/surface deposition. The SA–DCNC composite hydrogel demonstrated high reusability, with more than 80% of its adsorption efficiency remaining after five cycles of the adsorption–desorption test. The SA–DCNC composite hydrogel bead could be a promising biomaterial for future antibiotic remediation applications in both pilot and industrial scales because of its high adsorption efficiency and ease of recycling

Effective Thallium(I) Removal by Nanocellulose Bioadsorbent Prepared by Nitro-Oxidation of Sorghum Stalks

Thallium(I) (Tl(I)) pollution has become a pressing environmental issue due to its harmful effect on human health and aquatic life. Effective technology to remove Tl(I) ions from drinking water can offer immediate societal benefits especially in the developing countries. In this study, a bio-adsorbent system based on nitro-oxidized nanocellulose (NOCNF) extracted from sorghum stalks was shown to be a highly effective Tl(I) removal medium. The nitro-oxidation process (NOP) is an energy-efficient, zero-waste approach that can extract nanocellulose from any lignocellulosic feedstock, where the effluent can be neutralized directly into a fertilizer without the need for post-treatment. The demonstrated NOCNF adsorbent exhibited high Tl(I) removal efficiency (&gt;90% at concentration &lt; 500 ppm) and high maximum removal capacity (Qm = 1898 mg/g using the Langmuir model). The Tl(I) adsorption mechanism by NOCNF was investigated by thorough characterization of NOCNF-Tl floc samples using spectroscopic (FTIR), diffraction (WAXD), microscopic (SEM, TEM, and AFM) and zeta-potential techniques. The results indicate that adsorption occurs mainly due to electrostatic attraction between cationic Tl(I) ions and anionic carboxylate groups on NOCNF, where the adsorbed Tl(I) sites become nuclei for the growth of thallium oxide nanocrystals at high Tl(I) concentrations. The mineralization process enhances the Tl(I) removal efficiency, and the mechanism is consistent with the isotherm data analysis using the Freundlich model