Inflammatory Studies of Dehydroandrographolide: Isolation, Spectroscopy, Biological Activity, and Theoretical Modeling

Dehydroandrographolide (DA) was isolated and experimentally characterized utilizing FT-IR, UV-Vis, and NMR spectroscopy techniques along with detailed theoretical modelled at the DFT/B3LYP-D3BJ/6-311 + + G(d,p) level of theory. Substantially, molecular electronic property investigations in the gaseous phase alongside five different solvents (ethanol, methanol, water, acetonitrile and DMSO) were comprehensively reported and compared with the experimental results. The globally harmonized scale (GHS), which is used to identify and label chemicals, was also utilized to demonstrate that the lead compound predicted an LD50 of 1190 mg/kg. This finding implies that consumers can safely consume the lead molecule. Notable impacts on hepatotoxicity, cytotoxicity, mutagenicity, and carcinogenicity were likewise found to be minimal to nonexistent for the compound. Additionally, in order to account for the biological performance of the studied compound, in-silico molecular docking simulation analysis was examined against different anti-inflammatory target of enzymes (3PGH, 4COX, and 6COX). From the examination, it can be inferred that DA@3PGH, DA@4COX, and DA@6COX, respectively, showed significant negative binding affinities of -7.2 kcal/mol, -8.0 kcal/mol, and - 6.9 kcal/mol. Thus, the high mean binding affinity in contrast to conventional drugs further reinforces these results as an anti-inflammatory agent.

Investigation on the molecular, electronic and spectroscopic properties of rosmarinic acid: an intuition from an experimental and computational perspective

Various drugs such as corticosteroids, salbutamol, and β2 agonist are available for the treatment of asthma an inflammatory disease and its symptoms, although the ingredient and the mode of action of these drugs are not clearly elucidated. Hence this research aimed at carrying out improved scientific research with respect to the use of natural product rosmarinic acid which poses minima, side effects. Herein, we first carried out extraction, isolation, and spectroscopic (FT-IR, 1H-NMR and 13C-NMR) investigation, followed by molecular modeling analysis on the naturally occurring rosmarinic acid extracted from Rosmarinus officinalis. A detailed comparison of the experimental and theoretical vibrational analysis has been carried out using five DFT functionals: BHANDH, HSEH1PBE, M06-2X, MPW3PBE and THCTHHYB with the basis set 6-311++G (d, p) to investigate into the structural, reactivity, and stability of the isolated compound. Frontier molecular orbital analysis and appropriate quantum descriptors were calculated. Results showed that the compound was more stable at M06-2X and more reactive at HSEH1PBE with an energy gap of 6.43441 eV and 3.8047 eV, respectively, which was later affirmed by the global quantum reactivity parameters. From natural bond orbital analysis, π* → π* is the major contributor to electron transition with the summation perturbation energy of 889.57 kcal/mol, while π → π* had the perturbation energy totaling of 145.3 kcal/mol. Geometry analysis shows BHANDH to have lower bond length values and lesser deviation from 120° in carbon-carbon angle. The potency of the title molecule as an asthma drug was tested via a molecular docking approach and the binding score of -8.2 kcal/mol was observed against -7.0 of salbutamol standard drug, suggesting romarinic acid as a potential natural organic treatment for asthma.Communicated by Ramaswamy H. Sarma.

Production and performance evaluation of biodiesel from Elaeis guineensis using natural snail shell-based heterogeneous catalyst: kinetics, modeling and optimisation by artificial neural network

This study presents an approach to produce biodiesel from Elaeis guineensis using natural heterogeneous catalysts derived from raw, calcined, and acid-activated forms of waste snail shells. The catalysts were thoroughly characterized using SEM, and process parameters were systematically evaluated during biodiesel production. Our results demonstrate a remarkable crop oil yield of 58.87%, with kinetic studies confirming second-order kinetics and activation energies of 43.70 kJ mol^-1 and 45.70 kJ mol^-1 for methylation and ethylation, respectively. SEM analysis identified the calcined catalyst as the most effective, exhibiting remarkable reusability for continuous reactions running up to five times. Moreover, the acid concentration from exhaust fumes yielded a low acid value (B100 0.0012 g dm^-3), significantly lower than that of petroleum diesel, while the fuel properties and blends satisfied the ASTM standards. The sample-heavy metals were well within acceptable limits, confirming the quality and safety of the final product. Our modelling and optimization approach produced a remarkably low mean squared error (MSE) and a high coefficient of determination (R), providing strong evidence for the viability of this approach at an industrial scale. Our results represent a significant input in sustainable biodiesel production and underscore the enormous potential of natural heterogeneous catalysts derived from waste snail shells for achieving sustainable and environmentally friendly biodiesel production.

Renewable energy as a source of electricity for Murzuq health clinic during COVID-19

Abstract

A great number of populations of the world, primarily in developing countries, are living in rural areas and are commonly isolated from the grid connection. Unstable power supply and increasing energy prices have significant effects on developing countries, especially during this COVID-19 pandemic. Renewable energy sources can provide sustainable and efficient electricity supply. Murzuq is a rural community situated in the southern part of Libya and endowed with renewable energy resources. While there is high electricity consumption during the lockdown, health clinics also experienced higher energy consumption of longer operating hours and an increased number of electrical appliances. This study investigates the techno-economic assessment of three different hybrid energy systems for health clinics in Murzuq. HOMER (Hybrid optimization model for electric renewables) software tool was used to evaluate the feasibility of employing renewable energy, to provide sustainable energy supply to the clinic. The current unsteady energy supply comes from the national grid and the current energy supply is not sufficient for the clinic's operating hours and requires a sustainable and steady supply. Measured data collected from the health clinic and HOMER software were used to analyze and optimize the change in overall electricity demand for the health clinic before and during the COVID-19 pandemic. The results showed that the photovoltaic/battery hybrid energy system has a lower net present cost, compared to the Photovoltaic/Generator set/ battery hybrid energy system, but higher than the standalone generator set. However, the highest amount of carbon emission associated with the standalone generator set compared to the other two hybrid energy systems disqualifies it from being a suitable contender for the source of electricity for the health clinic. The photovoltaic/battery was deemed to be most economically beneficial in terms of emission reduction and energy price. The outcomes of this investigation will help stakeholders and designers to optimize hybrid energy systems that economically meet the health clinic energy demands, especially during this pandemic.

Graphical abstract

Influence of fluorinated graphene-modified epoxy coatings on the corrosion behaviour of 2024 aluminium alloy

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix. FG with different fluorine contents was obtained by reacting nitrogen trifluoride (NF₃) gas with GO and then incorporated into the EP matrix to fabricate the different composites. Through a series of characterization methods, the chemical composition and microstructures of FG were systematically analyzed, and its corrosion resistance was also studied. Results revealed that F atoms were bonded to the GO surface to form C–F covalent bonds, and an FG lamellar thickness less than 2 nm. The contact angle of the coatings increased with the incorporation of FG, and the coating resistance of FG2/EP coating was 3 orders of magnitude more than that of the EP coating after immersion for 4080 h. Thus, the incorporation of FG into epoxy matrix significantly enhanced its hydrophobic properties and barrier performance, which was beneficial to improving the long-term corrosion resistance of the coating.

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix.

Anticorrosion and dispersive adsorption studies of natural andrographolide on carbon steel in acid-chloride environments

Andrographolide, a bioactive naturally occurring labdane diterpenoid with outstanding antioxidant effects in medicine, has been isolated and purified from Andrographis paniculata, and applied in acid-chloride environments for the corrosion protection of carbon steel. Upon isolation, the phytochemical was identified by NMR and FTIR, while its corrosion inhibition evaluation was achieved by combined electrochemical and gravimetric experiments. The adsorption of andrographolide on carbon steel was examined by SEM, FTIR, and 3D surface measurement, and computational studies were used to describe the adsorption characteristics and properties. The experimental measurements revealed that andrographolide is an effective mixed-type corrosion inhibitor whose efficiency was dependent on both its concentration and the temperature of the environment, with maximum inhibition efficiency of 92.4% recorded for 2.0 g/L andrographolide after 48 h at 318 K. The adsorption of andrographolide and its anticorrosion capacity on carbon steel surface was confirmed by the employed surface analytical techniques, while molecular electrostatic potential, conceptual density functional theory, and molecular dynamics simulation predicted the quantum chemical details and binding properties of the phytochemical on Fe (110) surface at different temperatures.

Metolazone compound as corrosion inhibitor for API 5L X-52 steel in hydrochloric acid solution

The aim of this research is to evaluate the inhibitive effect of metolazone on API 5L X-52 steel in 2 M HCl solution using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization techniques within a temperature range of 303 to 323 K. Scanning electron microscopy (SEM) was also employed to study the morphology of the corroded coupons in 2 M HCl solution and in the presence of the inhibitor. The efficiency of the inhibition depends on the concentration of metolazone and reaction system temperature. The maximum inhibition efficiency values were 92.7 and 90.7%, respectively, for both EIS and polarization techniques at the temperature of 303 K. The electrochemical impedance spectra (EIS) studies reveal that the process of inhibition is through charge transfer. Potentiodynamic polarization (PDP) studies showed that metolazone is mixed-type inhibitor.  The metolazone adsorption characteristics on API 5L X-52 steel surface was found to be spontaneous and obeyed Langmuir adsorption isotherm and the mechanism of adsorption suggest chemisorptions. The inhibition efficiency of metolazone drug obtained by electrochemical methods was in good relationship with each other.                     KEY WORDS: Metolazone drug, API 5L X-52 Steel, SEM, Electrochemical, Corrosion inhibition   Bull. Chem. Soc. Ethiop. 2020, 34(2), 407-418 DOI: https://dx.doi.org/10.4314/bcse.v34i2.16