Acta Chimica Asiana

Synthesis and characterization of Fe3O4-activated charcoal composite of Ihau fruit peel (Dimocarpus longan var. malesianus Leenh.) as methylene blue adsorbent

Azizah Fithri Ananda, Teguh Wirawan, Nanang Tri Widodo — Fri, 28 Nov 2025 00:00:00 +0800

Research has been conducted on the synthesis and characterization of Fe3O4-active charcoal composite of ihau fruit peel (MAACI) as a methylene blue dye adsorbent. This research aimed to produce activated charcoal from ihau fruit peel (AACI) composited with magnetite (Fe3O4). AACI was prepared by carbonating Ihau fruit peel in a furnace at 425C for 1 hour and chemically activated by immersion in an HCl solution for 24 hours. The synthesis of MAACI was carried out using the coprecipitation method with FeCl3 • 6H2O and FeSO4 • 7H2O in a 3:2 ratio, followed by compounding with AACI. The MAACI was characterized by Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The characterization results showed that the FTIR spectrum exhibits an absorption peak at a wavenumber of 586.36 cm-1, indicating the presence of the Fe-O group. SEM analysis revealed that the MMACI has denser pores and a coarser texture compared to activated charcoal. Meanwhile, XRD results showed a diffraction pattern that matches the characterization of magnetite (Fe3O4). The adsorption of methylene blue by MAACI yielded optimum results at a pH of 9 with a contact time of 45 minutes. The maximum adsorption capacity obtained was 8.7014 mg/g, and the adsorption process followed the Langmuir isotherm model. This adsorption takes place spontaneously, is endothermic and occurs physically.

Synthesis and characterization of silver nanoparticles using Ocimum gratissimum root extract and their biological activities against some clinical pathogens

Chioma Mercy Nzerema, Prince Joe Nna, Kingsley John Orie — Fri, 28 Nov 2025 00:00:00 +0800

This study investigates the green synthesis of silver nanoparticles (AgNPs) using Ocimum gratissimum root extract, along with their characterization and antibacterial efficacy. Proximal analysis revealed low moisture (8.02 ± 0.11%), crude protein (3.31 ± 0.28%), crude fat (2.01 ± 0.59%), moderate fibre (9.18 ± 0.40%), and ash (5.11 ± 0.91%), indicating a carbohydrate-rich composition. AgNPs were synthesized using the root extract as reducing and stabilizing agent; UV–Vis spectroscopy confirmed their formation with a surface plasmon resonance peak at 425 nm, consistent with spherical nanoparticles (30–100 nm). FTIR identified phenolic and polysaccharide functional groups (O–H, C=O, C–O), while XRD indicated a face-centered cubic (FCC) structure with good crystallinity. SEM micrographs showed mostly spherical particles with minimal aggregation. Antimicrobial activity at 10–20 mg/mL was tested against Proteus mirabilis, Pseudomonas aeruginosa, Bacillus cereus, Aspergillus fumigatus, Candida albicans, and Saccharomyces cerevisiae. The root extract alone showed no activity at 10 mg/mL but exhibited dose-dependent inhibition at higher concentrations (ZOIs: 10.40–15.16 mm). AgNPs displayed stronger broad-spectrum efficacy (ZOIs: 7.12–18.9 mm), often surpassing gentamicin. These findings highlight the potential of O. gratissimum root-derived AgNPs as eco-friendly antibacterial agents against multidrug-resistant organisms.

Optimization of microwave irradiation time for KOH-activated carbon from oil palm fronds

Rahmat Zikri, Ayu Sapitri, Yolanda Rati — Fri, 28 Nov 2025 00:00:00 +0800

Activated carbon is a widely applied adsorbent material in wastewater treatment, whose physical and chemical properties are strongly influenced by the activation method employed. Microwave irradiation–based physical activation has emerged as an attractive alternative, offering shorter processing times and lower energy consumption compared to conventional heating methods. This study aims to evaluate the effect of varying microwave irradiation times on the characteristics of activated carbon derived from oil palm fronds (OPF) waste. The synthesis process began with carbonization at 600 °C for 60 minutes to produce OPF char, followed by chemical activation using KOH with a char-to-KOH mass ratio of 1:1 (g/g) in 100 mL of demineralized water, and subsequently physical activation using a microwave at 200 W for 5 minutes (A5D200), 10 minutes (A10D200), and 15 minutes (A15D200). Characterization was conducted in accordance with SNI 06-3730-1995 standards (moisture content, ash content, and iodine adsorption capacity), as well as physicochemical analyses including crystallinity, surface area, functional groups, morphology, and elemental composition. The results demonstrated that all samples met the SNI requirements, with the highest iodine adsorption capacity (828.69 mg/g) and the largest surface area (824.26 m²/g) obtained at A10D200. XRD analysis revealed the dominance of amorphous structures with an increasing Lc/La ratio as the irradiation time increased, while SEM images showed relatively small and uniformly distributed pores. FTIR spectra confirmed the presence of O–H, C=O, C=C, C–H, and C–O functional groups. In conclusion, a 10-minute irradiation time produced activated carbon with an optimal balance between pore structure, surface area, and adsorption capacity

Molecular docking study of mutant levansucrase (E342A) from Bacillus subtilis as a receptor for D-glucopyranose and β-D-fructofuranose ligands

Fri, 28 Nov 2025 00:00:00 +0800

Molecular docking is a widely applied computational approach for predicting the binding modes of small-molecule ligands within the active site of a target protein. This research investigated the interactions of mutant levansucrase E342A from Bacillus subtilis (PDB ID: 1PT2) for β-D-fructofuranose and D-glucopyranose ligands. Using AutoDock Vina, the docking results indicated that β-D-fructofuranose exhibited a higher binding energy of –5.6 kcal/mol, compared to D-glucopyranose with a value of –5.4 kcal/mol, suggesting a more stable interaction. It was supported by the binding interaction analysis of β-D-fructofuranose, which established five hydrogen bonds, including direct interactions with the key catalytic residues Asp86 (2.76 Å) and Asp247 (2.64 Å) that are essential for the enzymatic reaction. In contrast, D-glucopyranose formed four hydrogen bonds, involving Arg360 (3.07 Å) and Glu340 (2.64 Å), with most residues contributing to structural stabilization rather than direct catalysis. These results confirm that β-D-fructofuranose plays a crucial role as a determinant of levansucrase activity in the biosynthesis of levan-type FOS, which are known to exhibit strong prebiotic activity.

Effect of different solvents on antioxidant activity of Euphorbia hirta L. extract

Fri, 28 Nov 2025 00:00:00 +0800

Euphorbia hirta L. is a species of plant renowned for its antioxidant properties. However, the optimal solvent for extracting these bioactive compounds to maximize antioxidant activity had not been systematically identified and compared. Previous knowledge suggested that solvent choice affects yield and efficacy; however, there was a lack of conclusive, comparative data specifically for E. hirta extracts using different solvents. The focus of this work was to investigate how different solvents affected the content of phenolics and flavonoids, as well as the antioxidant effect of E. hirta extract. The aerial part of E. hirta powder was extracted with ethanol, ethyl acetate, and n-hexane to obtain the crude extracts. Folin-Ciocalteu reagent and AlCl3 solution were used to assess the total phenolic and flavonoid contents, respectively. The ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) techniques were used to assess antioxidant activity. The total content of phenolics and flavonoids of E. hirta ethanol extract (127.827 ± 2.609 mg GAE/g extract and 28.507 ± 0.464 mg QE/g extract, respectively) was substantially higher than that of the other extracts (p<0.0001). The findings of the FRAP test exhibited that the E. hirta ethanol extract (48.009 ± 1.873 mg AAE/g extract) had a substantially greater reducing power value (p<0.0001) in comparison to other extracts. The ethanol extract of E. hirta had a considerably lower IC50 value (6.154 ± 0.063 ppm and 9.429 ± 0.183 ppm for DPPH and ABTS assays, respectively, with p<0.0001) than the other extracts. This study found that solvent polarity had a substantial influence on the antioxidant activity of E. hirta extracts, with ethanol being an optimal solvent for the extraction procedure.

In silico screening of azo acetohydrazide derivatives as potential antidiabetic agents through alpha glucosidase inhibition

Fri, 28 Nov 2025 00:00:00 +0800

Type 2 diabetes mellitus is a progressive metabolic disorder marked by persistent hyperglycemia resulting from insulin resistance, insufficient insulin secretion, or a combination of both conditions. A potential therapeutic target for treating this illness is the suppression of the alpha-glucosidase enzyme, which is a key regulator of postprandial glucose absorption and carbohydrate metabolism. This work conducted a thorough in silico analysis to evaluate the efficacy of three synthesised azo-acetohydrazide derivatives (designated compounds C, D, and E) as alpha-glucosidase inhibitors. Pharmacokinetic properties and drug-likeness characteristics were evaluated using the SwissADME platform, while molecular docking simulations were conducted with AutoDockTools against the alpha-glucosidase enzyme structure sourced from the Protein Data Bank (PDB ID: 3W37), utilising acarbose as a reference inhibitor. All three compounds adhered to essential drug-likeness criteria, including those established by Lipinski, Veber, and Ghose, and exhibited advantageous physicochemical characteristics, such as appropriate molecular weight, lipophilicity, topological polar surface area, and aqueous solubility. The compounds were anticipated to have significant gastrointestinal absorption and had no ability to penetrate the blood-brain barrier, suggesting a minimal risk of central nervous system damage. Compound E demonstrated the highest binding affinity among the compounds, with a docking score of –7.80 kcal/mol, and formed multiple stabilising interactions within the enzyme's active region, such as hydrogen bonds, hydrophobic contacts, and electrostatic interactions. This study's novelty is the computational discovery of azo-acetohydrazide scaffolds as inadequately investigated chemical entities with potential antidiabetic properties. These findings establish a theoretical basis for continued development and substantiate future endeavours in the synthesis and experimental validation of these molecules. This study validates the efficacy of structure-based drug design in discovering novel alpha glucosidase inhibitors and identifies compound E as a good candidate for further in vitro and in vivo research in type 2 diabetes treatment.

Degrading colour with magnets: degradation of methylene blue MnOx-Fe3O4 using the photo-fenton method

Fri, 28 Nov 2025 00:00:00 +0800

One practical approach to reducing methylene blue (MB) levels is through the Advanced Oxidation Processes (AOPs) method, which utilizes hydroxyl radicals (•OH) to degrade the colored compounds. AOPs have proven to be a highly efficient technology in treating coloured wastewater, with the ability to produce strong oxidants that break down molecules that are difficult to decompose naturally. One of the widely used AOP technologies is the Fenton heterogeneous catalyst, which is known for its affordable price, ease of reuse, and the fact that it does not produce solid sludge. In this study, MnOx-Fe₃O₄ composites were synthesized using the hydrothermal method with variations in the addition of Fe₃O₄ in ratios of 1:5 and 1:10. Several variables tested in the MB degradation process included the volume of H₂O₂ used (5, 10, and 15 mL), composite contact time, and the effect of pH on degradation efficiency. The results showed that the addition of 5 mL of H₂O₂ to the MnOx-Fe₃O₄ composite significantly increased the degradation efficiency of methylene blue up to 92.54% within 120 minutes, with an optimal pH of 9. The addition of H₂O₂ was shown to accelerate the degradation process, which shows great potential in wastewater treatment applications. In addition, the magnetic properties of the MnOx-Fe₃O₄ composite allow easy separation of the catalyst after the treatment process, thus accelerating and facilitating the recovery and reuse of the catalyst. This degradation process involves the formation of hydroxyl radicals (•OH), which are highly reactive and can efficiently break down MB molecules. Thus, this study demonstrates that the MnOx-Fe₃O₄ composite has the potential to be a highly efficient and environmentally friendly catalyst for treating coloured wastewater. This catalyst is also expected to be reusable in several cycles, making it a sustainable and effective choice in industrial wastewater treatment.

Physically activated corn cob carbon for congo red and methanil yellow removal

Faridatun Sholehah; Rabiatul Adawiyah, Bahrun Bahrun — Fri, 28 Nov 2025 00:00:00 +0800

The conversion of agricultural residues into sustainable adsorbents provides an environmentally responsible pathway for advanced wastewater treatment. In this work, physically activated carbon was synthesized from corncob, an abundant and underutilized agricultural byproduct, through carbon dioxide activation at elevated temperatures. Comprehensive characterization using BET surface area analysis, SEM-EDX, and FTIR confirmed the formation of a highly porous structure with abundant surface functional groups, favourable for dye adsorption. The adsorbent exhibited excellent performance in removing Congo Red (CR) and Metanil Yellow (MY), achieving maximum adsorption capacities of 59.88 mg/g and 30.47 mg/g, respectively. The Langmuir isotherm provides a good description of the equilibrium data, while the kinetic results follow the pseudo-second-order model, indicating that monolayer chemisorption is the dominant mechanism. These findings underscore the potential of corncob-derived activated carbon as a cost-effective, renewable, and high-performance material for sustainable wastewater remediation

Coconut shell charcoal briquettes production using banana corm adhesive

Remi Ayu Pratika, Fery Indradewi Armadany, Fahyuddin — Fri, 28 Nov 2025 00:00:00 +0800

The production of biomass-based briquettes from coconut shell charcoal and banana corm adhesive has been successfully carried out. This research aims to determine whether the banana corm may serve as an adhesive for briquette production from coconut shell charcoal. The concentration of banana corm utilized as adhesive is 10, 20, 30, 40, and 50%. For comparison analysis, this study also employed tapioca flour adhesive with the same concentration. The briquettes adhere to the SNI 01-6235-2000 standard for briquettes. The quality of briquettes is determined based on fixed carbon content and calorific value. The minimum standard calorific value and fixed carbon content are 5000 cal/g and 65%, respectively. Briquettes with a 90:10 ratio (coconut shell charcoal to banana corm adhesive ratio) had the highest calorific value of 7250 cal/g and fixed carbon content of 80.04%. In comparison, the tapioca flour adhesive provides a calorific value and fixed carbon content of 6995 cal/g and 81.09%, respectively. Furthermore, another indicator that determines briquette quality is the content of moisture, ash, and volatile matter. Briquettes with a 90:10 ratio possessed low moisture content (3.55%), ash content (6.45%), volatile matter content (9.96%), and burning rate (0.020 g/sec). This result indicates that the briquettes with a 90:10 ratio exhibit the greatest quality. Briquettes with banana corms adhesive have similar characteristics to tapioca flour, especially in terms of calorific value. As a result, the highlight of this research lies in offering banana corm, which has scientific contribution and future potential as an alternative adhesive in the briquetting process

Gravity column chromatography of n-hexane fraction of Rhizophora mucronata leaves from West Nusa Tenggara and their antioxidant activity

Fri, 28 Nov 2025 00:00:00 +0800

In the last few decades, many diseases have been caused by Radical Oxidative Stress (ROS) or free radicals. Compounds that act as natural antioxidants have been widely developed to counteract these free radicals. Rhizpora mucronata was a mangrove species reported to possess strong antioxidant activity. However, the research is limited to extracts; fractions with more specific compound components have not been explored. The n-hexane fraction of R. mucronata leaves was reported to have high total flavonoid content (TFC). The TFC has a positive correlation with antioxidant activity. Therefore, this study aimed to simplify the compound components in the n-hexane fraction of R. mucronata leaves using gravity column chromatography (GCG) and determine their antioxidant activity. The n-hexane fraction was fractionated using GCG with increasing solvent polarity (n-hexane, chloroform, ethyl acetate, and methanol). The fractions were tested for antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) methods. The fractionation using GCG resulted in 80 fractions. These fractions were grouped based on their thin-layer chromatography (TLC) profiles, resulting in 12 groups of fractions (A-L). Fractions D, F, G, H, J, K, and L, the fractions with enough yield, determined their antioxidant activity using the DPPH and ABTS methods. Fractions D and J tested by the DPPH method had IC50 values of 28.68 ± 1.58 ppm and 9.59 ± 0.39 ppm, respectively. Meanwhile, fractions D and J tested by the ABTS method had IC50 values of 15.10 ± 1.00 ppm and 3.16 ± 0.55 ppm, respectively. Meanwhile, fractions F, G, H, K, and L exhibit antioxidant activity with IC50 values greater than 100 ppm. Fractions D and J have potent antioxidant activity, and both were tested using DPPH and ABTS methods. Therefore, fractions D and J can be further developed as natural antioxidants.

Kombucha tea from ambarella fruit as a natural antibacterial agent against Escherichia Coli and Staphylococcus aureus

Musyirna Rahmah Nasution, Agfa Febriyananda — Fri, 28 Nov 2025 00:00:00 +0800

Kombucha tea is a traditional fermented beverage known for its probiotic benefits, produced from sweetened tea fermented with a Symbiotic Culture of Bacteria and Yeast (SCOBY). Recent innovations have focused on enhancing its functional properties using local fruit extracts. However, studies on the incorporation of Spondias dulcis (kedondong), a native fruit of Riau, remain limited. This study aims to formulate kombucha tea enriched with kedondong juice and evaluate its quality and antibacterial activity against Escherichia coli and Staphylococcus aureus. Four formulations were prepared with kedondong juice concentrations of 0% (F1), 10% (F2), 20% (F3), and 30% (F4). Parameters observed included organoleptic properties, pH, alcohol content, microbial growth, and total acidity. Antibacterial activity was tested using the disc diffusion method, and results were statistically analyzed using One-Way ANOVA. F4 on day 7 showed the highest inhibition zones (13.30 mm for E. coli and 14.49 mm for S. aureus), with significant differences between formulations (p < 0.05). This study highlights the potential of kedondong-enriched kombucha tea as a functional probiotic beverage and a natural source of mild antibacterial agents, offering an innovative approach to utilizing local biodiversity in public health.

Tailoring AlGaN nanoalloys with transition metal dopants for enhanced energy storage: A DFT Study

Fatemeh Mollaamin — Fri, 28 Nov 2025 00:00:00 +0800

The notable fragile signal intensity close to the parallel edge of the nanocluster sample might be owing to silicon or germanium binding induced non-spherical distribution of AlGaSiN or AlGaGeN heteroclusters. However, a considerable deviation exists from doping atoms of palladium or platinum as electron acceptors on the surface of AlGaPdN or AlGaPtN heteroclusters. Then, magnetic parameters exhibited the same tendency of shielding for palladium or platinum; however, a considerable deviation exists from doping atoms of palladium or platinum as electron acceptors on the surface of Pd–AlGaN or Pt–AlGaN hetero-clusters. Therefore, it can be considered that palladium or platinum atoms in the functionalized AlGaPdN or AlGaPtN might have more impressive sensitivity for accepting the electrons in the process of hydrogen adsorption. The advantages of platinum or palladium over aluminum gallium nitride include its higher electron and hole mobility, allowing platinum or palladium doping devices to operate at higher frequencies than silicon or germanium doping devices. As a matter of fact, it can be observed that doped heteroclusters of AlGaPdN or AlGaPtN might ameliorate the capability of AlGaN for energy storage.

Bioactive peptides from traditional homemade fermented foods as an alternative for treatment

Nabella Suraya, Titania Tjandrawati Nugroho, Ismawati Ismawati, Saryono Saryono — Fri, 28 Nov 2025 00:00:00 +0800

Bioactive peptides in fermented foods are attracting scientific interest due to their prospective applications as nutraceutical and functional foods. Conventional fermented foods are naturally processed at home through the action of lactic acid bacteria (LAB). These bacteria break down food components and generate lactic acid, various organic acids, hydrogen peroxide, carbon dioxide, and short-chain peptides, which offer numerous health benefits. The bioactive peptides formed during fermentation exhibit diverse biological functions influenced by their structural compositions. Following enzymatic hydrolysis, peptides initially inactive within the native protein matrix are released and exhibit biological activity. This review aims to comprehensively examine the functional properties of bioactive peptides derived from the fermentation of traditional foods, with a particular emphasis on their therapeutic potential, including antidiabetic, antihypertensive, and anticarcinogenic activities. This review examines the health benefits of various bioactive peptides produced by lactic acid bacteria during the fermentation of traditional foods. Microbial bioactivity during the fermentation process can produce hydrolytic enzymes that break down macromolecules in food into smaller compounds, such as bioactive peptides. A wide range of peptides have been identified as improving insulin uptake, decreasing blood glucose concentrations, and inhibiting key enzymes involved in the pathogenesis of diabetes. Specific peptides exert antihypertensive effects by acting as angiotensin-converting enzyme (ACE) inhibitors, thereby preventing the transformation of angiotensin I into angiotensin II. Moreover, some bioactive peptides demonstrate immunomodulatory properties by enhancing immune responses and inducing apoptosis in cancer cells. This article provides a comprehensive overview of the therapeutic and health-promoting potentials of bioactive peptides derived from fermented foods.