Chimica et Natura Acta
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Study and Characterization of Nitration of Isovanillic Acid Derivatives using NMR and Mass Spectroscopy
No full textIsovanillic acid and its derivatives serve as precursors in the synthesis of EGFR tyrosine kinase inhibitors, which are used to treat cancer cell lines. A crucial step in this process is the nitration of isovanillic acid through nucleophilic aromatic substitution, resulting in 6-nitroisovanilic acid and its derivatives, which act as intermediates for forming a quinazolinone ring. However, this study revealed that direct nitration of isovanillic acid derivatives led to unexpected products, such as 3-hydroxy-4-methoxy-2,6-dinitrobenzoic acid (1) and 4-(3-(2-methoxy-4-nitrophenoxy)propyl)morpholine (4). Additionally, the optimal conditions for etherification of 2 with N-(3-chloropropyl)morpholine to produce 3 involved using Cs2CO3 in DMF and refluxing for 7 hours, achieving an 89% yield. All synthesized compounds were characterized using NMR spectroscopy, and mass spectrometry was employed for two compounds (3, 4). Compound 1 represents the first report of direct nitration of isovanillic acid. Compound 4 was synthesized for the first time from 3 through a one-pot process involving hydrolysis and decarboxylation, followed by nitration at carbon C-1 without metal catalysis, as confirmed by a NOESY 1D experiment. Moreover, the application of 4 could hold promise for future advancements in medicinal chemistry
Coating of Ti-6Al-4V Metal Alloys Nanotube with Hydroxyapatite-Gelatin-Polyvinyl Alcohol Composites using the Dip-Coating Methods
Full text linkThe Ti-6Al-4V metal alloy is an implantable material because of its strength, lightweightness, and corrosion resistance properties. Metal alloy surfaces need to be modified to improve corrosion resistance. Therefore, the study aims to modify the surface of Ti-6Al-4V metal alloys to form nanotube structures and to coat the hydroxyapatite composite (HAp)-gelatin-PVA in Ti-6Al-4V metal alloys. Nanotubes were formed by anodizing methods in an ethylene glycol-H2O (9:1) solution containing 0.6% NH4F at 20V for 3 hours. The result of SEM showed that the diameter of the nanotube hole is about 30−40 nm and that it is formed homogeneously. The result of coating nanotube metal alloys with composite HAp-gelatin-PVA is that they are evenly distributed and thicker. The morphology of a homogeneous small granule composite coating composite. The X-ray diffraction showed shows that the composite HAp-gelatin-PVA crystalline size coated on nanotube metal alloy is smaller than that of non-nanotube. Nanotube Ti-6Al-4V coated metal alloy with HAp-gelatin-PVA composites had shows poor bioactivity that had not beenand thus not able to increase the corrosion resistance of Ti-6Al-4V metal alloys
Isolation and Characterization of Cellulase Enzyme from Sago Bettle Larvae
Full text linkSago beetle larvae are larvae that consume cellulose and convert it into simple compounds with the help of cellulase enzymes. The enzyme is produced by bacteria found in the larvae's intestines. This study aims to characterize the cellulase enzyme from R8W bacteria, which is a cellulolytic bacterium and derived from sago beetle larvae. The characterization in this research included determination of the optimum temperature, the optimum pH, and the optimum substrate concentration of the enzyme. The methods in this study consisted of the production of enzymes; characterization of cellulase enzyme by DNS method; and measurement of cellulase enzyme activity on natural substrates. The results showed that the cellulase enzyme R8W bacterial isolates from beetle larvae were in optimum conditions respectively at a temperature of 50 °C (enzyme activity of 0.070 U/mL), pH 8 (enzyme activity of 0.069 U/mL), substrate concentration of 2% (enzyme activity of 0.063 U/mL); cellulase enzyme activity of R8W bacterial isolates from sago beetle larvae on rice husk cellulose as a natural substrate was 0.103 U/mL. The characteristics of the cellulase enzyme of R8W bacterial isolate from sago beetle larvae had an optimum temperature of 50 °C, an optimum pH of 8, and an optimum substrate concentration of 2%
Synthesis of 1,2-Di(phenyl)ethan-1,2-dione through Oxidation of 2-Hydroxy-1,2-Dipheniletanone by using Copper(II) Citrate
No full text1,2-Di(phenyl)-1,2-dione widely used in chemical and pharmaceutical industries and found as a framework in secondary metabolites can be obtained through oxidation of 2-hydroxy-1,2-diphenylethanone using strong acids, homogeneous, heterogeneous, and metal catalysts. However, these oxidation methods exhibit various drawbacks. This study reported the oxidation of 2-hydroxy-1,2-diphenylethanone by using copper(II) citrate to produce 1,2-di(phenyl)-1,2-dione. The oxidation performed with copper(II) citrate and ammonium nitrate in glacial acetic acid as solvent yielded 1,2-di(phenyl)-1,2-dione in 88% yield higher than the nitric acid method (79% yield). The FTIR, NMR spectriscopies, and mass analysis confirmed the structure of 1,2-di(phenyl)ethane-1,2-dione. The oxidation of 2-hydroxy-1,2-diphenylethanone using copper(II) citrate is proposed by the formation of Cu⁺ ions and a resonance-stabilized 2-hydroxy-1,2-diphenylethanone radical resulting in 1,2-di(phenyl)ethane-1,2-dione
The Activity of Unripe Wood Apple (Limonia acidissima Groff) Peel and Flesh Extracts in Inhibiting Diarrhe-Causing Bacteria
No full textDiarrhea is characterized by having liquid stool more often than usual, typically occurring three or more times within a 24-hour period. While rarely fatal, it can disrupt daily life and is often treated with antibiotics due to pathogens like Bacillus cereus, Shigella flexneri, and Salmonella typhimurium. An overgrowth of Escherichia coli can also be a contributing factor. Recent studies suggest that unripe wood apples may have antibacterial properties. This study evaluates the antibacterial activity of extracts from the peel and flesh of the fruit against the bacteria, as mentioned earlier. Using disk diffusion, microdilution, and bioautography methods, it was found that the ethanol extract inhibited Bacillus cereus and Shigella sonnei, while the flesh extract affected Bacillus cereus and Escherichia coli. The bioautography test, however, showed no antibacterial activity from either extract, likely due to their low concentration. In conclusion, the peel and flesh extracts of unripe wood apples exhibit potential antibacterial activity against diarrhea-causing bacteria, particularly Bacillus cereus
The Effect of Different Synthesis Solvents and Dialysis Processes on the Optical Properties of Carbon Dots from Spent Coffee Grounds using the Solvotermal Method
No full textThe distinctive optical properties of carbon dot (CD) make CD is one of the most widely developed carbon nanomaterials today. CD can be synthesized from materials that high in carbon content, such as spent coffee grounds. The optical properties of synthesized CD are influenced by several factors, including the solvent used to synthesize it and the purification method. The purification process that can be done is dialysis. However, this technique is not always used in several researches to purify CD. This study aims to synthesize CD from spent coffee grounds through solvothermal methods with three different solvents, which are water, 50% ethanol (v/v), and absolute ethanol that purified by dialysis and without dialysis and to characterize the differences in its optical properties. The results showed that CD was successfully synthesized with these three solvents, but the optical properties were different. All three solvents produce CD that emits blue light, but differ in intensity. The addition of ethanol can double the luminescence intensity of CD and CD synthesized with 50% ethanol produce the highest luminescence intensity. In addition, CD purified without dialysis produce twice as high luminescence intensity as CD purified by dialysis
Bioactive Compounds of Insulin Leaves (Smallanthus sonchifolius) as DPP4 Enzyme Inhibitors in Insulin Signaling Mechanism for the Treatment of Type 2 Diabetes Mellitus: In Silico Study
Full text linkType 2 Diabetes Mellitus (DM) is characterized by a relative insulin deficiency caused by pancreatic cell dysfunction and insulin resistance. Herbal-based traditional medicine can be an alternative, one of which is insulin leaf (Smallanthus sonchifolius), which has antidiabetic effects and can lower blood sugar levels by inhibiting glycogenolysis and gluconeogenesis. DPP4 inhibitors are a class of antidiabetic drugs used in the treatment of type 2 DM. This study aims to analyze and predict the binding patterns of flavonoid derivatives from insulin leaf (Smallanthus sonchifolius) compounds to the DPP4 enzyme inhibitor, to determine the binding affinity of these compounds to the target protein as an antidiabetic agent. The study was conducted using an in silico method, utilizing the Research Collaboratory for Structural Bioinformatics (RCSB), Avogadro Software, AutoDockTools (version 1.5.6), and Biovia Discovery Studio 2021 for molecular docking and prediction of binding patterns and affinity for the DPP4 N7F protein. The results of this study showed that the binding energy value obtained from the natural ligand N7F was -11.0 kcal/mol. The binding energy value for 1,19-dihydroxy-2,6,10,14-phytateraen-18-oic-acid with the N7F protein was -9.8 kcal/mol. Therefore, 1,19-dihydroxy-2,6,10,14-phytateraen-18-oic-acid has a more stable binding with the DPP4 enzyme N7F target protein. Based on the results obtained from molecular docking of the flavonoid derivative compounds from insulin leaf (S. sonchifolius), the compound 1,19-dihydroxy-2,6,10,14-phytateraen-18-oic-acid showed the most potential as a DPP4 enzyme inhibitor among the other compounds
In Silico Approach of Flavonol in Hibiscus sabdariffa as Proteasome Inhibitors Targeting the Ubiquitin-Proteasome Pathway
No full textMultiple myeloma is a blood cancer characterized by the abnormal proliferation of B cells that accumulate in the bone marrow. The proliferation of these cells depends on the role of the proteasome through the ubiquitin-proteasome pathway to degrade proteins that regulate the cell cycle, apoptosis, and stress response. The proteasome is the main target of proteasome inhibitors for the treatment of multiple myeloma. Flavonoid compounds in Hibiscus sabdariffa flowers, such as isoquercitrin, quercitrin, quercetagetin, isorhamnetin, and astragalin, have the potential to act as proteasome inhibitors. The insilico study aims to determine the potential of these compounds as proteasome inhibitors based on the results of molecular docking and molecular dynamics simulation. Molecular docking was performed using AutoDock Vina, PyMol, and BIOVIA Discovery Studio. The best compounds from the docking results were then tested for interaction stability through molecular dynamics using YASARA software. Quercetagetin, isoquercitrin, and isohamnetin, based on the results of molecular docking, have the lowest binding affinity of -6.0, -5.7, and -5.5 kcal/mol, respectively. The three compounds bind to the active site of the 20S proteasome, namely Thr1, Ala20, Thr21, and Ala49. The RMSD values in the molecular dynamics of quercetagetin (1.290 Å), isorhamnetin (1.839 Å), and carfilzomib (1.843 Å). The binding affinity of quercetagetin (-422.623 kJ/mol), isorhamnetin (-438.388 kJ/mol), and carfilzomib (664.956 kJ/mol). Molecular docking and molecular dynamics findings indicate that isorhamnetin binds to the amino acid residues Thr1 and Ala49, which are the active sites of the 20S proteasome
Synthesis of Hydroxyapatite-Zirconia Composite and Activity Test as Dental Implant Material
Full text linkHydroxyapatite (HAp) is one of the bioceramics that is widely used in various fields, one of which is the health sector as a dental implant material. One of the reasons is that hydroxyapatite has good biocompatibility. In this study, natural calcium sources such as eggshell waste were utilized for the synthesis of hydroxyapatite. However, its mechanical properties do not yet meet the requirements as a dental implant material, its modification is usually done by adding other compounds, such as zirconium oxide. Zirconium oxide can be used as a support material because it has good strength, toughness, and durability as a dental implant. Therefore, in this study, a hydroxyapatite-zirconium oxide (HAp-ZrO2) composite was synthesized for dental implant material. This study aims to determine the effect of adding ZrO2 on increasing the mechanical and corrosion resistance of HAp. The research methods include isolation of CaO from chicken eggshells, synthesis of hydroxyapatite, synthesis of HAp-ZrO2 composite, hardness test, and corrosion resistance test. Based on SEM images, the addition of ZrO2 can reduce the level of HAp agglomeration. The addition of ZrO2 to HAp did not significantly affect the increase in HAp hardness since the zirconia phase formed is possibly dominated by the cubic phase. The optimum HAp-ZrO2 composite was obtained with a variation of HAp-90%-ZrO2-10% which showed the highest crystallinity of 75.37% with a crystal size at 10.15 nm with corrosion resistance comparable to pure HAp.Hydroxyapatite (HAp) is one of the bioceramics that is widely used in various fields, one of which is the health sector as a dental implant material. One of the reasons is that hydroxyapatite has good biocompatibility. In this study, natural calcium sources such as eggshell waste were utilized for the synthesis of hydroxyapatite. However, its mechanical properties do not yet meet the requirements as a dental implant material, its modification is usually done by adding other compounds, such as zirconium oxide. Zirconium oxide can be used as a support material because it has good strength, toughness, and durability as a dental implant. Therefore, in this study, a hydroxyapatite-zirconium oxide (HAp-ZrO2) composite was synthesized for dental implant material. This study aims to determine the effect of adding ZrO2 on increasing the mechanical and corrosion resistance of HAp. The research methods include isolation of CaO from chicken eggshells, synthesis of hydroxyapatite, synthesis of HAp-ZrO2 composite, hardness test, and corrosion resistance test. Based on SEM images, the addition of ZrO2 can reduce the level of HAp agglomeration. The addition of ZrO2 to HAp did not significantly affect the increase in HAp hardness since the zirconia phase formed is possibly dominated by the cubic phase. The optimum HAp-ZrO2 composite was obtained with a variation of HAp-90%-ZrO2-10% which showed the highest crystallinity of 75.37% with a crystal size at 10.15 nm with corrosion resistance comparable to pure HAp
Potential of Chitosan-Encapsulated Mango Leaf Extract Nanoemulsion as Fruit Packaging
No full textFruits have a relatively short shelf life. One of the extensively researched preservation methods for fruits is edible coating. Edible coating is a method of coating food products with a polymer layer. Considering the environmental and sustainability aspects, edible coatings were synthesized from biodegradable polymers derived from polysaccharides. Chitosan is a widely developed and researched type of biopolymer due to its antimicrobial activity. In addition to antimicrobial activity, antioxidant properties are important in food packaging applications. Mango leaves (Mangifera indica L.) contain various secondary metabolites that play a role in antioxidant activity, such as mangiferin, gallic acid, flavonoids, and gallotanin. In this study, mango leaf extract nanoemulsion was synthesized to improve the antioxidant and anti-UV properties of biopolymer chitosan-based fruit packaging. Mango leaf extract nanoemulsion was synthesized using surfactant and ultrasonication methods. The results of Particle Size Analyzer (PSA) measurements showed that the size of all nanoemulsions was 83-99 nm. Observations with Transmission Electron Microscope (TEM) showed that the nanoemulsion was spherical with a 15-46 nm size range. The UV-Vis spectrophotometer instrument was used to test antioxidant properties using the DPPH reagent and anti-UV activity. These tests showed that adding mango leaf extract concentration to the nanoemulsion system increased DPPH inhibition and absorbance against UV light. The results of the performance test of mango leaf extract nanoemulsion encapsulated by chitosan have a high potential to be used as a bio-based edible coating matrix and a substitute for materials that are difficult to degrade