Judul: Kajian Metabolomik Rimpang Kunyit Menggunakan Kromatografi Cair-Spektroskopi Massa
Abstrak: Pendekatan metabolomik dengan instrumen kromatografi cair-spektroskopi massa (LC-MS) dilakukan untuk mengetahui profil metabolit kunyit (Curcuma longa) berdasarkan perbedaan daerah sumber. Pada penelitian ini, sampel kunyit yang digunakan berasal dari 5 daerah yang berbeda, yaitu Karanganyar, Nagrak, Ngawi, Bogor, dan Sukabumi. Kromatogram LC-MS diolah menggunakan perangkat lunak MZmine dan The Unscrambler. MZmine mengolah kromatogram LC-MS menjadi bentuk mass array. Identifikasi pendugaan metabolit dilakukan dengan membandingkan massa akurat puncak terukur hasil mass array dengan massa akurat pasti senyawa metabolit turunan kurkuma yang terdapat pada dictionary natural product (dnp.chemnetbase.com), serta melalui studi pustaka jalur biosintesis genus kurkuma (peta metabolit). Analisis komponen utama (PCA) dengan perangkat lunak The Unscrambler mengelompokkan sampel kunyit berdasarkan perbedaan daerah sumber serta menentukan metabolit penciri. Sifat bioaktivitas yang diuji ialah aktivitas antioksidan kunyit. Hasil identifikasi menunjukkan total 121 metabolit di dalam genus kurkuma teridentifikasi dan ada perbedaan komposisi kandungan metabolit berdasarkan daerah sumber sampel. Pola pengelompokan hasil PCA menunjukkan pengelompokan berdasarkan ulangan sampel untuk kunyit Sukabumi dan Karanganyar sedangkan tidak mengelompok untuk sampel kunyit daerah sumber lain. Aktivitas antioksidan paling tinggi ditunjukkan oleh kunyit Sukabumi dengan nilai IC50 47.63 μg/mL. Sampel kunyit Sukabumi dapat dicirikan dengan tidak adanya kandungan kalebin A yang memiliki nilai m/z 384,939.
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Judul: Penentuan Kadar Kurkuminoid dalam Kunyit dengan Spektrofotometri Derivatif
Abstrak: Indonesia as one of agricultural countries has various kinds of plant than can be used for pharmaceutical product, including turmeric that contains curcuminoid compound. Curcuminoid has efficacy as an antihepatoxic, anticholesterol, tumor and cancer inhibiting compound. In recent years, research has been developing a simple, fast, and low-cost analysis method from spectroscopy and chemometric combination, i.e. ; derivative spectrophotometry. In this research, turmeric extraction was conducted using sonication method, and its curcuminoid content was determined using spectrophotometry method. Analysis with UV-vis spectrophotometry and high performance liquid chromatography (HPLC) were also conducted as reference methods. Curcuminoid in turmeric using derivative spectrophotometry was 14.33 mg/g whereas with UV-vis spectrophotometry and HPLC were 14.18 and 45.40 mg/g, respectively. Based on statistical analysis for these results, derivative spectrophotometry can be applied for analyzing curcuminoid content with good accuracy and precision. This developed method was cheaper, faster, and easier than the conventional method. In addition, matrices influence in samples can be reduced compared with that using conventional spectrophotometry.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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