Jurnal Kimia Riset

VALIDATION OF HEADSPACE SOLID-PHASE MICROEXTRACTION WITH GAS CHROMATOGRAPHY-FLAME IONISATION DETECTOR METHOD FOR ALCOHOL ANALYSIS ON GASTRIC FLUID

Nazaratun Thaiyibah, Mochammad Yuwono, Ahmad Yudianto — Fri, 08 Dec 2023 00:00:00 +0700

Identifying the concentration of alcohol compounds in postmortem analysis of biological fluids can help the investigation, just as postmortem analysis of gastric juices can reveal the concentrations of alcohol consumed. However, an efficient and effective combination of extraction and measurement methods is required when looking at complex postmortem samples. Therefore, a headspace-solid phase microextraction (HS-SPME) method was developed using gas chromatography with a flame ionization detector (GC-FID) to identify postmortem alcohol concentrations. This present study optimizes and validates an effective and efficient method for postmortem alcohol extraction and quantification in gastric fluid. The optimal conditions for HS-SPME extraction using 65μm Polydimethy lsiloxane Divinyl benzene (PDMS/DVB) fiber for analyte isolation were 15 minutes. at 60°C and an exposure time of 1 minute. The validation investigation shows that the suggested approach satisfies the criteria for linearity, precision, accuracy, LOD, and LOQ for postmortem measurement of alcohol in gastric fluid.

DETERMINATION OF VITAMIN C CONTENT IN BELL PEPPER (Capsicum annuum L.) WITH DIFFERENT PROTIC POLAR SOLVENT BY UV-VIS SPECTROSCOPY

Fawait Afnani, Jamilah Hamidi Yanti, Wiwit Sri Werdi Pratiwi — Fri, 08 Dec 2023 00:00:00 +0700

Bell pepper can be an antioxidant and has many health benefits because of the high content of vitamin C. Vitamin C contents in yellow and orange bell peppers were extracted using different protic polar solvents and analyzed using the UV-Vis Spectrophotometry method. In this research, the bell peppers were extracted using the maceration technique for two days in 90% concentration of solvents (methanol and ethanol, respectively). Subsequently, the maximum wavelength was determined, and then 100 ppm ascorbic acid was used as a standard solution to analyze vitamin C content. Linearity based on a calibration curve is used to obtain the correlation coefficient of concentration between the standard solution and vitamin C levels in the sample. The result of UV-Vis spectroscopy analysis of this sample shows 373.5 nm of λ_max. The linearity is shown in the equation y = 0.0006 x + 0.019. The vitamin C content in all samples had significant differences based on randomized complete block design (RCBD) test result with α = 0.05. The vitamin C level in the yellow pepper sample with an ethanol solvent (340 mg/100 g) was higher than that of the orange pepper sample with ethanol (251 mg/100 g). Meanwhile, the vitamin C content in the sample of yellow peppers with methanol solvent (562.5 mg/100 g) was smaller than that of orange peppers with methanol solvent (757.5 mg/100 g). These contents indicated a different result in the level sources of vitamin C, even if the maceration process used a solvent with a higher dielectric constant.

DIFFERENT ROUTES FOR THE SYNTHESIS OF BENZALDEHYDE-BASED DIHYDROPYIMIDINONES VIA BIGINELLI REACTION

Yan Alamanda Ilfahmi, Arif Fadlan — Fri, 08 Dec 2023 00:00:00 +0700

Multicomponent reactions involving three or more reactants are commonly used to prepare dihydropyrimidinone with various bioactivities. This study reports the different routes for the synthesis of benzaldehyde-based dihydropyrimidinone via the Biginelli reaction and investigates the yield of the obtained products. The synthesis was performed via routes A, B, C, D, and E based on the formation of iminium, enamine, and Knoevenagel intermediates between urea, benzaldehyde, and ethyl acetoacetate. Route A, through a one-pot reaction via iminium, produced dihydropyrimidinone with a yield of 58%. The product from route B via iminium was obtained in 62% yield. Route C and D occurred via enamine at room temperature, and reflux gave the product 31% and 40% yield, respectively. Route E involving Knoevenagel intermediate provided the product in a 38% yield. ¹H NMR, FTIR, and MS spectroscopic techniques were used for structure elucidation.

WATER ROLE ON DIELS-ALDER REACTION OFPRENYLATED FLAVONOIDFORMATIONIN Boesenbergia pandurata: MECHANISM STUDY

Rahmanto Aryabraga Rusdipoetra, Kautsar Ul Haq — Fri, 08 Dec 2023 00:00:00 +0700

Panduratin A is a prenylated flavonoid derivative from Boesenbergia pandurata with many potential biological activities. The biogenesis of this compound and its derivatives is believed to involve a Diels-Alder reaction between monoterpenoid and chalcone derivatives. This study provides insight into modeling biogenesis through the Diels-Alderreaction for Panduratin A and derivatives biosynthesis. We are using M06-2X/6-31G(d)//PM6 level of theory to explore the potential energy surfaces, asynchronicity degree, and global electron density transfer. Explicit water was applied to mimic physiological conditions. Contrary to the fact that water accelerates this reaction through hydrogen bonding catalysis, we found that water could slow this reaction. These results suggest that this reaction proceeds very slowly under physiological conditions, and enzymes catalyze this reaction.

EFFECT OF MAGNETITE AND CHITOSAN-MAGNETITE ADDITION ON BACTERIAL LEVELS AND NH3-N (FREE-LIVING N2-FIXING BACTERIA CULTURE)

Ali Umar, Deden Saprudin, Fahrizal Hazra — Fri, 08 Dec 2023 00:00:00 +0700

Free-living N₂-fixing bacteria are essential in the soil because they provide a source of nitrogen in the form of ammonium needed by plants to be used in building protein blocks. The fixation of free N₂ needs to be increased by adding nanomaterials such as magnetite (Fe₃O₄), which has an active group and can be a source of nitrogenase enzyme cofactor. In this study, increased N₂ fixation used N₂-fixing bacteria in Burks medium. This increase was determined by measuring NH₃ levels using the Phenate method formed after Burks medium was treated with Fe₃O₄ and chitosan-magnetite (CS-Fe₃O₄). The study found that the number of bacteria can be well decreased. This research showed that using Fe₃O₄ and CS-Fe₃O₄ increased NH₃-N levels in cultures of free-living nitrogen-fixing bacteria by 15.40% and 75.54%. For future development, it can be in the form of optimization, the effect of adding the same material to plant secondary metabolites, and the mechanism of bacteria in using the material.

THE EFFECT OF SURFACTANT ON PRE-MORDANTING AND pH OF DYEING PROCESS WITH NATURAL DYES

Wulan Safrihatini Atikah, Ikhwanul Muslim, Sandi Mu’min Pratama — Fri, 08 Dec 2023 00:00:00 +0700

The dyeing process with natural dyes has disadvantages, including poor color fastness. A mordanting process is required to overcome these disadvantages. Conventional mordanting processes often use metal salts. This research will substitute the mordanting process using surfactants as mordant substances. The pH of the process influences the application of dyeing with natural dyes. This study aims to determine the effect of the pre-mordant process using surfactants and the pH of the dyeing process on the color characteristics of cotton and silk fabrics dyed with Cocos nucifera L dye extract. The surfactants used were cationic and non-ionic polymeric surfactants. This study was conducted in phases. The first phase involved the extraction of coconut fiber, and the second phase involved pre-mordanting the fiber with surfactants. The third stage is the dyeing process, which has variations in pH 3, 7, and 9. The evaluation results show that cationic surfactants have the potential to be used as a mordant and provide an increased anti-bacterial effect on processed fabrics. The optimal use of cationic surfactants was obtained using a concentration of 9 g/L and pH 7 for the cotton dyeing process. The optimum concentration was obtained at 9 g/L for the silk dyeing process, and the dyeing pH was 3.

CONVERSION OF PINEAPPLE PEEL GLUCOSE INTO BIOETHANOL USING SIMULTANEOUS SACCHARIFICATION AND FERMENTATION (SSF) METHOD AND SEPARATE HYDROLYSIS AND FERMENTATION (SHF) METHOD

Hasri Tri Maya Saragih, Jhony Hartanta Sembiring, Elfrida Ginting — Fri, 08 Dec 2023 00:00:00 +0700

This study aims to determine the bioethanol yield and characteristics from pineapple peel with two methods such as Simultaneous Saccharification and Fermentation (SSF) and Separate Hydrolysis and Fermentation (SHF). The percent yield of bioethanol produced from the fermentation of pineapple peel (Ananas comosus) with the Simultaneous Saccharification and Fermentation method was 63.50%, while the yield of bioethanol from the Separate Hydrolysis and Fermentation method was 58.75%. The physical characteristics of bioethanol pineapple peel waste using Simultaneous Saccharification and Fermentation method has a density of 0.8237 w/v whilst with Separate Hydrolysis and Fermentation is 0.8858 w/v. Furthermore, viscosity of bioethanol using Simultaneous Saccharification and Fermentation is 1.05 Cp whereas using Separate Hydrolysis and Fermentation is 1.02 Cp. Pineapple peel bioethanol method of Simultaneous Saccharification and Fermentation has concentration of 13% while Separate Hydrolysis and Fermentation method has concentration of 7.92%. FTIR spectra from SHF bioethanol missing the peak correlated with CH, CH₃, and CO. These missing peaks is due to the high percentage of water. Furthermore, bioethanol from SSF method showed peaks corresponding to CH, CH₃, and CO functional groups. It can be concluded that SSF method give bioethanol with optimum result.

DEGRADATION OF TETRACYCLINE BY FLOATING PHOTOCATALYST TiO2/Ni-COCONUT FIBER

Fri, 08 Dec 2023 00:00:00 +0700

The photocatalyst process involves light (photons) as an energy source and catalysts such as TiO₂ to accelerate the reaction. Efforts are made to reduce the band gap energy of TiO₂ by shifting the absorption towards visible light using metal cation doping, such as Ni^2+, and they can float on the surface with coconut fiber. XRD characteristics with TiO₂ diffractogram experienced a 2θ shift as an indication that Ni has entered the TiO₂ structure and seen some peaks decreased in intensity after being embedded with coconut fiber as an indication that TiO₂/Ni has successfully attached to the fiber. The band gap energy on TiO₂ is 3.21 eV with a wavelength of 386.5 nm in UV light. TiO₂/Ni-coconut fiber experienced a shift in band gap energy to 3.09 eV with a wavelength of 400.9 nm, which is in visible light. This indicates that Ni has successfully entered the TiO₂ structure. The TiO₂/Ni catalyst embraced with coconut fiber has a higher degradation activity than the catalyst without an embrainer, with a percent degradation of 28.66% for 120 minutes of irradiation. This is influenced by the amount of light that can be absorbed during the photocatalysis process.

QSAR ANALYSIS USING SEMI-EMPIRICAL AM1 METHOD, MOLECULAR DOCKING, AND ADMET STUDIES OF CHALCONE DERIVATIVES AS ANTIMALARIAL COMPOUNDS

Muhammad Akbar S Kurniawan, Muhamad Jalil Baari, Sariyanti, Finarisnawati — Fri, 08 Dec 2023 00:00:00 +0700

Malaria is a serious caused by protozoan parasites such as Plasmodium groups and has fatal consequences for human health. The increase in the resistance of the Plasmodium parasites toward existing antimalarial drugs prompts the exploration of novel compounds. In this study, quantitative structure-activity relationship (QSAR) analysis using the semi-empirical AM1 method was conducted to identify the optimal model that relates physicochemical properties and biological activity of chalcone derivatives. In addition, ADMET prediction and molecular docking were also carried out. Multilinear regression calculations for statistical parameters of QSAR models revealed that Model 4, with 11 independent variables, provided the best predictions and exhibited a robust correlation with antimalarial activity represented by inhibitory concentration (IC₅₀). ADMET predictions indicated favorable absorption, distribution, metabolism, excretion, and toxicity properties, particularly for B₂D, showing promising antimalarial attributes. Molecular docking studies targeting 5 mutated PfDHODH proteins revealed B₂D’s potential to reach therapeutic targets efficiently. It has low docking scores for mutations I (-10.5 kcal/mol), II (-8.6 kcal/mol), and V (-10.5 kcal/mol) with RMSD < 2Å, in carrying out its role for antimalarial activity. This research successfully identifies B₂D as an efficient inhibitor of PfDHODH receptors. Thus, it is a highly promising novel antimalarial drug.

STUDY MOLECULES DOCKING OF ALKALOIDS IN KRATOM ON SEROTONIN TRANSPORTER (SERT), NOREPINEPHRINE TRANSPORTER (NET), AND MONOAMINE OXIDASE (MAO)

Dandi Irawan, Bambang Wijianto, Harianto IH — Fri, 08 Dec 2023 00:00:00 +0700

Kratom (Mitragyna speciosa Korth) is a tropical plant originating from Southeast Asia that predominantly contains alkaloid compounds and can potentially maintain levels of monoamine compounds in the body to treat depression. The study aimed to examine the potential of 8 alkaloid compounds in kratom as antidepressants towards four target proteins: Serotonin Transporter (SERT), Dopamine Transporter (DOPAT), Leucine Transporter (LEUT), and Monoamine Oxidase (MAO) via molecular docking. The Pyrx program is used with exhaustiveness 106 as the protocol, and the grid is adapted to the active site of each receptor. The affinity values of the alkaloid compounds in kratom are mitragynine, 7-hydroxy mitragynine, speciociliatine, paynantheine, speciogynine, corynantheidine, mitraciliatine, and 9-hydroxycorynantheidine, for MAO were -7.1, -6.1, -5.7, -6.7, -5.7, -7.7, -5.7, and -5.7 kcal/ mole. All compounds bind to amino acid residues in the target protein through hydrogen and pi (π) bonds. All the tested alkaloid compounds have the potential to be re-uptake inhibitors SERT, DOPAT, LEUT, and Monoamine Oxidase (MAO).