Jurnal Kimia Valensi is a double blind peer-reviewed and open access journal published by Department of Chemistry, Faculty of Science and Technology Syarif Hidayatullah Jakarta State Islamic University. This journal focuses on chemical research, particularly research related to the use of Indonesia's natural resources in the development of nanomaterials, pharmaceutical and food industries. We welcome articles coming from Indonesia and overseas, capturing the rapid development of chemistry.
Department of Chemistry, Faculty of Science and Technology Syarif Hidayatullah Jakarta State Islamic University
Indonesian Black Tea (Camellia sinensis) as a Potential Acetylcholinesterase Inhibitor Against Alzheimer’s Disease: Docking, DFT, and In Vitro Evidence
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder predominantly affecting the elderly and characterized by dementia. AD pathology involves impaired cholinergic neurotransmission, largely due to β-amyloid (Aβ) plaque accumulation, which inhibits choline acetyltransferase (ChAT) and reduces acetylcholine (ACh) levels. Acetylcholinesterase (AChE) contributes to AD progression by hydrolyzing ACh and promoting Aβ plaque formation, making it a key therapeutic target. This study investigated natural compounds from black tea (Camellia sinensis) as potential AChE inhibitors. Molecular docking analyses assessed interactions between bioactive compounds from aqueous black tea extracts and AChE, followed by evaluation of bioavailability, biological activity, toxicity, stability, and reactivity. Epigallocatechin gallate exhibited the strongest binding affinity (∆Gbind = –12.2740 kcal/mol), forming extensive interactions with the catalytic active site located at the bottom of a deep and narrow gorge (~20 Å). Density Functional Theory (DFT) analysis confirmed its high stability and favorable reactivity in complex with AChE. In vitro validation using black tea extracts from Bogor, Indonesia, showed significant AChE inhibition with an IC50 value of 44.85 ± 1.48 µg/mL. These findings highlight the promising potential of Indonesian black tea as a natural alternative for Alzheimer’s disease therapy.
Jurnal Kimia VALENSI, Volume 11, No. 2, November 2025
Copyright (c) 2025 Mega Safithri, Rini Kurniasih, Dimas Andrianto, Ukhradiya Magharaniq Safira Purwanto, Muhammad Marsha Azzami Hasibuan, Rini Madyastuti Purwono, Maheswari Alfira Dwicesaria, John G. Acton https://creativecommons.org/licenses/by-sa/4.0
Eudesman-Type Sesquiterpenoids from Stem Bark Dysoxylum gaudichaudianum and Cytotoxic Evaluation Against Human HeLa Cervical Cancer
Two eudesmane-type sesquiterpenoids were isolated from the stem bark of Dysoxylum gaudichaudianum: 6α-hydroxy-eudesm-4(15)-en-1-one (1) and eudesm-4(15),7-dien-1β-ol (2). This study represents the first report of these compounds not only from D. gaudichaudianum but also from the genus Dysoxylum. The cytotoxic potential of two sesquiterpenoids was assessed against human cervical carcinoma (HeLa) cells employing the Resazurin-based PrestoBlue assay. Using cisplatin as a positive control, compound 1 exhibited moderate cytotoxicity with an IC₅₀ of 28.04 µM, whereas compound 2 showed comparatively weaker activity, with an IC₅₀ of 58.37 µM. Their structures were elucidated through comprehensive spectroscopic analyses, including HR-ESI-MS, ¹H NMR, and ¹³C NMR. Structure–activity relationship analysis indicates that hydroxylation at C-6 enhances cytotoxic activity, whereas the C-6/C-7 olefinic moiety reduces potency, likely due to increased molecular rigidity, highlighting key structural features for activity modulation in the eudesmane scaffold.
Copyright (c) 2025 Faizah Maira, Al Arofatus Naini, Tri Mayanti, Kindi Farabi, Sofa Fajriah, Rurini Retnowati, Unang Supratman https://creativecommons.org/licenses/by-sa/4.0
Unraveling the Influence of Type and Position Heteroatoms (N, O, S) on Asphaltene Aggregation Patterns
Asphaltenes, the heaviest fraction in petroleum and coal, are composed of polycyclic aromatic hydrocarbons (PAHs) with aliphatic side chains and heteroatoms (N, O, S). Previous studies have shown that these heteroatoms have a significant influence asphaltene aggregation. This study investigates the impact of heteroatom position and type, as well as solvent, on asphaltene aggregation behavior by employing molecular dynamics simulations of modified CA21 asphaltene. Simulations were conducted using GROMACS 2024.3. Analysis of simulation trajectories revealed that in water, all asphaltene models exhibited asphaltene-asphaltene radial distribution functions (RDFs) below 1 nm, indicating predominantly parallel or parallel-offset π-π interactions. In contrast, asphaltenes with an oxygen heteroatom at the end of the aliphatic chain when dissolved in hexane and toluene solvents, displayed unique shape aggregation, attributed to hydrogen bonding between the terminal oxygen atoms. The presence of heteroatoms within the aliphatic chain generally slowed aggregation, with the observed order of aggregation rates being S > N > O.
Copyright (c) 2025 Mia Ledyastuti, Intan Maulidhian Aribowo, Muhammad Fahri Afiki https://creativecommons.org/licenses/by-sa/4.0
In-Silico Studies of Potential Anti-Alzheimer Compounds from Spondias dulcis
Alzheimer's is a chronic neurodegenerative disease characterized by low levels of acetylcholine and the accumulation of abnormal neuritic plaques, leading to rapid memory decline and cognitive impairment. Compounds found in the kedondong plant (Spondias dulcis) have been reported to exhibit in vitro activity as acetylcholinesterase inhibitors. This study examines the potential of active compounds in Spondias dulcis in their interaction with acetylcholinesterase, an enzyme implicated in the pathogenesis of Alzheimer's disease. The enzyme was obtained from the Protein Data Bank (PDB ID: 4EY7). The test ligands were screened based on Lipinski's rule and docked with the receptor. The results of molecular docking which yielded the five best affinity energy values were followed by ADMET testing (absorption, distribution, metabolism, excretion, and toxicity). The test ligand ellagic acid deoxyhexoside showed binding energy at -11.213 kcal/mol. Molecular dynamics simulations were performed using YASARA with AMBER14 force fields for 50 ns. The test ligand ellagic acid eoxyhexoside showed an MM-PBSA value of -51.277 kcal/mol and exhibited good complex stability with an average total RMSD value of 2 Å and low inter-residue fluctuation values. These findings are consistent with the results obtained from the comparator ligand, donepezil. Therefore, compounds in Spondias dulcis have the potential to act as acetylcholinesterase inhibitors and can be considered for the development of therapies for Alzheimer's disease.
Copyright (c) 2025 Ahmad Fathoni https://creativecommons.org/licenses/by-sa/4.0
Hydrothermal Growth of Titanium Dioxide Thin Films on Conductive Substrates: Insights into Optical Properties
Titanium dioxide (TiO2) thin films were deposited on fluorine-doped tin oxide (F:SnO2/FTO) conducting glass using the hydrothermal method. The X-ray diffraction (XRD) patterns confirmed that the TiO2 thin films crystallize in the rutile phase, exhibiting high crystallinity. The Fourier Transform Infrared (FTIR) spectrum confirmed the interaction between the FTO substrate and the TiO2 layer, indicated by an absorption peak in the range of 400 cm-1 to 900 cm-1. These peaks correspond to Ti–O–Ti and Ti–O vibrations within the octahedral structure of TiO₆ and Sn–O–Ti vibrations, indicating the bonding between the FTO substrate and the TiO₂ surface. Scanning Electron Microscopy (SEM) images provide detailed visualization of the morphological features of the TiO₂ thin films deposited on FTO glass, as evidenced by the prolonged hydrothermal processing resulting in the formation of thicker films. In addition, the interface between the TiO₂ layer and the FTO substrate is well-defined and continuous. UV-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS) analysis showed enhanced light absorption with increasing film thickness, which was also visually noticeable. As a result, the band gap energy decreases with increasing thickness, indicating that less energy is required to excite electrons from the valence band to the conduction band.
Copyright (c) 2025 Yulia Eka Putri, Tio Putra Wendari, Retno Dyah Wulandari, Melvi Muharmi, Mai Efdi, Refinel Refinel https://creativecommons.org/licenses/by-sa/4.0
Experimental and Molecular Docking Study of 3′,4′,5′-Trimethoxychalcones Targeting Overexpressed Protein in HCT-116 Colon Cancer Cells
Cancer poses a substantial global health challenge. Colorectal cancer (CRC) is the second leading cause of cancer-related mortality after lung cancer and is associated with high mortality rates worldwide. Chalcones have attracted significant interest because of their diverse biological properties, including potential anticancer effects. In this study, five 3′,4′,5′-trimethoxychalcones (1-5) were tested against HCT-116 colon cancer cells using an MTT assay for the first time. Molecular docking was conducted to predict molecular interactions targeting three proteins (tubulin, EGFR, and CDK2). Among the five, four compounds (1, 3, 4, and 5) exhibited strong inhibitory activity against HCT-116 colon cells, with IC50 values < 10 µM. Compounds 1-5 showed potency as drug candidates based on the Lipinski rules and pharmacokinetic profiles using SwissADME and pkCSM online tools. Moreover, molecular docking was performed on compound 5 against three protein targets (tubulin, EGFR, CDK2) with binding affinities of -7.4, -7.3, and -8.5 kcal/mol, respectively, and showed major H-bond interactions. Therefore, these results suggest that compound 5 could be a potential inhibitor to be developed in future studies, both in vitro and in vivo, to understand its inhibition mechanism and efficacy.
Copyright (c) 2025 Ade Danova, Piyanuch Wonganan, Elvira Hermawati, Fera Kurniadewi, Iqbal Musthapa, Warinthorn Chavasiri https://creativecommons.org/licenses/by-sa/4.0
Synthesis and Characterization of Copoly(Anethole-Stearyl Acrylate) as Phenol Adsorbent
This study aims to synthesize copoly (Anethole-stearyl acrylate, SA) through cationic polymerization at room temperature (28–36°C) under a nitrogen atmosphere. The synthesis was carried out without a solvent using BF3O(C2H5)2 as the initiator. SA was added in varying weights of 2%, 4%, and 6% relative to anethole. The product obtained from the synthesis was then applied as a phenol adsorbent using the batch method at different contact times. FTIR (Fourier Transform Infrared) analysis showed that methoxy group (-OCH3) termination occurred at wavenumber 1147 cm-1, followed by the loss of vinyl group (C=C) at 1633–1654 cm-1. In addition, the loss of =C-H vinyl bending and stretching group absorption occurred at 964–998 cm-1 and 3025–3095 cm-1, respectively. Structural analysis using 1H-NMR showed the loss of the vinyl group proton signal at a chemical shift (δH) of 5.8–39 ppm. The addition of 2%, 4%, and 6% SA led to an increase in intrinsic viscosity of 26.891, 41.093, and 55.336, respectively. The morphology of copoly showed the presence of various cavities. The degradation temperature of the product increased with the addition of SA. During the application of copoly as a phenol adsorbent, the 6% (w/w) concentration had the largest adsorption capacity of 2.22 mg/g.
Copyright (c) 2025 Desi Suci Handayani, Edi Pramono, Anita Kusuma Dewi https://creativecommons.org/licenses/by-sa/4.0
Preparation and Characterization of Pt/TiO2 Nanotube Arrays (TNAs) Cathode by Photoreduction Method for Hydrogen Evolution
TiO2 nanotube arrays were fabricated using a two-step anodization method. TNAs have been modified by the photoreduction technique with Pt as the cathode in the photoelectrocatalytic zone for the reduction reaction of H+ to produce hydrogen. TNAs with Pt were modified using H2PtCl6 as the precursor by immersion of this solution on the TNA substrate. Pt/TNAs were characterized using SEM-EDX, UV-Vis DRS, XRD, Raman Spectroscopy, Photoluminescence (PL), and photoelectrochemical analysis. The results show that the morphology of TNAs in the tube forms 2.1mm in height, and Pt nanoparticles are formed on the mouth wall of the tube with a size of approximately 10nm. EDX analysis shows that the composition of Pt/TNAs is approximately 0.15%, Ti 37.09%, and O 62.76%, indicating that Pt has been decorated on the TNAs photoanode. The band gap of Pt/TNAs was 2.82 eV. The diffractogram shows three groups of diffraction peaks, indicating the presence of anatase TiO2, Ti as a substrate, and Pt, which has been modified in the TNAs. The Raman peaks of TNAs are confirmed to appear at Raman shifts of 144.75, 196.51, 395.94, 517.14, and 638.85 cm-1. PEC cathodes for hydrogen production using Pt-decorated TNAs have been successfully prepared using photoreduction.
Copyright (c) 2025 Sherly Kasuma Warda Ningsih, Rahmat Wibowo, Jarnuzi Gunlazuardi https://creativecommons.org/licenses/by-sa/4.0
In Silico Analysis of Tea Leaf Compounds Targeting Inflammatory Pathways and Acne-Related Genes
Acne (Acne vulgaris) is a chronic skin disease affected by Cutibacterium acnes infection and inflammatory pathways that trigger innate immune responses, such as inflammasome activation. The expression of inflammation-related genes plays a critical role in acne pathogenesis and immune modulation. This study aims to identify compounds from tea leaves (Camellia sinensis var. assamica) that can treat acne by influencing the expression of inflammatory-related genes through in silico analysis. The GSE6475 dataset was utilized to identify differentially expressed genes (DEGs) between acne-affected and normal skin samples (each group n=6). A total of 573 DEGs were identified and mapped to the KEGG inflammatory pathway. The hub gene analysis results showed six genes, including CXCL1, STAT1, and PIK3 (adj. P-value < 0.05). These key genes were then used to cross-validate skin grouping with acne lesions and normal skin. The structure of compounds (natural products) in tea leaves (C. sinensis var. assamica) was obtained from the PubChem database, and their activity against target proteins associated with the identified key genes was predicted using the SkelSpheres descriptor and Support Vector Regression method. This quantitative structure–activity relationship (QSAR)-based machine learning approach was selected because it enables high-throughput prediction of inhibitory potential using chemical descriptors and experimentally derived bioactivity data, providing broader predictive power than conventional molecular docking or molecular dynamics, which rely mainly on structural and energetic estimations. The in-silico prediction results showed that compounds such as theobromine, assamsaponin, procyanidin, and caffeine have exhibited good predicted activity (IC₅₀ ranging from 1.125 to 1.320 μM) as potential inhibitors of the PI3K/Akt pathway, which is known to play a role in the pathogenesis of acne.
Copyright (c) 2025 La Ode Sumarlin, Siti Nurbaya, Meyliana Wulandari, Syed Azhar Syed Sulaiman https://creativecommons.org/licenses/by-sa/4.0
Exploring Brazilin as a Potential Breast Cancer Therapy via Molecular Dynamics Simulation Targeting ERα, 17β-HSD1, and NUDT5 Receptors
Breast cancer remains one of the leading causes of cancer-related mortality worldwide, suggesting the need for novel therapeutic agents with greater efficacy and fewer side effects. Brazilin, a natural flavonoid compound isolated from Caesalpinia sappan L., has shown promising anticancer activity, particularly against breast cancer cells. This study explores the therapeutic potential of brazilin by evaluating its interactions with three key molecular targets: estrogen receptor alpha (ERα), 17β-hydroxysteroid dehydrogenase 1 (17β-HSD1), and Nudix hydrolase 5 (NUDT5). Using molecular dynamics (MD) simulations, the study assesses the stability and binding interactions of complex systems. The results indicate that brazilin forms a stable complex with ERα, demonstrated by a low RMSD (2.6 Å) and strong hydrogen bonding with Glu353, occupancies of 97.8%, and minimal flexibility at the binding site (average RMSF < 2.5 Å). The binding free energy (ΔG Total) for the ERα–brazilin complex was -54.28 kcal/mol, indicating a stronger affinity than the reference ligand 4-hydroxytamoxifen. Brazilin also showed favorable binding with 17β-HSD1 and NUDT5, with binding energies of -39.71 kcal/mol and -23.23 kcal/mol, respectively. These findings suggest that brazilin may modulate critical targets involved in breast cancer progression, particularly in hormone receptor-positive subtypes. Further experimental validation is necessary to confirm its efficacy and optimize its therapeutic potential.
Copyright (c) 2025 Umi Baroroh; Jasmine Aulia Dasilva; Melvia Sundalian, Dewi Astriany, Arif Nur Muhammad Ansori, Jonie C. Yee https://creativecommons.org/licenses/by-sa/4.0
Exploration of Tempeh and Kidney Bean (Phaseolus vulgaris) Biscuits as Inhibitors of Angiotensin-Converting Enzyme (ACE-I)
The study aims to improve the nutritional value of biscuits made from wheat flour and red kidney bean tempeh flour to functional antihypertensive biscuit as functional food by inhibiting angiotension-converting enzyme (ACE-I). Kidney beans were fermented for 32 hours at room temperature using 0.2% tempeh yeast. The tempeh was dried and ground using blender, filtered through a 100-mesh sieve. Kidney bean tempeh flour was then mixed with wheat flour in ratios of 40:60, 50:50, 60:40, 70:30, and 80:20.The dough was mixed with eggs, margarine, butter, and sugar, then baked in an oven. Organoleptic tests showed that panelists preferred biscuits 70:30 ratio of kidney bean tempeh flour to wheat flour, with texture, color, and aroma scores all above 3.The highest ACE-inhibitory activity 95.58% was observed in biscuits with an 80:20 ratio. Maillard reaction products in the biscuits contributed to increased ACE-I activity. Peptides of kidney bean tempeh are believed to play an active role in lowering blood pressure in vitro. Total phenolic and flavonoid contents were 0.025 mg GAE and 0.323 mg QE/g, respectively. These compounds also enhanced ACE-inhibitory properties. Based on the research, biscuits made from kidney bean tempeh flour show promising potential for development as functional antihypertensive food.
Copyright (c) 2025 Sri Yadial Chalid, Siti Nurbayti, Safira Ramadhani, Anna Muawanah, Sandra Hermanto, Tarso Rudiana https://creativecommons.org/licenses/by-sa/4.0
Decolorization of Reactive Black 5 by Myceliophthora thermophila KLUM1
This research aimed to ascertain the impact of alkaline lignin of teak sawdust on the synthesis of ligninase and decolorization of Reactive Black 5 (RB5) by M. thermophilia KLUM1, also to elucidate the mechanism of mycoremediation. This research was conducted within the cultivation of the spore suspension in a co-culture setting. The RB5 dye percentage decolorization and ligninase activity were produced by varying the addition of alkaline lignin. The results show that the addition of 0.5% alkaline lignin accelerates the production of ligninase in the Kirk medium. However, adding more than 0.5% alkaline lignin does not affect the highest amount of ligninase produced. The increase in RB5 dye decolorization by M. thermophila KLUM1 is proportional to the increase in alkaline lignin in the medium. The percentage of wood-rot fungi decolorization in Kirk medium with and without lignin with the addition of 0.5%, 1%, and 2% lignin on the 10th day was 26.29%, 29.51%, 34.74%, and 40.43%, respectively. The decolorization process of RB5 by M. thermophilia KLUM1 in Kirk medium with alkaline lignin occurs through several mechanisms, i.e., enzymatic degradation, adsorption by the growing mycelia, and alkaline lignin present in the medium.
Jurnal Kimia VALENSI, Volume 11, No. 1, May 2025
Copyright (c) 2025 Evi Susanti, Rizky Febriani Jati, Dwi Apriani, Suharti Suharti, Mieke Alvionita https://creativecommons.org/licenses/by-sa/4.0
TiO2/Zeolite Coal Fly Ash Nanocomposite for Photodegradation of Naphthol Blue Black Dye: Optimization and Mechanism under Visible Light
Naphthol Blue Black (NBB) is a water-insoluble synthetic azo dye with a molecular weight of 616.49 g/mol that requires alkaline treatment for solubility and poses environmental risks by reducing water quality, increasing BOD and COD, and disrupting aquatic ecosystems. The TiO₂/Zeolite Fly Ash nanocomposite represents a promising material for the photocatalytic degradation of NBB. Analysis of the TiO2/zeolite fly ash nanocomposites revealed the presence of Ti-O-Si and Ti-O-Al functional groups, along with a suitable band gap energy value of 2.85 eV for visible light consumption. The average particle size is 62-75 nm, with a relatively high crystallinity of 95.64%. The insertion of TiO2 into the surface of the zeolite changes the size of the catalyst from 62-75 nm to 10 nm and 98.2% crystallinity. An emphasis was placed on the key parameters governing the degradation process. The test results showed that the degree of degradation increases at lower pH, while changes in catalyst dosage and initial dye concentrations do not significantly affect the degradation of NBB. The addition of H2O2 demonstrates the increasing degradation efficiency. The optimum operating process was carried out by adding 1.2 % (v/v) of H2O2, the pH 2, 0.1% (w/v) of catalyst, an initial concentration NBB of 12 mg/l, and irradiating under visible light for 75 minutes. It was a short period to produce the best conditions for degrading 12 mg/l naphthol blue-black, with a degradation efficiency of 99.68%. The rate of photodegradation kinetics had a reaction rate constant of 0.0312 min-1 and was followed a pseudo-first-order Langmuir-Hinshelwood. From the results, it was found that adsorption is an essential factor in the photodegradability of the dye. The linear transform of the Langmuir isotherm curve was further used to determine the characteristic parameters, which included the maximum absorbable dye quantity Qmax=11,8217 mgg-1. LC-MS/MS analysis identified the compounds formed through the photocatalytic degradation of naphthol blue-black dye into lower-molecular-weight molecules, such as benzoic acid, maleic acid, and phenol, which can gradually break down naturally into carbon dioxide and water.
Copyright (c) 2025 Linda J Kusumawardani, Yulian Syahputri, Muhammad Fathurrahman, Apriyansyah Apriyansyah https://creativecommons.org/licenses/by-sa/4.0
Efficacy Test of Prototype Kit for Detection Bacillus cereus and Listeria monocytogenes in Processed Meat using Real-time PCR Method
According to the World Health Organization (WHO), harmful agents such as Bacillus cereus and Listeria monocytogenes are responsible for 600 million cases of disease and 420,000 deaths annually. This research aims to test the effectiveness of the real-time PCR method for developing a prototype kit to detect pathogenic bacteria in processed meat. As a comparison, the and conventional PCR methods were used to obtain the accuracy, specificity, sensitivity, and effectiveness of the real-time PCR method. All the samples were cultured in solid media agar, performed amplification using specific primers cyt-K 2 and hly using PCR and real-time PCR. Meatballs, nuggets, and sausages, five samples each, were found to be positive positively contaminated with all targeted bacteria. However, they did not provide specific results using solid media culture and the PCR method. In addition, the real-time PCR method using prototype kit formulas accomplished that all contaminated samples had a Ct value smaller than the negative control, NTC (No Template Control), and had a similar melting curve to the positive control. This establishes that the real-time PCR method clarifies that all samples were contaminated with target bacteria. A formula was developed in the prototype kit with real-time PCR methods that can be used and applied on a commercial scale efficiently and precisely.
Copyright (c) 2025 Muktiningsih - Nurjayadi, Tiara Fahriza, Adinda Myra Amalia Putri, Atikah Nur Rahmawati, Ayu Berkahingrum, Rosita Gio Anggraeni, Gladys Indira Putri, Jefferson Lynford Declan, Dandy Akbar, Irvan Maulana, Maharanianska Azzahra, Muhammad Arkent Shangkara, Irma Ratna Kartika, Fera Kurniadewi, Dalia Sukmawati, Sri Rahayu, Vira Saamia, I Made Wiranatha, Bassam Abumoelak, Hesham A El Enshasy https://creativecommons.org/licenses/by-sa/4.0
Isolation of Endophytic Pseudomonas Strains from Papaya Leaves and Their Extracellular Enzyme Production and Antioxidant Profile
Endophytic bacteria, symbiotic microorganisms residing in plant tissues, produce bioactive compounds similar to host plants, such as antioxidants. These antioxidants are crucial in combating free radicals linked to degenerative diseases. This study isolates and characterizes two endophytic bacterial strains from papaya leaves, exploring their enzymatic and antioxidant activities. Two isolates of endophytic bacteria from papaya leaves were obtained, F1-A and F1-B. F1-A endophytic bacteria are types of monobacilli, Gram-positive bacteria. F1-B endophytic bacteria are types of Bacilli. Using 16S rRNA analysis, both isolates were predicted to belong to the Pseudomonas bacterial strain. Research on optimizing their growth under various temperatures and pH conditions showed that both isolates grow best at 37°C. F1-B provides a better opportunity as a source of industrial enzymes because it can excrete amylase, urease, cellulose, and protease enzymes compared to F1-A, which can only produce amylase and protease enzymes. Nevertheless, F1-A can act as a potent antioxidant with an IC50 of 34.18 ppm compared to F1-B, which has an IC50 value of 292.31 ppm. The IC50 value of the F1-A isolate was not much different from the IC50 of quercetin, which was 12.50 ppm. The ability of F1-A as an antioxidant is also influenced by the results of phytochemical screening, which can contain more secondary metabolites than F1-B. These results highlight the potential of Pseudomonas strains as sources of industrial enzymes and natural antioxidants, warranting further investigation.
Copyright (c) 2025 Purbowatiningrum Ria Sarjono https://creativecommons.org/licenses/by-sa/4.0
A Novel Benzenesulfonylurea-Substituted Pyridazinone Derivative with Antidiabetic Effect as the Peroxisome Proliferator-activated Receptor (PPAR-γ) Agonist
Peroxisome Proliferator-activated Receptor (PPAR-γ) protein is one of the target proteins for insulin sensitivity therapy in Type 2 DM. PPAR-γ has a key role as a nuclear receptor that regulates the expression of several metabolism-related genes. This research aims to synthesize a novel benzenesulfonylurea-substituted pyridazinone derivative, namely (E)-N'-(1-(4-(3-(4-methoxyphenyl)-6-oxopyridazin-1(6H)- yl)phenyl)ethylidene)-4-methylbenzenesulfonohydrazide (8) and predicted it activity as the PPAR-γ agonist using a molecular docking approach and ADMET profiles. The compound 8 was obtained through a Schiff base condensation reaction between compound 6, p-tosyl hydrazine, and a glacial acetic acid catalyst using monowave. The purity of the compound was determined by TLC test, and melting point measurement. The structure was confirmed through FTIR, 1H-NMR, C-NMR and HRMS analysis. Molecular docking studies were carried out on the crystal structure of the human PPAR-γ Ligand Binding Domain target protein in complex with the α-aryloxyphenyl acetic acid agonist (PDB ID 1ZEO). The results of the docking show that compound 8 has a lower binding free energy than rosiglitazone (positive control) with a free energy value (S score) = -13.513 kcal/mol and -8.3089 kcal/mol, respectively. Compound 8 can form two hydrogen bonds with residues His323 and Ser289, π-π interactions with Phe363 and π-H interactions with Cys285. The interactions are similar to the interaction between the native ligand agonists α-aryloxyphenyl acetic acid and rosiglitazone with the target protein. Furthermore, compound 8 is predicted to have a moderate ADME profile. The results support that compound 8 can be developed as a PPAR-γ agonist candidate for the antidiabetic therapeutic agent.
Copyright (c) 2025 Yuni Fatisa, Elvi Yenti, Arif - Yasthophi https://creativecommons.org/licenses/by-sa/4.0
Isolation and Structural Characterization of Biflavonoids from Araucaria hunsteinii and Araucaria columnaris: Chemotaxonomic and Pharmacological Perspectives
Biflavonoids are a distinctive class of dimeric flavonoids known for their diverse biological activities and chemotaxonomic significance. In this study, two biflavonoids were isolated from the acetone extracts of Araucaria hunsteinii twigs and Araucaria columnaris leaves collected from Bogor Botanical Garden, Indonesia. Chromatographic techniques, including Sephadex LH-20 column chromatography and preparative thin-layer chromatography, were employed for purification, followed by structural elucidation using LC-MS/MS and 1D/2D NMR spectroscopy. The compounds were identified as 4',4''',7,7''-tetra-O-methylcupressuflavone (1) and 7-O-methylcupressuflavone (2). Notably, this is the first report of 7-O-methylcupressuflavone isolated from A. columnaris leaves, providing new chemotaxonomic insights into the genus Araucaria. A literature-based pharmacological analysis revealed promising cytotoxic and α-glucosidase-inhibitory activities of the isolated compounds. These findings contribute to the phytochemical profiling and highlight the pharmaceutical potential of Araucaria-derived biflavonoids.
chemotaxonomy 4′,4‴,7,7″-tetra-O-methylcupressuflavone
Copyright (c) 2025 Purwantiningsih Sugita https://creativecommons.org/licenses/by-sa/4.0
Papain-like Protease Peptides as Construction Material for the SARS-CoV-2 Vaccine Design Candidate: In-silico Study
COVID-19 remains a major global health threat. In addition to implementing health protocols and consuming supplements, proactive prevention strategies are essential to limit the spread of the virus. One of the most promising approaches is the use of vaccines, particularly peptide-based vaccines, which are under active development. This study aimed to design a peptide vaccine derived from the SARS-CoV-2 papain-like protease (PLpro) and evaluate its interaction with key components of the human immune system, namely Toll-like receptor 3 (TLR3), major histocompatibility complex class I (MHC-I), and class II (MHC-II). The research employed an immunoinformatics approach utilizing NetCTL, IEDB Tepitool, PEP-FOLD3, trRosetta, HDOCK, GalaxyRefine2, and other molecular modeling tools. The designed vaccine construct was visualized in 3D using trRosetta and validated through ERRAT2, achieving a 100% quality score, indicating excellent structural integrity. The docking simulations demonstrated stable interactions between the vaccine and the immune receptors, suggesting strong immunogenic potential. In conclusion, the in silico-designed peptide vaccine based on SARS-CoV-2 PLpro shows promise in triggering immune responses through stable binding with TLR3, MHC-I, and MHC-II, highlighting its potential as a candidate for further experimental validation in COVID-19 vaccine development.
Copyright (c) 2025 Richa Mardianingrum, Nur Ihsani Pertiwi, Lina Rahmawati Rizkuloh, Ruswanto Ruswanto https://creativecommons.org/licenses/by-sa/4.0
Fabrication and Synthesis of Fluorescent Carbon Nanodots from Black Sticky Rice as Probes for detection Mg2+ ions
Herein, fluorescent carbon nanodots (C-dots) with average diameter of 5.51 nm were fabricated from black sticky rice by using carbonization method. These C-dots have been synthesized with magnesium (Mg2+) ions to investigate their potential application as probes for detection Mg2+ ions. The as-obtained C-dots were measured their absorption (Abs), photoluminescence (PL), and FTIR spectra, X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) image. According to their Abs spectrum, the Abs peak at 276 nm confirmed the presence of C-dots in ethanol solution. Fortunately, the PL peak at 427 nm corresponded to their blue emission color. The XRD patterns and the TEM image confirmed also the formation of amorphous state and monodispersed spherical C-dots, respectively. When the as-prepared C-dots were synthesized with Mg2+ ions, the PL intensities of C-dots quenched as increasing the concentration of Mg2+ ions. A characteristic PL quenching of the C-dots through Mg2+ chelation demonstrated the sensing system up to the detection limit of 2.98 µM. This is the first reporting the application of C-dots as sensors for detection Mg2+ ions. These findings can pave the large opportunity for application of these C-dots in sensing, bioimaging, drug delivery, and so on.
Copyright (c) 2025 Zakarias Seba Ngara, Anastasia Mamut, Redi Kristian Pingak, Albert Zicko Johannes, Reinner Ishaq Lerrick, Refli Refli https://creativecommons.org/licenses/by-sa/4.0
Preparation of Pectin Membranes with Polyvinyl Alcohol (PVA) Blended Method as Dialysis Membrane for Urea Transport
Pectin has shown the potential to act as membranes in a variety of applications, such as in biomedical applications such as that carried out in this study. This study aims to modify pectin with polyvinyl alcohol (PVA) for hemodialysis membrane applications. Pectin-PVA membranes were made by immersing the membrane with 4% PVA and tested for the membrane's filtration capacity for transport. Pectin-PVA membranes were tested using Tensile Test, Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermal Test. The results showed that the pectin blended polyvinyl alcohol (PVA) membrane was successfully synthesized, confirmed by the spectra on FTIR there were OH vibrations, –CH2, –CH, -CO (ester) and CO (ether) bonds, PVA will increase the stress and strain value, XRD data shows that the membrane has a crystalline structure, SEM data shows that the membrane including in the microspheres, and the membrane undergoes carbonization at a temperature of around 400 °C there is an increase in the absorbance value, and the urea transport process increases the absorption of urea every hour.
Biomaterial synthesis and medical chemistry
Copyright (c) 2025 Budi Hastuti, Garnish Teantine Aurura Teantine Aurura, Saptono Hadi https://creativecommons.org/licenses/by-sa/4.0
Assessment of Macronutrient Dynamics in a Tropical Watershed: A Study from Bengkulu River and Estuary Indonesia
This study assesses the sources, transport, and distribution of macronutrients, including nitrate, nitrite, silicate, and phosphate, starting from the upper stream of the Bengkulu River, which is the biggest river in Bengkulu Province, to the coastal seawater of the eastern tropical Indian Ocean. The sampling was conducted using an acid-washed polypropylene beaker and placed in acid-cleaned 5 L polyethylene containers during the dry season in July 2024. The water samples were collected from the surface waters of 15 stations. The macronutrients in the water samples were determined using a spectrophotometer UV-Vis following the Strickland and Parsons method. Macronutrient analysis was conducted in LATERIO BRIN, Jakarta, Indonesia. The concentration of analysed macronutrients ranged from 0.005 - 0.058 mgN-NO3/L for nitrate, <0.001 - 0.014 mgN-NO2/L for nitrite, 0.163 - 9.314 mgSi-Si(OH)4/L for silicate, and 0.01 - 0.085 mgP-PO4-/L for phosphate. Several stations, including Stations 6, 10, and 14, exhibited relatively elevated nitrate concentrations, which were further supported by similarly high phosphate levels. Stations 6, 10, and 14, situated near areas of intense anthropogenic activity in Bengkulu City, suggest that human-induced inputs have enriched the water environment with macronutrients. The highest silicate concentration was observed at Station 1, located upstream in the Bengkulu River. This aligns with previous findings and underscores the role of weathering processes in controlling silicate distribution. Compared to the macronutrient concentration guidelines for river water set by Indonesian Government Regulation 2021 No. 22, the nitrite concentrations at certain river stations exceeded the safety threshold for aquatic biota. In contrast, nitrate and phosphate levels remained within the safe range.
Copyright (c) 2025 Wiwit Wiwit, Idha Yulia Ikhsani, Nurhamidah Nurhamidah, Dwita Oktiarni, Kuo Hong Wong https://creativecommons.org/licenses/by-sa/4.0
TLC Fingerprint Analysis and Evaluation of α-Glucosidase Inhibitory and Free Radical Scavenging Activity of Justicia gendarussa from Different Growth Locations
Justicia gendarussa is known to have antioxidant and antidiabetic properties, which are related to the composition and concentration of its metabolites and influenced by differences in growth location. This study aims to evaluate changes in metabolite profiles and biological activities, such as the inhibition of α-glucosidase and free radical scavenging in J. gendarussa genotypes from Bogor, Cianjur, and Sukabumi. Changes in metabolite profiles were assessed using thin-layer chromatography (TLC) fingerprint analysis combined with principal component analysis (PCA). Bioautography TLC using DPPH was performed to confirm the presence of antioxidant compounds. In the TLC fingerprint analysis of J. gendarussa, we obtained 14 bands with good resolution. PCA successfully grouped J. gendarussa extracts based on growth location. The percentage of α-glucosidase inhibitory and free radical scavenging activity was significantly different, with the highest percentage of inhibition of α-glucosidase shown by the IIIS genotype (99.23%) and the highest free radical scavenging (91.35%) demonstrated by the IIB genotype. The results of TLC bioautography confirmed the presence of antioxidant compounds in J. gendarussa represented by bands with Rf 0.04, 0.32, and 0.80. This study concludes that growth location differences influence the variations in metabolite profiles, α-glucosidase inhibitory activity, and free radical scavenging activity of J. gendarussa genotypes.
Copyright (c) 2025 Laela Wulansari, Wulan Tri Wahyuni, Waras Nurcholis, Mohamad Rafi https://creativecommons.org/licenses/by-sa/4.0
Search for SARS-CoV-2 Inhibitors. Is it still needed?Molecular Docking Study of Teicoplanin Derivatives and Vancomycin against SARS-CoV-2 Mpro
Coronaviruses have been known since 2002 in the case of SARS (Severe Acute Respiratory Syndrome). SARS-CoV-2, the cause of the COVID-19 pandemic, is believed to be an evolution of the SARS-causing coronavirus (SARS-CoV). This evolution shows the complex interaction dynamics between the virus and the host, which have characterized the emergence of new SARS-CoV-2 strain variations until now. Therefore, the search for these antiviral drugs is still critical. MPro is one of the important proteins for the life cycle of pathogenic coronaviruses, so it is an attractive target for developing drugs that inhibit this virus. This study examined the interaction of teicoplanin derivatives and vancomycin as SARS-CoV-2 MPro (6LU7) inhibitors through molecular docking with Autodock Vina. The smallest RMSD value was selected and stored to calculate the energy value. The image of atoms in the ligand and receptor was processed with Autodock Tools, LigPlus, and PyMOL. The study showed that teicoplanin derivatives such as teicoplanin aglycone, teicoplanin-A3-1, and vancomycin had the potential as SARS-CoV-2 Mpro inhibitors. Based on the interaction at the active site and the obtained ΔG values, even the teicoplanin aglycon had a more significant inhibitory potential than other potent inhibitors such as N3.
Copyright (c) 2025 Sri Mulyani https://creativecommons.org/licenses/by-sa/4.0
In Vitro and In Silico Study of Antibacterial Activity of Sirih Merah Leaf Extract (Piper crocatum Ruiz & Pav.) Against Streptococcus mutans
Sirih merah leaf (Piper crocatum Ruiz & Pav) is a natural material that has the potential to be used as a natural antibacterial agent in treating dental caries caused by Streptococcus mutans because it is known to contain secondary metabolite compounds that have antibacterial properties that can inhibit the activity of glucosyltransferase and glucan-binding protein (Gbp) enzymes produced by S. mutans. This study was conducted to determine the antibacterial activity of Sirih merah leaf extract against S. mutans using the Kirby-Bauer method and to predict the potential molecular activity of antibacterial compounds contained in Sirih merah leaves in inhibiting the growth of S. mutans bacteria in silico using the molecular docking method. Antibacterial activity testing of Sirih merah leaf extract fractions obtained from methanol extract showed that fractions 7 and 10 are active fractions because they can inhibit the growth of S. mutans at the highest concentration of 10% with a strong inhibition zone category. The active fractions were then analyzed by the LC-HRMS method to obtain active compounds. The results of the in silico molecular docking test showed that the active compounds of Sirih merah leaves have the potential to interact with the GtfB and GbpC enzymes of S. mutans, where the best binding energy in the interaction of cafedrine compounds is -8.75 kcal/mol and -9.27 kcal/mol. The docking results were validated through a molecular docking process using native ligands with RMSD values of 1,861 Å and 3,170 Å.
Copyright (c) 2025 Trisna Yuliana https://creativecommons.org/licenses/by-sa/4.0
Fabrication of Calcite Calcium Carbonate from Eggshells Biogenic Waste Through Carbonation Method
Calcium carbonate derived from eggshells has significant potential for use in drug delivery systems, pharmaceutical, food, catalyst, cement, and concrete industries. Although eggshell waste is non-toxic, its excessive accumulation in the environment may contribute to ecological issues. Colonizing pathogenic bacteria in unprocessed eggshell waste poses a potential health risk. The present study outlines the production of precipitated calcium carbonate (PCC) from eggshell waste through a calcination-carbonation process, offering a sustainable approach to its utilization. The calcination was carried out at 900 ºC. The carbonation process was performed in an HNO3 solution, and the NH3 solution was under-treated for 60 minutes. The results exhibited that the precipitated calcium carbonate (PCC) had a purity of 95.2% CaO. It possessed predominantly the calcite phase with a rhombohedral crystal system, as confirmed by the XRD analysis. The crystallite size of PCC was 109.5 nm, measured using the Debye-Scherrer equation. The phase composition of PCC was 99.3% calcite, 0.5% vaterite, and 0.2% aragonite. FTIR analysis further corroborated this data by showing a sharp and unsplit peak at 1419 cm-1, demonstrating the presence of a calcite phase. SEM images revealed a cubic-like morphology, a characteristic of the calcite form of calcium carbonate (CaCO3). The synthesized calcium carbonate in this study holds potential for applications in dental materials and as fillers in polymer matrices for food packaging.
Copyright (c) 2025 Mariyam Mariyam https://creativecommons.org/licenses/by-sa/4.0
Natural Zeolite as Mo and MoP Catalysts Support for Catalytic Deoxygenation of Jatropha Oil
Non-edible oil, such as Jatropha oil, is an interesting feedstock for the development of renewable diesel (green diesel). Catalytic deoxygenation using natural zeolite-supported Mo-based catalysts is a promising process for the conversion of Jatropha oil to green diesel. Mo and MoP catalysts supported on natural zeolite were synthesized by wet impregnation at a concentration of 5% (w/w). The catalysts were characterized by XRD, XRF, SAA and NH3-TPD. The catalysts were successfully synthesized with the appearance of Mo and MoP peaks on the catalyst diffractogram. XRF results also showed that Mo and P were present in the catalyst. Metal impregnation decreased the surface area and pore volume of the catalyst, but increased the average pore diameter. The NH3-TPD profile of the catalyst showed that the weak acid sites of both catalysts were larger than the strong acid sites. Based on the activity test of catalytic deoxygenation of Jatropha oil, the MoP/HZ catalyst produced a higher conversion (67%) and liquid product yield (79%) than Mo/HZ. This is associated with a larger pore diameter, so that the distribution of reactants on the catalyst surface is more optimal. However, the highest green diesel selectivity of 82% is produced by the Mo/HZ catalyst. The Mo/HZ catalyst is more oriented towards the HDO reaction, whereas the MoP/HZ catalyst is more oriented towards the DCO/DCO2 reaction.
Copyright (c) 2025 Isalmi Aziz https://creativecommons.org/licenses/by-sa/4.0
Discriminating Green Beans of Puntang Arabica Coffees with 1H NMR Based-Metabolomics
Puntang Arabica Coffee is one of the famous Indonesian coffees from West Java. This coffee is cultivated in the area of Mount Puntang, Bandung Regency. This study evaluated green beans of Puntang Arabica coffee obtained from different cultivating locations, including Cimulek, Cimenong, Ganda Paraja, and Nameur, with 1H NMR-based metabolomics. The green coffee bean samples were ground, extracted with D2O, and then measured with NMR spectroscopy. The obtained 1H NMR spectra were processed and evaluated by multivariate data analysis techniques using Orthogonal Partial Least Square Discriminant Analysis (OPLSDA) as the main model. In total, 20 metabolites were successfully identified in the 1H NMR spectra of Puntang coffees. Based on multivariate analysis, Cimulek and Cimenong coffee regions possessed similar metabolite profiles possibly due to being in proximity. Trigonelline, 5-chlorogenic acid, and citric acid were detected as the discriminant compounds for Cimulek and Cimenong coffees, whereas lactic acid, lipids, and stearic acid were associated with Ganda Paraja coffee. Meanwhile, GABA was detected constantly as the characteristic compound of Nameur coffee. This report revealed the metabolite profile of Puntang Arabica coffees for the first time and provided scientific information for the development of coffee plantations.
Copyright (c) 2025 Nizar Happyana https://creativecommons.org/licenses/by-sa/4.0
Synthesis and Antibacterial Activity of Chitosan-Cinamaldehyde/AgNp Schiff Base Composite
Chitosan is a material that has antibacterial properties. Chitosan was modified with cinnamaldehyde to form chitosan Schiff base, which acts as a capping agent in the synthesis of silver nanoparticles. The Schiff base product was modified again into a silver nanoparticle Schiff base composite to improve its ability as a capping agent and improve its antibacterial properties. This study aims to synthesize a chitosan-cinnamaldehyde/AgNP Schiff base composite (CCSB/AgNP) as an active ingredient with excellent antibacterial properties. The first stage was the synthesis of a chitosan-cinnamaldehyde Schiff base. In the second stage, the synthesis of the chitosan/AgNP composite was carried out by adding STPP with sonication and a water bath. The third stage involved synthesizing of the CCSB/AgNP composite using the same method as the second stage employing both heating and non-heating as well as sonication and non-sonication. The product was characterized using a UV-Vis spectrophotometer, FT-IR, SEM-EDX, mapping, and AAS. Antibacterial tests were performed on the synthesized product using the Total Plate Count (TPC) method. Chitosan has a molecular weight of 338080 g/mol and a degree of deacetylation of 65.09%. The Schiff base product of chitosan-cinnamaldehyde is a brownish-yellow solid with a yield of 76.9% (w/w) and a degree of substitution of 87.02%. The presence of Ag was confirmed by EDX mapping, which revealed mass percentages of 0.26%, 1.00%, and 3.97% for C/AgNP-1, C/AgNP-2, and CCSB/AgNP-2, respectively. The chitosan/AgNP product has a yield of 97% (w/w) and an SPR effect at 439 nm. The synthesis of CCSB/AgNP obtained a dark green solid with a yield of 87% (w/w) and an SPR effect at 433 nm. The antibacterial activity test yielded the highest percentage reduction in the number of bacteria in CCSB/AgNP at 3 days of observation at 95.1%, and 7 days at 94.1%.
Copyright (c) 2025 Ismiyarto - Ismiyarto https://creativecommons.org/licenses/by-sa/4.0
Halal Authentication and Metabolite Mapping of Kombucha Products via Gas Chromatography-Mass Spectrometry (GC-MS) and Chemometric Analysis
The presence of ethanol in fermented beverages is a critical factor in the halal certification process. One of the key parameters for verifying the halal status of such products is the quantification of ethanol content. Kombucha tea, a fermented beverage produced from sugared tea and a Symbiotic Culture of Bacteria and Yeast (SCOBY), naturally contains ethanol as a byproduct of fermentation. This study aims to determine the ethanol content and differentiate the metabolite profiles of kombucha tea using a non-targeted metabolomics approach, based on variations in tea type, storage temperature, and duration. Ethanol levels were measured by gas chromatography, and metabolite profiling was conducted by gas chromatography–Mass Spectrometry (GC-MS), followed by Principal Component Analysis (PCA) to visualize compositional differences and identify characteristic compounds. The results indicated that tea type significantly influenced ethanol production. The ethanol content of kombucha prepared with black tea, green tea, and white tea was 0.1126% w/w ± 0.0003 v/v, 0.1708% w/w ± 0.0053 v/v, and 0.1301% w/w ± 0.0043 v/v, respectively. Green tea kombucha, which exhibited the highest ethanol content, was selected for storage analysis. During storage, ethanol levels increased slightly to 0.1789% w/w ± 0.0008 v/v in the first week, followed by a gradual decline to 0.1478% w/w ± 0.0071 v/v by the fourth week. Metabolomic profiling revealed distinct differences in secondary metabolite composition among the three tea variants, as evidenced by non-overlapping PCA groupings. Key discriminant compounds identified included ethyl acetate, ethyl octanoate, ethylamine, and (E)-2-decenal, which are proposed as characteristic markers for kombucha derived from black, green, and white teas. These findings contribute to understanding kombucha’s biochemical diversity and support halal verification through ethanol quantification and metabolite-based authentication.
Copyright (c) 2025 Sandra Hermanto, Della Arginia, Mabrurotul Mustafidah, Ahmad Fathoni https://creativecommons.org/licenses/by-sa/4.0
Phenol Biosensor Development Using Bacillus megaterium And Pseudomonas fluorescens Microbes Consortium
Phenol is a toxic industrial pollutant that must be monitored at a low cost and in real-time. Conventional amperometric biosensors based on a single enzyme or a single microorganism often suffer from limited sensitivity and operational drift. Here, we report a microbial consortium biosensor that couples Bacillus megaterium, which supplies phenol-degrading enzymes and structural stability, with Pseudomonas fluorescens, whose electroactive biofilm enhances electron transfer to a screen-printed carbon electrode (SPCE). The electrode potential was swept at 100 mV s⁻¹ between –1 V and +1 V (i.e., a 2 V window traversed in 20 s) to capture the full redox range of phenol by Cyclic Voltammetry (CV). The oxidation peak current grew linearly with phenol concentration from 27 to 137 mg/L (R² = 0.98), giving a sensitivity of 1.30 µA mg/L and a limit of detection of 13.6 mg/L. Compared with our previously tested single-microbe sensors, the consortium lowered the LOD threefold while maintaining long-term signal stability (>30 days). These results demonstrate that complementary metabolic pathways and the conductive biofilm of P. fluorescens synergistically enhance the electrochemical response provided by B. megaterium. The consortium-based SPCE platform, therefore, offers a robust, inexpensive tool for on-site phenol monitoring in environmental and industrial settings.
Copyright (c) 2025 Reza Mulyawan, Dyah Iswantini, Novik Nurhidayat, Deden Saprudin, Henny Purwaningsih https://creativecommons.org/licenses/by-sa/4.0