Development of a Fast Simultaneous Analysis Method for Determination of Middle Rare-Earth Elements in Monazite Samples

Rare earth elements are a set of seventeen metallic elements, which is an essential part of many high-tech devices. Hence, analysis and/or separation of the rare earth elements from their mineral become crucial. A novel analysis method combining ultraviolet-visible spectroscopic and multivariate analysis was developed to determine middle rare earth elements quickly and simultaneously. The data collected from ultraviolet-visible spectroscopic were analyzed by multivariate analysis. The results showed that the developed method has good accuracy and precision with a detection limit of 1.375 (± 0.012), 0.332 (± 0.004), 42.117 (± 0.200), 1.767 (± 0.011), and 0.576 (± 0.002) ppm, respectively for samarium, europium, gadolinium, terbium, and dysprosium. The interference effect of ammonium iron(II) sulfate hexahydrate, manganese(III) sulfate hydrate, calcium carbonate, sodium carbonate, and lead(II) nitrate were examined. The reliability of the proposed method was evaluated using monazite samples. Conclusively, the developed method was successfully applied to determine the middle rare earth elements in monazite samples.

Natural Compounds Activities against SARS-CoV-2 Mpro through Bioinformatics Approaches for Development of Antivirus Candidates

Coronavirus infection (COVID-19) caused by SARS-CoV-2 appears as a pandemic that has spread to almost all countries in the world. Antiviral therapy using natural compounds is one alternative approach to overcome this infectious disease. The therapeutic mechanism is proven effective against the main protease (Mpro) of SARS-CoV-2. This research aims to perform bioinformatics studies, including ligand-docking simulations and protein-protein docking simulations, to identify, evaluate, and explore five compounds' activity on SARS-CoV-2 Mpro and their effects against Angiotensin-Converting Enzyme 2 (ACE-2). Protein-ligand docking simulations show kaempferol, flavonol, and their glycosides (Afzelin and Juglanin) and other flavonoids (Quercetin, Naringenin, and Genistein) have a high affinity towards SARS-CoV-2 Mpro. These results were then confirmed using protein-protein docking simulations to observe the ability of five compounds to prevent the attachment of ACE-2 to the active site. Based on the results of the bioinformatics studies, Quercetin has the best affinity, with a binding free energy value of −33.18 kJ/mol. The five compounds are predicted to be able to interact strongly with SARS-CoV-2. The results in this research are useful for further studies in the development of novel anti-infective drugs for COVID-19 that target SARS-CoV-2 Mpro.

Molecular Cloning and Expression of Haloacid Dehalogenase Gene from a Local Pseudomonas aeruginosa ITB1 Strain and Tertiary Structure Prediction of the Produced Enzyme

Organohalogens are widely utilized as pesticides, herbicides, solvents, and for many other industrial purposes. However, the use of these compounds caused some negative impacts to the environment due to their toxicity and persistency. In the light of this, some microbes have been identified and employed to perform dehalogenation, converting halogenated organic compounds to non-toxic materials. In this research, we successfully cloned and sequenced the haloacid dehalogenase gene from a local Pseudomonas aeruginosa ITB1 strain, which is involved in the degradation of monochloroacetate. First, the haloacid dehalogenase gene was amplified by PCR using a pair of primers designed from the same gene sequences of other P. aeruginosa strains available in the GenBank. The cloned gene in pGEM-T in E. coli TOP10 was sequenced, analyzed, and then sub-cloned into pET-30a(+) for expression in E. coli BL21 (DE3). To facilitate direct sub-cloning, restriction sequences of EcoRI (G/AATTC) and HindIII (A/AGCTT) were added to the forward and reversed primers, respectively. The expressed protein in E. coli BL21 (DE3) appeared as a 26-kDa protein in SDS-PAGE analysis, which is in good agreement with the size predicted by ExPASy Protparam. We obtained that the best expression in LB liquid medium was achieved with 0.01 mM IPTG induction at 30°C incubation for 3 hours. We also found that the enzyme is more concentrated in the pellet cells as inclusion bodies. Furthermore, the in-silico analysis revealed that this enzyme consists of 233 amino acid residues. This enzyme’s predicted tertiary structure shows six β-sheets flanked by α-helixes and thus belongs to Group II haloacid dehalogenase. Based on the structural prediction, amino acid residues of Asp7, Ser121, and Asn122 are present in the active site and might play essential roles in catalysis. The presented study laid the foundation for recombinant haloacid dehalogenase production from P. aeruginosa local strains. It provided an insight into the utilization of recombinant local strains to remediate environmental problems caused by organohalogens.

An Insight of Co-Encapsulation Nigella sativa and Cosmos caudatus Kunth Extracts as Anti-Inflammatory Agent Through In Silico Study

This study analyzes anti-inflammatory activity from extracts of Nigella sativa and Cosmos caudatus Kunth co-encapsulated through in silico molecular docking. The LC-MS results revealed that extracts of N. sativa mostly contained thymoquinone and alpha-hederin, whereas quercetin and kaempferol were the major compounds in C. caudatus K. Nevertheless, the bioactive compounds are usually susceptible to degradation by exposure to light, heat, oxygen, which may limit its biological activity. Therefore, encapsulation is one of the promising techniques to protect bioactive compounds. Ligands were encapsulated with chitosan and sodium tripolyphosphate as wall materials. Cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) as the target enzymes were docked with a combination of these active compounds (non-encapsulated and encapsulated), using the HEX 8.0 program, and visualized using the Discovery studio visualizer software v16.1.0.15350. Interestingly, docking results of the combination of encapsulated ligands showed no interactions to COX-1 but interacted with COX-2. Therefore, co-encapsulation of extracts combinations has been suggested to act as anti-inflammatory agents targeted specifically to the COX-2 enzyme. The total energy of the encapsulated of combination of extract compounds to COX-2 were -1425.88 (mol/cal) for thymoquinone + quercetin; -1435.87 (mol/cal) for thymoquinone + kaempferol; 1175.97 (mol/cal) for quercetin + alpha hederin; -957.74 (mol/cal) for kaempferol + alpha hederin; and -283.3 (mol/cal) for diclofenac sodium, as a control NSAID drug. These suggest that encapsulated active compounds in N. sativa and C. caudatus K. have potency as a drug candidate for the selective NSAIDs category, which can be subjected to further in vitro and in vivo studies.

Simultaneous Effect of Ultrasonic and Chemical Treatment on the Extraction of Nanocellulose From Sugarcane Bagasse

The focus of this study was the simultaneous effect of ultrasonic and chemical treatment on the extraction of nanocellulose from sugarcane bagasse. Ultrasonic waves can accelerate the dispersion process of nanocellulose particles so that extraction runs faster and is environmentally friendly. The bagasse was treated by chemical treatment with ultrasonic waves, and then the nanocellulose was prepared using acid hydrolysis with ultrasonic waves. The effect of ultrasonication was investigated. The crystallinity of sugarcane bagasse, cellulose, and nanocellulose was analyzed by X-ray diffraction. Based on the diffractogram, there was an increase in the crystallinity of nanocellulose. The chemical composition of extracted cellulose and nanocellulose was analyzed by Fourier-transformed infrared spectroscopy. The results of the analysis showed that lignin and hemicellulose were removed from the bagasse during the extraction process. The analysis results also showed that the breaking of intramolecular hydrogen and glycosidic bonds occurred during the hydrolysis process. The morphology of bagasse, cellulose, and nanocellulose was analyzed by Scanning electron microscopy. While the particle size of nanocellulose was analyzed by the Particle Size Analysis instrument. The average size of nanocellulose particles was 132.67 nm.

Bandgap Energy of TiO₂/M-Chlorophyll Material (M=Cu²⁺, Fe³⁺)

The bandgap energy (Egap) of TiO2 material modified with metal-chlorophyll complex compounds (M = Cu2+, Fe3+) was observed. Chlorophyll (Chl) was isolated from cassava leaves, and its UV-Vis spectra showed absorption peaks in the Soret band region (410 nm) and in the Q band region (665 nm), which is the typical peak of chlorophyll. Copper(II)-chlorophyll complex was prepared from the reaction between chlorophyll and CuSO4.5H2O, while the iron(III)-chlorophyll was synthesized from chlorophyll and FeCl3.6H2O in methanol solvent under reflux at 65°C. The presence of copperand iron metals in the chlorophyll metal complexes was identified using Atomic Absorption Spectroscopy in methanol solution. The absorption of copper measured in Cu2+-Chl was 0.0488 (0.4805 mg/L), while the iron atom in Fe3+-Chl was 0.0050 (0.0195 mg/L). The UV-vis spectra demonstrate the hypsochromic shift of the Soret band to 405 nm (Cu2+-Chl) and 402 nm (Fe3+-Chl). The Infrared spectra of chlorophyll after being complexed with copper(II) shows the increase of vibrational absorption wavenumber of the C=N group from 1225.06 cm-1 to 1241.94 cm-1 indicates the coordination of the metal ion on the N atom in the pyrrole ring. The shift in the absorption band on the Fe3+-Chl spectrum was seen for the C=O ester group from 1720.49 cm-1 to 1721.10 cm-1 indicating the metal ion bonding in the C=O group of esters. The DR-UVis analysis of TiO2/metal-chlorophyll shows a bathochromic shift towards the visible light region. By using the Tauc plot method, it was observed that the Egap of TiO2 reduces from 3.08 eV to 2.89 eV and 2.93 eV in the compound of TiO2/Cu2+-Chl and TiO2/Fe3+-Chl, respectively.

Mass Effect of Coconut Shell-derived Activated Carbon on Adsorption of Benzene, Toluene, Ethylbenzene, and Xylene in Motorcycle Emissions

The use of motorized transportation in Indonesia is now proliferating. The higher the use of motorized vehicle-based transportation in an area, the higher the potential for air pollution. One of the air pollutants is a mixture of benzene, toluene, ethylbenzene, and xylene (BTEX). This study examines the effect of coconut shell-derived activated carbon adsorbent mass which is adjusted with different thicknesses on its adsorption ability for BTEX. The adsorbent is used to adsorb the emissions of the 1990 GL-Pro motorcycle with premium fuel. The results of gas chromatography-mass spectroscopy (GC-MS) show that motor vehicle emissions contain BTEX and other hydrocarbons. ANOVA variant analysis showed that the difference in mass of activated carbon in the range of this study did not provide a significant difference in BTEX adsorption.Keywords: adsorbent; motor vehicle emissions; BTEX pollutants; coconut shell

Stigmasterol and Stigmasterone from Methanol Extract of Calophyllum soulattri Burm. F. Stem Bark

Stigmasterol and Stigmasterone from Methanol Extract of Calophyllum soulattri Burm. F. Stem Bark. Calophyllum soulattri Burm. F. has been widely used for herbal medicine. Phytochemical investigation of C. soulattri contains a secondary metabolite of the steroid class. Steroid compounds have various biological activities, such as anti-inflammatory, antioxidant, antiproliferative, antibacterial, antimalarial, and anticancer. Two secondary metabolites steroids have been isolated and identified from the stem bark extract of C. soulattri. Isolation was carried out through the extraction (maceration), fractionation, and purification stages. Maceration is carried out using methanol as a solvent. Fractionation was carried out by vacuum liquid chromatography (VLC), and purification was by flash column chromatography. Identification of combined fractions and determination of pure isolates were used through thin-layer chromatography (TLC). The solvent used in the chromatography methods was a mixture of n-hexane and ethyl acetate. The structure isolates were identified by FTIR, 1H NMR, and 13C NMR and compared with literature data. Secondary metabolites steroids that have been isolated are identical compounds to stigmasterol and stigmasterone.

Docking and Molecular Dynamic Simulations Study to Search Curcumin Analogue Compounds as Potential Inhibitor Against SARS-CoV-2: A Computational Approach

Coronavirus is a pandemic in the world. It requires researchers and scientists to work hard to find a vaccine or drug to inhibit the development of the coronavirus. Many drugs have been used, such as remdesivir, lopinavir, and chloroquine. However, how effective is the use of these drugs for inhibiting the coronavirus’s growth? There is no research has been done. Curcumin is now known as one of the compounds that have some biological activities, and it is also can potentially be used as a CoV-2 inhibitor. The computational study, i.e., molecular docking and molecular dynamic, can help researchers to predict which compounds have the potential as an inhibitor against the CoV-2 coronavirus. In this study, lopinavir was used as a positive control. Lopinavir and 45 curcumin analog compounds were docked against the main protease protein with 6LU7 PDB ID. Based on the docking results, it was discovered that compound 1, compound 2, and compound 4 have the same binding orientation as lopinavir. Molecular dynamic simulation with the lowest binding free energy conformation was used to check these compounds’ stability. Only compound 4 was maintained to observe hydrogen bonding with Lys5 and Lys137 with a distance of 2.9 Å. The distance of hydrogen bonds and binding free energy over simulation time is essential to elucidate the potential compound’s affinity. For then, compound 4 can be used as a potential inhibitor against the CoV-2 coronavirus.

Performance of HDTMA-Br-Modified Indonesian Zeolite as a Drug Carrier Candidate for Diclofenac Sodium

Diclofenac sodium is a non-steroidal anti-inflammatory drug with a relatively short release time. This short release time promotes a more frequent drug consumption and could lead to side effects in the stomach, e.g., gastrointestinal disorders, gastrointestinal bleeding, and gastric ulcers. A drug delivery system with a slow-release activity is one of the promising technologies to control the drug amount released to the stomach. A surfactant-modified natural zeolite as a carrier for diclofenac sodium has been used in this study. This study focused on the preparation, characterization, and slow-release performance of HDTMA-modified natural zeolite as a carrier for diclofenac sodium. The zeolite underwent chemical and physical activation, as well as milling prior to use. It was proven that the zeolite used was dominated by mordenite and clinoptilolite with high stability properties towards acid treatments, as indicated by the XRD patterns. A modification of the zeolite surface using HDTMABr was also successfully performed, indicated by the appearance of peaks at wavenumbers of 2923.05 cm-1 and 2853.39 cm-1 (symmetrical and asymmetrical CH2 strains of HDTMA molecules, respectively) in the FTIR spectra. The synthesized HDTMA-modified natural zeolite also showed an excellent surface property such as surface area, pore-volume, and size, as indicated by the BET-BJH isotherms on the nitrogen adsorption. The slow-release performance of the zeolite-based drug delivery system was studied by investigating the adsorption-desorption behavior of HDTMA-modified zeolite towards diclofenac sodium. The HDTMA-modified zeolite adsorbed the diclofenac sodium of 54.01% at a pH of 7.5, the contact time of 60 min, and the initial concentration of 100 ppm. The adsorbed diclofenac sodium of 73.95% could be released from the HDTMA-modified adsorbent for 8 h, mimicking the time length of drug metabolism in the human body.