The main protease of SARS-CoV-2 is one of the important targets to design and develop antiviral drugs. In this study, we have selected 40 antiviral phytochemicals to find out the best candidates ...which can act as potent inhibitors against the main protease. Molecular docking is performed using AutoDock Vina and GOLD suite to determine the binding affinities and interactions between the phytochemicals and the main protease. The selected candidates strongly interact with the key Cys145 and His41 residues. To validate the docking interactions, 100 ns molecular dynamics (MD) simulations on the five top-ranked inhibitors including hypericin, cyanidin 3-glucoside, baicalin, glabridin, and α-ketoamide-11r are performed. Principal component analysis (PCA) on the MD simulation discloses that baicalin, cyanidin 3-glucoside, and α-ketoamide-11r have structural similarity with the apo-form of the main protease. These findings are also strongly supported by root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), radius of gyration (Rg), and solvent accessible surface area (SASA) investigations. PCA is also used to find out the quantitative structure-activity relationship (QSAR) for pattern recognition of the best ligands. Multiple linear regression (MLR) of QSAR reveals the R
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value of 0.842 for the training set and 0.753 for the test set. Our proposed MLR model can predict the favorable binding energy compared with the binding energy detected from molecular docking. ADMET analysis demonstrates that these candidates appear to be safer inhibitors. Our comprehensive computational and statistical analysis show that these selected phytochemicals can be used as potential inhibitors against the SARS-CoV-2.
Communicated by Ramaswamy H. Sarma
In the design of greener chemicals, deep eutectic solvents (DESs) are considered as one of the most versatile alternative media with widespread applications. DESs have the advantages of being ...nonflammable with negligible vapor pressure compared to the traditional solvents. They share many characteristics of ionic liquids, but DESs are cheaper to formulate, typically nontoxic, highly pure, recyclable, biodegradable, and are suitable for use with biological systems. In this article, the two emerging and unconventional types of DESs, therapeutic DES (THEDES) and amino acid-based DES (AADES) are reviewed. Based on the published literature, choline chloride and menthol are the two most common constituents to formulate THEDESs, while proline is the most common component to formulate AADESs. THEDESs have primarily been developed to enhance the efficacy of drugs, whereas AADESs have been explored for pharmaceuticals as well as for the extraction of phytochemicals, radioactive iodine capture, oil separation from ores, and to synthesize bioactive compounds. Since detailed knowledge of their structures, nonbonding interactions, formulations, and applications are yet to be explored, the aim of this review is to compile these details and provide a solid background for the future research.
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•Two unconventional and emerging deep eutectic solvents•Therapeutic deep eutectic solvent (THDES) and amino acid-based deep eutectic solvent (AADES)•Formulation, molar ratios, structural insights, and applications•THDES are mainly developed for pharmaceuticals•AADES have been explored for pharmaceuticals, for the extraction of value-added compounds, and as media for green synthesis.
A molecular docking approach was employed to evaluate the binding affinity of six triterpenes, namely epifriedelanol, friedelin, α-amyrin, α-amyrin acetate, β-amyrin acetate, and bauerenyl acetate, ...towards the cannabinoid type 1 receptor (CB1). Molecular docking studies showed that friedelin, α-amyrin, and epifriedelanol had the strongest binding affinity towards CB1. Molecular dynamics simulation studies revealed that friedelin and α-amyrin engaged in stable non-bonding interactions by binding to a pocket close to the active site on the surface of the CB1 target protein. The studied triterpenes showed a good capacity to penetrate the blood-brain barrier. These results help to provide some evidence to justify, at least in part, the previously reported antinociceptive and sedative properties of
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Water, sanitation, and hygiene interventions have varying effectiveness in reducing fecal contamination in the domestic environment; delivering them in combination could yield synergies. We conducted ...environmental assessments within a randomized controlled trial in Bangladesh that implemented single and combined water treatment, sanitation, handwashing (WSH) and nutrition interventions (WASH Benefits, NCT01590095). After one and two years of intervention, we quantified fecal indicator bacteria in samples of drinking water (from source or storage), child hands, children’s food and sentinel objects. In households receiving single water treatment interventions, Escherichia coli prevalence in stored drinking water was reduced by 50% and concentration by 1-log. E. coli prevalence in food was reduced by 30% and concentration by 0.5-log in households receiving single water treatment and handwashing interventions. Combined WSH did not reduce fecal contamination more effectively than its components. Interventions did not reduce E. coli in groundwater, on child hands and on objects. These findings suggest that WSH improvements reduced contamination along the direct transmission pathways of stored water and food but not along indirect upstream pathways. Our findings support implementing water treatment and handwashing to reduce fecal exposure through water and food but provide no evidence that combining interventions further reduces exposure.
Due to the increased and excessive consumption of fossil fuels, sustainable alternative energy sources are badly needed to replace fossil fuels. The conversion of biomass into energy and value-added ...chemicals is one of the most promising potential pathways to solve this problem. Millions of tons of lignin, one of the major components of biomass, are produced annually as a byproduct of various industries, where it is treated as a low-value material. However, since it has an aromatic polymer nature, lignin is a proven source for different value-added products. Studies suggest that the selective cleavage of a specific bond of the complex lignin structure is one of the major challenges of converting lignin to a targeted product. In this study, eight different lignin depolymerization methods, both traditional and green, are reviewed. Acid and base catalytic depolymerization methods are straightforward, but due to their low selectivity and comparatively severe reaction conditions, they are expensive and not eco-friendly. Pyrolysis-based depolymerization comes with similar problems but has a higher conversion. In contrast, greener approaches, such as oxidative, microwave-assisted, super/sub-critical fluids (SCF), ionic liquid (IL), and deep eutectic solvent (DES)-based depolymerization techniques, have shown higher efficiency in terms of converting the lignin into phenolic compounds even under milder reaction conditions. SCF, IL, and DES-based approaches will likely become more popular in the future for their greener nature. Overall, depolymerization of lignin with greener technologies could make this process more economically viable and sustainable.
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•Experimental Raman and IR spectroscopy proved the formation of ChCl-water DESs.•Computed Raman and IR showed good degree of agreement with the experimental data.•Computed nonbonding ...interactions and radial distribution function calculations visualize the DES nanostructures.•Solubility of drugs and efficient drug delivery could be possible by these solvents.•Viscosity, density, conductivity, and pH of the DESs added more insights.
In this study, experimental and computed IR and Raman spectroscopic techniques helped to prove how water as a sole hydrogen bond donor (HBD) participates to form a deep eutectic solvent. Interactions among the components and contributions of the water and chloride have been successfully illustrated by quantum chemical (QC) and radial distribution function (RDF) calculations. These studies suggested that the spontaneous intercalation of water molecules with choline chloride (ChCl) helps to attain the stable cluster structure, where Cl- works as a bridge among the Ch+ and water molecules. Hydrogen bonds played major roles to form the water-based DESs. Solubilities of the studied drug molecules were found to be 1.3 to 6.7 times higher in the solvents than their solubilities in water. Cell viability assay of the WDES1 (1:3 ChCl:H2O) compared to dimethyl sulfoxide (DMSO) against HEK293 cell line proved that the solvent is applicable to the biological system. The RDF analysis from MD simulation suggest the spontaneous intercalation of water molecule in Choline Chloride structure disrupted the ordered structure as well as the Cl-, working as bridge in between Ch+ and water.
Adsorption is one of the best techniques to mitigate industrial dye pollution. In this study, surface of the Mg–Al layered double hydroxide (LDH) was modified with graphene oxide (GO) to improve its ...adsorption efficacy of Eriochrome Black T (EBT) dye molecules. A higher correlation coefficient value of the Langmuir adsorption model indicated monolayer adsorption of EBT at the active sites of Mg–Al LDH. The optimum adsorption potential was obtained around 0.4 and 1.4 mmol of EBT per g of the LDH and the modified LDH, respectively, and both adsorbents followed pseudo-second-order kinetics. Molecular dynamics study revealed that both GO and LDH contribute to adsorb EBT. Hydrogen bonds, such as C-H…O, O–H…N, O–H…O = S, O–H…N, and N = O…H–O-Al are the major contributing forces behind the adsorption. Besides, π…alkyl, Mg…O = S, π…cation, π…anion, π…donor, π…sigma, and π…lone pair of interactions are the additional contributing forces behind the enhancement of the efficacy of the modified composite.
Lignocellulosic biomass is a renewable resource that contains three major constituents: cellulose, hemicellulose, and lignin. Lignin is a potential source of aromatic phenols. The extraction and ...subsequent depolymerization of lignin was studied using pine sawdust and pistachio shells. Lignin extraction used 70:30 methyl isobutyl ketone:ethanol followed by 0.1M H2SO4. The extraction yield of lignin was 15.78 ± 3.38% from pistachio shells and 18.86 ± 1.52% from pine sawdust. The extracted lignin was characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and 1H-NMR spectroscopy. The extracted lignin was depolymerized using subcritical water and a Ni-Graphene catalyst at 240 °C for 10 min. The depolymerization products were identified as phenolic monomers, such as phenol, guaiacol, vanillin, syringol, guaiacylpropane, syringaldehyde, coniferaldehyde, synapyl alcohol, and synapyl aldehyde, using GC-MS.
We conducted a cross sectional study to assess 1) the association between access to basic sanitation and fecal contamination of sentinel toy balls and 2) if other sanitation factors such as shared ...use and cleanliness are associated with fecal contamination of sentinel toy balls. We assessed sanitation facilities in 454 households with a child aged 6-24 months in rural Bangladesh. We defined "basic" sanitation as access to improved sanitation facilities (pit latrine with a slab or better) not shared with other households. In each household, an identical toy ball was given to the target child. After 24 hours, the balls were rinsed to enumerate fecal coliforms as an indicator of household fecal contamination. Households with basic sanitation had lower fecal coliform contamination than households with no access to basic sanitation (adjusted difference in means: -0.31 log
colony forming units CFU/toy ball; 95% confidence interval CI: -0.61, -0.01). Shared sanitation facilities of otherwise improved type were more likely to have visible feces on the latrine slab compared with private facilities. Among households with access to improved sanitation, households with no visible feces on the latrine slab had less toy ball contamination than households with visible feces on the latrine slab (adjusted difference in means: -0.38 log
CFU/toy ball; 95% CI: -0.77, 0.02). Access to basic sanitation may prevent fecal contamination of the household environment. An Improved sanitation facility used by an individual household may be better in preventing household fecal contamination compared with improved facilities shared with other households.
The successful conversion of lignocellulose into value-added products depends on overcoming the recalcitrance of its structure towards enzymatic digestion. The highly crosslinked structure of lignin, ...crystallinity of cellulose, and low digestibility of hemicellulose create the recalcitrance. Many studies have proved that an appropriate pretreatment method could enhance the digestibility of lignocellulosic biomass by weakening the strong network of its chemical bonds among the cellulose, hemicellulose, and lignin. There are several conventional ways to separate the components from each other, but the requirements of high temperature and pressure, use of strong acids and bases, and expensive instrumentation make the pretreatment methods difficult to use. Greener solvents, e.g. supercritical fluid, ionic liquid, and deep eutectic solvent (DES)-based pretreatment techniques can overcome the difficulties. Although a lot of pilot scale and rigorous studies are required to launch the greener technologies commercially, they have already shown a lot of promise in the field of biomass pretreatments. Among the greener solvents, DESs are cheaper, easily recyclable, environmentally benign, and the efficiency of the DES-based pretreatment can be enhanced manifold by applying microwave and ultrasound. Therefore, DES-based pretreatment could be one of the most popular techniques in the future.
•Successful conversion of lignocellulose into value-added products requires efficient pretreatment.•Pretreatment reduces the structural stiffness of lignocellulose.•Conventional pretreatment technologies are not green and sustainable.•Supercritical fluid, ionic liquid, and deep eutectic solvent-based pretreatments are greener, efficient, cheaper, eco-friendly technologies.•Understanding the mechanisms of the greener pretreatments and the structural insights of the lignocellulose could help to make the technologies more efficient and sustainable.
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