Husein H. Bahti

Antiplasmodial and other constituents from four Indonesian Garcinia spp.

Phytochemical investigations of four Garcinia spp. from Indonesia, i.e. Garcinia griffithii T. Anderson, Garcinia celebica L., Garcinia cornea L. and Garcinia cymosa K. Schum (Clusiaceae), have resulted in the isolation of a xanthone, 1,5-dihydroxy-3,6-dimethoxy-2,7-diprenylxanthone, 1,7-dihydroxyxanthone, isoxanthochymol, beta-sitosterol-3-O-beta-D-glucoside and stigmasterol-3-O-beta-D-glucoside from the stem bark of G. griffithii; friedelin and 3beta-hydroxy-23-oxo-9,16-lanostadien-26-oic acid or garcihombronane D from leaves of G. celebica; 23-hydroxy-3-oxo-cycloart-24-en-26-oic acid and epicatechin from stem bark of G. cornea; (+/-)-morelloflavone, morelloflavone-7-O-beta-D-glucoside or fukugiside, the triterpene 3beta-hydroxy-5-glutinen-28-oic acid and canophyllol from stem bark of G. cymosa. The xanthone and garcihombronane D displayed a selective activity against Plasmodium falciparum; isoxanthochymol and the triterpene beta-hydroxy-5-glutinen-28-oic acid a broad but non-selective antiprotozoal activity.

Fast and simultaneously determination of light and heavy rare earth elements in monazite using combination of ultraviolet-visible spectrophotometry and multivariate analysis

Rare Earth Elements (REE) are elements that a lot of function for life, such as metallurgy, optical devices, and manufacture of electronic devices. Sources of REE is present in the mineral, in which each element has similar properties. Currently, to determining the content of REE is used instruments such as ICP-OES, ICP-MS, XRF, and HPLC. But in each instruments, there are still have some weaknesses. Therefore we need an alternative analytical method for the determination of rare earth metal content, one of them is by a combination of UV-Visible spectrophotometry and multivariate analysis, including Principal Component Analysis (PCA), Principal Component Regression (PCR), and Partial Least Square Regression (PLS). The purpose of this experiment is to determine the content of light and medium rare earth elements in the mineral monazite without chemical separation by using a combination of multivariate analysis and UV-Visible spectrophotometric methods. Training set created 22 variations of concentration an...

Synthesis of gadolinium doped titanium(IV) oxide and their photocatalytic activity to decrease chemical oxygen demand (COD) value of water pollutants

Pesticides are widely used for the control of plant disease. Unfortunately they are highly toxic to terraneous and aquatic life; this is a particular problem in agricultural areas. TiO2 is widely used for pesticide control because of its photocatalytic activity, but it still has inadequacy in its wide band gap. Alternatively, the wide band gap of TiO2 could be narrowed by modification with rare earth element such as gadolinium, so the photocatalytic activity of TiO2could be significantly enhanced. The purpose of this experiment is to synthesize Gd/TiO2 and its application to reduce COD of water pollutants such as carbosulfan pesticide. This experiment is done by doping gadolinium oxide into titanium tetra isopropoxide by sol-gel method. The crystal structure is characterized by using XRD, shown anatase successfully obtained with the smallest crystallite size is 37.655 nm, indicated optimum calcination time is 4 hours. SEM-EDX result shown morphology of crystal is big aggregates. Photocatalytic activity is tested to carbosulfan pesticide, obtained the COD percent decreases up to 87.88%.Pesticides are widely used for the control of plant disease. Unfortunately they are highly toxic to terraneous and aquatic life; this is a particular problem in agricultural areas. TiO2 is widely used for pesticide control because of its photocatalytic activity, but it still has inadequacy in its wide band gap. Alternatively, the wide band gap of TiO2 could be narrowed by modification with rare earth element such as gadolinium, so the photocatalytic activity of TiO2could be significantly enhanced. The purpose of this experiment is to synthesize Gd/TiO2 and its application to reduce COD of water pollutants such as carbosulfan pesticide. This experiment is done by doping gadolinium oxide into titanium tetra isopropoxide by sol-gel method. The crystal structure is characterized by using XRD, shown anatase successfully obtained with the smallest crystallite size is 37.655 nm, indicated optimum calcination time is 4 hours. SEM-EDX result shown morphology of crystal is big aggregates. Photocatalytic activity is...

PEMBUATAN RESIN PENUKAR KATION SELULOSA FOSFONAT DAN EFISIENSI PERTUKARANNYA TERHADAP UNSUR TANAH JARANG

Kromatografi pertukaran ion telah digunakan secara luas dalam proses pemisahan dan pemurnian. Resin penukar ion komersial sebagai fasa diam pada umumnya berbasis polistiren. Pada penelitian ini dikaji pembuatan resin penukar kation dengan gugus sulfonat yang diikatkan pada selulosa dari serat batang pisang sebagai limbah pertanian. Pembuatan resin penukar kation diawali dengan proses isolasi selulosa dari serat batang pisang, kemudian proses fosforilasi menggunakan fosfor oksiklorida 16,67% dalam metilen klorida (1:5), dan karakterisasi resin selulosa fosfonat menggunakan spektrofotometer inframerah, XRF, uji kapasitas pertukaran ion dan efisiensinya terhadap ion-ion Gadolinium (III), Neodimium (III), Serium (IV), Samarium (III), Praseodimium (III) dan Yttrium (III). Hasil penelitian menunjukkan kemurnian selulosa dari proses isolasi adalah 90,70% dan proses fosforilasi optimum pada suhu 90 o C selama 2,5 jam. Karakterisasi dari spektrum inframerah menunjukkan adanya puncak baru, yaitu pada serapan 1240 cm -1 yang merupakan daerah untuk regangan P-O-C dan diperkuat dengan meningkatnya intensitas pada serapan 1319 cm -1 yang menunjukkan regangan P=O. Massa jenis resin selulosa terfosforilasi adalah 1,68 g/mL dan kapasitas pertukaran kation 1,99 mek/g. Efisiensi pertukaran kation resin terhadap ion-ion Gadolinium (III), Neodimium (III), Serium (IV), Samarium (III), Praseodimium (III) dan Yttrium (III) berturut-turut adalah 108,8±0,17x10 -3 , 111,9±0,04x10 -3 , 98,1±0,02 x10 -3 , 96,4±0,79x10 -3 , 82,3±0,04x10 -3 dan 92,4±0,04x10 -3 mek/g. Kata Kunci: Resin penukar kation, selulosa, fosforilasi, kapasitas pertukaran ion, efisiensi pertukaran ion

Synthesis and characterization of dihexyldithiocarbamate as a chelating agent in extraction of gold(III)

The use of dialkyldithiocarbamates as chelating agents of transition metals have been developing for decades. Many chelating agents have been synthesized and used in the extraction of the metals. Studies on particular aspects of extraction of the metals, such as the effect of increasing hydrophobicity of chelating agents on the effectiveness of the extraction, have been done. However, despite the many studies on the synthesis and applications of this type of chelating agents, interests in the aspect of molecular structure of the synthesized ligands and of their complexes, have been limited. This study aimed at synthesizing and characterizing dihexylthiocarbamate, and using the ligand for the extraction of gold III). Characterization of the ligand and of its metal complex were done by using elemental analysis, DTG, and spectroscopic methods to include NMR, (1H, and 13C), FTIR, and MS-ESI. Data on the synthesis, characterization, and the application of the ligand as a chelating agent are presented.

Tetraoksigenasi Santon dari Kulit Batang Garcinia nigrolineata Tetraoxygenated Xanthone from The Stem Bark of Garcinia nigrolineata

A tetraoxygenated xanthone, 1,7-dihidroxy-3-methoxy-4-(3methylbut-2-enyl),6’,6’ –dimethylpyrano (2’ , 3’ : 5, 6) xanthone had been isolated from the ethyl acetate extract of the stem bark of Garcinia nigrolineata Planch Ex T. Anders. The structure of these compounds were determined on the basis of spectroscopic NMR 1D and 2D.