ABSTRACT. Corncob is one of agro-food by-products, a potential source of natural antioxidants and functional food ingredients, rich in ferulic acid and dietary fibre. In this study, ferulic acid was isolated from corncobs after alkaline pretreatment using a multi-step extraction process and structurally verified, providing a suitable bioactive compound for baruk sago (SB) starch complexation. FTIR analysis showed characteristic absorption peaks at 3379-3387 cm⁻¹, indicating interactions between FA and starch. XRD results revealed a transformation of the native SB starch crystalline structure and a marked decrease in crystallinity from 40.31% to 8.60% after complexation. SEM observations demonstrated morphological changes from predominantly smooth, oval, and compact granules to a looser gel structure in the starch–FA complex. In vitro antioxidant evaluation using the DPPH radical scavenging assay showed that the SB starch–FA complex exhibited higher scavenging activity compared to native SB and pre-gelatinized (SBG) starch. These findings confirm the successful incorporation of FA into SB starch and demonstrate that complexation significantly modifies physicochemical properties and enhances antioxidant capacity, highlighting its potential application as a functional food ingredient and nutraceutical material. Keywords: Antioxidant, characterization, sagu baruk, starch-ferulic acid complex
ABSTRACT. Diabetes mellitus remains a global health challenge, necessitating the development of more effective a-amylase inhibitors with fewer side effects than current synthetic drugs. This study reports the successful synthesis of three aminated eugenol derivatives, a (1-(4-allyl-2-methoxyphenoxy)-3-(phenylamino)propan-2-ol), b (1-(4-allyl-2-methoxyphenoxy)-3-(m-tolylamino)propan-2-ol), and c (1-(4-allyl-2-methoxyphenoxy)-3-((4 chlorophenyl)amino)propan-2-ol), via ultrasonically assisted epoxide ring-opening using aniline, m-toluidine, and 4-chloroaniline. Ultrasonic irradiation significantly reduced the reaction time from 5-24 hours to 2 hours. Structural characterization by FTIR, ¹H-NMR, ¹³C-NMR, GC-MS, and melting point analysis confirmed the successful formation of all derivatives. In vitro α-amylase inhibition assays (UV–Vis) showed that all compounds exhibited higher inhibitory activity than acarbose, with compound b demonstrating the strongest inhibition (99.04% at 250 µM). Molecular docking studies against α-amylase (PDB: 1B2Y) further supported these results, yielding binding energies of –4.58, –5.13, and –5.16 kcal mol⁻¹ for compounds a, b, and c, respectively, compared with –3.64 kcal mol⁻¹ for acarbose. These findings demonstrate the enhanced efficiency of the ultrasound-assisted synthesis and substituent variations enhance both the structural and biological properties of the eugenol derivatives, offering critical perspectives on how their molecular structure dictates activity, thereby validating their future utility as promising antidiabetic drug candidates. Keywords: α-amylase binding affinity, epoxide ring-opening, sonochemical synthesis, structure-activity relationship, substituent electronic effect.
ABSTRACT. Caffeic acid, a well-studied phenolic acid, has been extensively investigated for its diverse bioactivities, including antidiabetic, anti-inflammatory, antioxidant, antimicrobial, and antiviral properties. Esterification of caffeic acid has been explored to modulate its physicochemical and biological properties, however, optimization of lipophilicity while maintaining inhibitory activity remains a challenge. In this context, citronellyl caffeate was designed as a structurally optimized derivative that enhances α-glucosidase inhibition while improving lipophilicity and permeability. To enhance antidiabetic bioactivity through α-glucosidase inhibition, caffeic acid and citronellol were coupled using dicyclohexylcarbodiimide (DCC) as an activator and 4-dimethylaminopyridine (DMAP) as a catalyst with dimethylformamide (DMF) as the solvent. The synthesis was carried out under reflux conditions, followed by purification via liquid–liquid extraction and column chromatography, with thin-layer chromatography (TLC) used to confirm purity. The resulting compound, citronellyl caffeate, was characterized using ¹H NMR and ¹³C NMR spectroscopy. Evaluation through α-glucosidase inhibition assays demonstrated that citronellyl caffeate showed enhanced α-glucosidase inhibitory activity (IC₅₀ = 31.17 µg/mL) compared to its precursors, caffeic acid and citronellol, despite being less potent than quercetin (IC₅₀ = 2.43 µg/mL), it demonstrates biologically relevant inhibition consistent with successful structural optimization. Keywords: antidiabetic, caffeic acid, citronellol, glucosidase, synthesis
ABSTRACT. The demand for essential oils has increased rapidly in line with the growth of the cosmetic, food, perfume, pharmaceutical, and aromatherapy industries. Citronella essential oil is one of the essential oils with high economic value and significant therapeutic benefits. Its main active constituents—citronellal, citronellol, and geraniol—exhibit antibacterial, antiseptic, and antioxidant activities and are widely utilized in the perfume and cosmetic industries. Despite established quality standards (SNI 06-3953-1995), many commercial products fail to meet required specifications, particularly in active compound content. Previous reports have highlighted variability in citronellal and geraniol levels, raising concerns about product consistency and consumer safety. Therefore, this study aimed to evaluate the conformity of commercial citronella oils and to identify their chemical constituents using GC–MS method. Gas Chromatography–Mass Spectrometry (GC–MS) method allows to detect trace adulterants and confirm the precise chemical and botanical profile of the essential oil. A Total of six citronella essential oil samples were analyzed, consisting of three brands registered with the Indonesian Food and Drug Authority (BPOM) and three unregistered brands. Quality assessments included color, specific gravity, refractive index, solubility in ethanol, and the presence of foreign substances based on the Indonesian National Standard (SNI) 06-3953-1995. The results showed that all samples met the SNI quality requirements, exhibiting pale yellow to yellowish-brown coloration, specific gravity values of 0.8850–0.9127, refractive indices of 1.467–1.474, and clear solubility at a 1:2 ethanol ratio. GC–MS analysis identified dominant compounds such as cyclofenchene, citronellal, and geraniol, with cyclofenchene being the most abundant component. However, despite compliance with physicochemical parameters, the contents of citronellal and geraniol were still below the minimum limits specified by SNI. These findings indicate variations in the quality of commercial citronella essential oils and highlight the need for standardized production processes and continuous quality control. Keywords: Essential oil, GC-MS, kaffir lime, lemongrass
ABSTRACT. Indonesia has a lot of Natural Zeolite potential, one of which is Ende’s natural zeolite(EZ) from Nusa Tenggara Timur Province, which is known to have the main components of mordenite, clinoptilolite, and quartz. EZ can be used as an adsorbent for Crystal Violet(CV) dye waste, which is often used as a dye in the textile industry, veterinary medicine, and dermatology, that can be teratogenic, carcinogenic, and mutagenic. EZ were then tested under three conditions: 100 mesh size(EZ), nano-modification with planetary milling using alumina balls (200 rpm/12 hours)(EZN), and recrystallization(EZM). Each EZ were characterized by XRF, FTIR, SEM, XRD, and Zeta Potential measurements. Optimum conditions for CV adsorption using 0.01 gram of each EZ were achieved at pH 6 and a contact time of 90 min using a volume of 10 mL solution, with the batch method. The CV adsorption process followed the pseudo-second-order adsorption kinetics model and the Langmuir isotherm model with a maximum adsorption capacity of 151.327 mg/g and an R2 value = 0.9635 for EZ, 74.166 mg/g and an R2 value = 0.9128 for sample EZN and a capacity the maximum adsorption was 311.357 mg/g and the R2 value = 0.9752 for sample EZM. The thermodynamic study indicated that the process was spontaneous and endothermic and that the degree of orderliness of the system increased. Keywords: Adsorption, Crystal Violet, Mechanochemistry, Natural Zeolite.
