Jurnal Kimia Valensi
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Two Sesquiterpenes from n-Hexane Fraction of Curcuma soloensis Rhizomes and Their Antimicrobial Activities
Full text linkCurcuma soloensis is one of the medicinal plants that has the potential to be a source of bioactive compounds. The antimicrobial study of the bioactive compounds from C. soloensis was still limited. This study aimed to isolate the bioactive compounds from C. soloensis rhizomes and to evaluate their potential as antimicrobial agents. C. soloensis rhizome extraction was done using the maceration method with acetone and then fractionated with n-hexane: methanol (1:1). The compounds were separated and purified using vacuum liquid chromatography and radial chromatography. The structure of the isolated compounds was determined using the nuclear magnetic resonance (1H and 13C NMR) spectroscopy analysis and comparison with literature data. Antimicrobial activity assays of the extract, n-hexane fraction, and isolated compounds were carried out by microdilution methods against Escherichia coli, Staphylococcus aureus, Candida albicans, and Malaszezia furfur. Two bioactive compounds from the n-hexane extract of C. soloensis rhizome have been isolated: ar-curcumene and ar-turmerone. Antimicrobial test results on acetone extract, n-hexane fraction, and isolated compounds showed that ar-turmerone had the highest activity against S. aureus with a MIC value of 15.6 μg / mL. In comparison, ar-curcumene showed the same activity against all test microbes with a MIC value of 62.5 μg / mL. This study showed that secondary metabolite compounds of C. soloensis rhizomes have the potential to be developed as antimicrobial agents
Amino Acids Isolation from α-keratin of Javanese Goat (Capra hircus) Hair and Garut Sheep (Ovis aries) Hair Waste Using Acid Hydrolysis Method as BCAA Supplement
Full text linkJavanese goat and Garut sheep hair contain α-keratin, a protein that can be broken by hydrolysis to produce simpler amino acids. Feather waste generates millions of tons of α-keratin biomass originating from animal slaughterhouses, thereby raising health concerns. The utilization of acid hydrolysis is considered to be more cost-effective compared to enzymatic hydrolysis, and it provides a broader range of amino acid cleavage sites compared to enzymes, which exhibit specific cleavage. This study aimed to isolate amino acids from Javanese goat and Garut sheep hair through acid hydrolysis. The methods included hair sample preparation, acid hydrolysis used 6 M HCL at 110°C, reflux isolation, amino acid separation based on isoelectric pH 4.9 –5.4, functional groups analysis using FTIR, and analysis of amino acid content by HPLC methods. The results showed that the yield produced after isolation on Javanese goat hair samples was 0.92% and Garut sheep hair 0.32%, respectively. The FTIR spectrum showed amino acid functional groups in both samples, including carboxyl (COOH), amine (C-N primer), (C-S disulfide), and amide I (-CONH2). Successful breakdown of α-keratin proteins into simpler amino acids was achieved for Javanese goat and Garut sheep hair. Amino acid analysis of Javanese goat hair isolates revealed the presence of aspartic acid, threonine, serine, glutamate, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, histidine, lysine, and arginine amino acids, respectively. The highest content was isoleucine at 0.60% w/w. In conclusion, the isolated amino acids from Javanese goat hair can be used as a halal supplement that serves as nutrition in the body
Modified Natural Rubber Based on the Sulphur Curing System as Rubber Compound Formulation on Basic Design of Seismic Bearing
Full text linkIndonesia is highly susceptible to earthquakes, with the southern and western coasts of Java and Sumatra being the most vulnerable regions. Due to this vulnerability, it is necessary to establish a culture of disaster mitigation in the most fertile and heavily populated islands to reduce the number of fatalities and economic losses caused by earthquakes. One of the promising real-world seismic base isolation methods is using a rubber seismic bearing constructed of rubber and metal layers. This study aimed to examine the typical behavior of natural rubber compounds subjected to various sulfur-curing processes as basic designs in the manufacture of rubber seismic bearings. The experiment was carried out by arranging the sulfur curing system into three categories, namely an efficient which applied N-cyclohexyl-2-benzothiazole sulfonamide (CBS)/Sulfur (S) ratio as 1.4/0.15 and 1.4/0.25, semi-efficient with CBS/S ratio of 1.4/1.4 and 1.4/1.7, and conventional with CBS/S ratio of 1.4/3.0 and 1.4/3.5. The results showed that the ideal modification condition for NR macromolecule chain found in seismic-bearing rubber compound was a semi-efficient sulfur curing system with a CBS/S ratio of 1.4/1.4. It suggested that a semi-efficient sulfur curing system was appropriate for developing rubber compound formulation for seismic rubber bearings, mainly for low-damping types
Radiolabeling and In-Silico Study of 131I-(4-fluorobenzoyl-3-methylthiourea) as Radiopharmaceuticals for Breast Cancer Theranostics
Full text linkThe chemicals produced from thiourea are actively being studied as anticancer possibilities. In complexes with radionuclides like Iodine-131, the 1-(4-Fluorobenzoyl)-3-methyl thiourea is a promising ligand for theragnostic applications. This study aimed to label 1-(4-fluorobenzoyl-3-methylthiourea) with iodine-131 and observe its interaction with breast cancer receptors. The radiolabeling of 131I-(4-fluorobenzoyl-3-methylthiourea) uses the radioiodination method with Chloramine-T, and an in-silico investigation of breast cancer receptors was conducted. According to the results of molecular docking using AutoDockTools, this radiopharmaceutical molecule has the best activity on the HER2 receptor (PDB ID: 3PP0) compared to the native ligand and control positive, with a binding affinity of -6.13 kcal/mol and a Ki value of 32.05 mM. According to the molecular dynamics data using Desmond, the radiopharmaceutical molecule 131I-(4-Fluorobenzoyl-3-methylthiourea) displays good stability starting from the 50ns range. The indirect radioiodination method has successfully labeled 1-(4-Fluorobenzoyl-3-methylthiourea) with iodine-131
Modification of Coal Fly Ash Waste into Manganese-Oxide-Coated-Zeolite (MOCZ) to Adsorb Heavy Metal Ions Ni2+
Full text linkHigh consumption of coal as a source of electrical energy in Indonesia has resulted in piles of waste from coal burning, namely fly ash, which can damage the environment and harm health. Fly ash contains main oxides, namely silica (SiO2) and alumina (Al2O3), whose components are similar to zeolite, so they can be synthesized into zeolite-like material (ZLM) which can be used as an adsorbent for heavy metal Ni2+. Therefore, this research discussed the characterization of manganese-oxide-coated-zeolite (MOCZ) from fly ash waste as a heavy metal adsorbent. The research procedure consisted of preparation, purification, and activation stage of fly ash to obtain fly ash that is free from impurities, the stage of making sodium silicate and sodium aluminate, and zeolite synthesis. The resulting zeolite was then coated with manganese oxide to expand the surface area of the zeolite and increase the ability of zeolite to adsorb heavy metal Ni2+. The research results showed that fly ash waste that was coated with manganese oxide can adsorb heavy metal Ni2+. The adsorption of the Ni2+ metal ion solution by zeolite with MOCZ modification is in line with the pseudo-second-order kinetic and Langmuir isotherm
Synthesis and Characterization of Magnetic Molecularly Imprinted Polymers Targeting Capsaicin
Full text linkA novel magnetic molecularly imprinted polymers (MMIPs) was developed for the adsorption of capsaicin, a key component of capsaicinoids widely used in food additives and topical pharmaceuticals. Excessive use of capsaicin can lead to respiratory, skin, and oral disorders, necessitating effective monitoring methods. This study aimed to synthesize MMIPs and magnetic molecularly non imprinted polymers (MNIPs) using 4-vinyl pyridine as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the crosslinker, combined with an initiator in a 1:4:20 molar ratio. Magnetite nanoparticles (Fe3O4) were incorporated to facilitate magnetic separation. Characterization via particle size analyzer (PSA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) confirmed the successful synthesis of Fe3O4 nanoparticles, MNIPs, and MMIPs. PSA analysis for Fe3O4 nanoparticles showed an average size of 140.2 nm with a polydispersity index (PI) of 0.313, MMIPs showed an average particle size of 746.6 nm and a PI value of 0.397. FTIR spectra revealed characteristic absorption bands at 3429 cm−1 (O-H), 2958 cm−1 (C-H), 1732 cm−1 (C=O), 1155 cm−1 (C-O), and 580 cm−1(Fe-O), indicating successful Fe3O4 modification. SEM-EDS analysis showed non-spherical morphology due to bulk polymerization. TEM image results showed Fe₃O₄ nanoparticles were successfully coated with a molecularly imprinted polymer (MIP). The developed MMIPs effectively have a robust synthesis method and thorough analysis, laying the groundwork for future applications
Garciniaxanthone E and 12b-Hydroxy-des-D-garcigerrin A from The Tree Bark Garcinia dulcis and their Inhibitory Properties against Receptor Tyrosine Kinases
Full text linkTwo xanthone derivatives, garciniaxanthone E (1) and 12b-Hydroxy-des-D-garcigerrin A (2) have been isolated from ethyl acetate extract of the tree bark of Garcinia dulcis. The Ultraviolet (UV), Infrared (IR), Nuclear Magnetic Resonance (NMR), and Mass Spectrometry (MS) data analysis elucidated the structure of the isolated compounds. This study represents the first evaluation of compounds 1 and 2 in terms of their efficacy against receptor tyrosine kinases. The results showed that compound 1 exhibited weak activity with 12% inhibition against Insulin Receptor (InsR), while compound 2 showed moderate activity with 29% inhibition against epidermal growth factor receptor (EGFR). A molecular docking study targeting EGFR-TK suggests that the hydroxyl group at C-4 on compound 2 can be demolished to raise the inhibitory activity in future research
Nonenzymatic Sensor Based on Glassy Carbon Electrode Modified by Platinum Nanoparticles Decorated Reduced Graphene Oxide for Glucose Detection in Human Urine
Full text linkThis research aims to develop a sensitive and selective nonenzymatic electrochemical sensor for glucose detection using a glassy carbon electrode modified with platinum nanoparticles (PtNPs) decorated on reduced graphene oxide (RGO). The structural properties and surface morphology of PtNPs/RGO composite were characterized using Raman spectroscopy and scanning electron microscopy (SEM). In addition, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were employed to investigate glucose measurements in human urine samples. The developed sensor shows an increasing anodic peak of glucose with a linear response at a concentration range from 10 to 1000 µM, with a detection limit of 5 µM. The proposed sensor also demonstrated good reproducibility, indicated by the value of relative standard deviation (%RSD) of 3.9%, and maintained its current response over seven consecutive measurements. Moreover, the proposed sensor exhibited high selectivity for glucose detection against several potential interferences, such as potassium (K+), chloride (Cl−), magnesium (Mg2+), ascorbic acid, dopamine, and urea, with recovery values of 96-102%, which are acceptable within the analytical range. Furthermore, this proposed sensor successfully detected glucose in human urine samples, and their concentrations were not significantly different when measured with a commercial glucose sensor
Green Synthesis of Zinc Oxide Particles using Banana Peels and Tea Leaves Extracts for Rhodamine B Photodegradation
Full text linkRhodamine B is a widely used dye in the textile sector. However, the wastewater produced during the dyeing process presents a notable source of pollution, contaminating water and posing a threat to aquatic ecosystems due to its presence in liquid waste. Photocatalysis is a technique for breaking down toxic textile dye waste a semiconductor as a catalyst, valued for its high sensitivity and eco-friendly nature. In this research, zinc oxide particles were synthesized via a green synthesis approach using precipitation, employing natural capping agents from banana peel and tea leaf to degrade the synthetic dye of rhodamine B. The catalyst material was characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and ultraviolet-visible diffuse reflectance (UV-DRS). The photodegradation performance of rhodamine B was determined under UV light exposure for 3 hours. The XRD spectra of ZnO show the specific peaks of 2θ at 31.8°, 34.5°, and 36.3° with a crystallinity value of around 79.50%. The SEM result shows that the morphology of ZnO is in cotton-like form with a minimum band gap of 3.17 eV. The cotton-like ZnO particles demonstrated superior photodegradation efficiency for Rhodamine B, achieving 61.8%, compared to 47.9% with pure ZnO. It suggests that synthesizing ZnO particles with banana peels and tea leaf extracts boosts photodegradation efficiency by up to 20% compared to pure ZnO. This research highlights the potential of utilizing eco-friendly and sustainable methods as a greener approach for reducing waste in environmental applications
Dealumination Effect on ZSM-5 as a Bimetal Fe-Co Support for The Oxidative Desulfurization Process Catalyst
Full text linkPetroleum fuel is still the main energy source today but causes environmental problems such as SOx gas emissions. The Oxidative Desulfurization (ODS) method removes sulfur from fuel under mild conditions. ZSM-5 is a catalyst framework considered promising in the ODS process but the small pores cause a steric barrier. The hydrophobic, mesoporous Fe-Co/ZSM-5Hierarchy catalyst was designed using the dealumination method with steam treatment to overcome the steric barrier and biphasic hindrances which are problems in this ODS process. The Fe-Co/ZSM-5Hierarchy catalyst is effective for the ODS process at a temperature of 45 °C, 45 min, the amount of catalyst used is 0.2 g, oxidant at an O/S ratio of 2, and without mass transfer agents. The embedded Fe-Co ratio shows effective mass activity by providing a TOF number of 205 h-1 on the Fe-Co(5)/ZSM-5 Hierarchy and 157 h-1 on the Fe-Co(15)/ZSM-5 Hierarchy catalyst