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Yehezkiel Steven Kurniawan
Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara, Yogyakarta 55281, Indonesia
Chemical Engineering, Chemistry & Bioengineering Chemistry

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Synthesis and Kinetic Study of the Urea Controlled Release Composite Material: Sodium Lignosulfonate from Isolation of Wood Sawdust-Sodium Alginate-Tapioca Arif Cahyo Imawan; Yehezkiel Steven Kurniawan; Muhammad Fernadi Lukman; Jumina Jumina; Triyono Triyono; Dwi Siswanta
Indonesian Journal of Chemistry Vol 18, No 1 (2018)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (422.693 KB) | DOI: 10.22146/ijc.26597

Abstract

A synthesis and kinetic study of the urea controlled-release composite material based on isolated Na-lignosulfonate, Na-alginate and tapioca was carried out. This experiment’s aims were to isolate Na-lignosulfonate from wood sawdust and to applicate this isolated Na-lignosulfonate, along with tapioca and Na-alginate as urea control release composite material. A kinetic study of urea released from the composite materials was also conducted. Na-lignosulfonate was isolated by Kraft lignin method to give a brown solid yield of 16.92% and was characterized by FT-IR spectrophotometer and SEM-EDX. The composite materials were synthesized by blending urea as the active compound with composite material as the carrier compound. Three types of material were prepared: complete material (A), low-concentration Na-lignosulfonate material (B) and material without tapioca (C). The composite material had a spherical form with 0.79 mm radius and 2.16 mm swollen radius. Urea content inside material was 40.425 mg urea/g material. The urea diffusivity coefficient for material A, B, and C were 7.27 x 10–6; 15.50 x 10–6 and 0.94 x 10–6 m2 h–1, respectively. Modelling analysis showed the experiment obeyed around only 15% of the Korsmeyer–Peppas model, but there was good correlation (80%) with the unsteady-state diffusion model.
Synthesis of Calix[4]resorcinarene Derivatives as Antimalarial Agents through Heme Polymerization Inhibition Assay Rizky Riyami Putri; Harno Dwi Pranowo; Yehezkiel Steven Kurniawan; Hana Anisa Fatimi; Jumina Jumina
Indonesian Journal of Chemistry Vol 23, No 4 (2023)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.81452

Abstract

Malaria is an endemic disease in tropical countries, including Indonesia, with a high annual mortality rate. Because of that, serious attention shall be given to find new antimalarial agents that are highly active for medical treatment. In this work, we designed and synthesized three calix[4]resorcinarene derivatives and evaluated them as antimalarial agents through in vitro heme polymerization inhibitory assay. The calix[4]resorcinarenes were prepared from resorcinol and corresponding aldehyde derivatives in ethanol media through a cyclo-condensation reaction. The calix[4]resorcinarene products were obtained in 31.1–85.1% yield. The synthesized compounds were subjected to structure elucidation using spectroscopy techniques. The antimalarial activity of calix[4]resorcinarene with aromatic substituent (IC50 = 0.198 mg/mL) was higher than the aliphatic ones (IC50 = 0.282–0.814 mg/mL). It was found that all calix[4]resorcinarenes in this work exhibited stronger antimalarial activity than chloroquine diphosphate as the positive control (IC50 = 1.157 mg/mL). The calix[4]resorcinarenes could interact with hydrogen bonding, thus inhibiting the heme polymerization process. These findings demonstrate that calix[4]resorcinarene derivatives are potential antimalarial agents to be developed for effective medical treatment in the near future.
Titanium Dioxide-Curcumin Composite Materials from Aceh Curcuma Natural Source and Their Evaluation as Antiradical Agents Through In Vitro Study Indriana Kartini; Tutik Dwi Wahyuningsih; Adhi Dwi Hatmanto; Vina Aida Roza; Yehezkiel Steven Kurniawan
Indonesian Journal of Chemistry Vol 23, No 5 (2023)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.80766

Abstract

The usage of antiradical agents is pivotal for suppressing the negative effects of free radicals on human health. Curcumin, a well-known natural antiradical agent, suffers from its low stability and high price, thus, limiting its potential in real applications. In this work, we carried out the impregnation of encapsulated curcumin from Aceh curcuma source on commercial titanium dioxide. The isolation of curcumin was performed using a simple maceration method, while the encapsulation process was done employing carboxymethylcellulose and maltodextrin to give ethanol-curcumin and triacetin-curcumin powders in 30.35% and 37.21% yield, respectively. The composite materials contained curcumin in a range of 0.016–0.374 mg/g. The characterization data revealed that the curcumin was located on the surface of titanium dioxide through hydrogen bonds. The in vitro DPPH assay of the titanium dioxide-curcumin composite material exhibited 39.61 ± 1.36 to 79.70 ± 1.33% antiradical activity which was higher than titanium dioxide (31.78 ± 1.48%). Furthermore, the composite material also gave higher antiradical activity than its curcumin sources, i.e., Aceh curcuma (75.12 ± 1.79%), ethanol-curcumin (56.66 ± 0.25%), and triacetin-curcumin (63.58 ± 0.20%) demonstrating a synergistic antiradical effect of titanium dioxide and curcumin as the antiradical agents. These findings demonstrate the importance of the impregnation and encapsulation of curcumin in composite materials for antiradical applications.
Co-Authors Adhi Dwi Hatmanto Arif Cahyo Imawan Dwi Siswanta Hana Anisa Fatimi Harno Dwi Pranowo Indriana Kartini Jumina Jumina Muhammad Fernadi Lukman Rizky Riyami Putri Triyono Triyono Tutik Dwi Wahyuningsih Vina Aida Roza