Judul: In Silico Analysis of Derivative Compounds Anthocyanins, Ellagic Acid, and Catechins as Aldose Reductase Inhibitors
Abstrak: Salah satu komplikasi diabetes melitus yang menyerang mata yaitu katarak diabetik yang disebabkan oleh tingginya aktivitas enzim aldosa reduktase pada jalur poliol dalam kondisi hiperglikemik. Senyawa aktif buah beri berpotensi sebagai inhibitor aldosa reduktase tetapi senyawa turunan antosianin, asam elagat, dan katekin pada buah beri belum diketahui. Penelitian ini bertujuan menguji potensi setiap senyawa turunan antosianin, asam elagat, dan katekin dari buah strawberry, blueberry, dan blackberry sebagai inhibitor enzim aldosa reduktase secara in silico. Penambatan molekuler 41 ligan uji dilakukan melalui software PLANTS. Hasil penelitian menunjukkan reseptor aldosa reduktase tervalidasi dengan kode pdb 1US0 diunduh dari Research Collaboratory for Structural Bioinformatics (RCSB) memiliki nilai RMSD 0.7611 Å. Hasil penambatan molekuler 41 ligan uji diperoleh 11 ligan uji berdasarkan parameter score docking dan jenis interaksi ligan-reseptor, dari 11 ligan diperoleh 5 ligan berdasarkan uji bioavailabilitas, serta diperoleh 3 ligan berdasarkan uji toksisitas. Senyawa turunan katekin yaitu epikatekin, epigalokatekin, dan galokatekin merupakan 3 ligan uji terbaik sebagai inhibitor aldosa reduktase., One of the complications of diabetes mellitus that affect the eyes is diabetic cataracts, caused by high activity of aldose reductase enzyme in the polyol pathway under conditions of hyperglycemia. Active compounds in berries had the potential to inhibit aldose reductase, but the compounds derived from anthocyanins, ellagic acid, and catechins in berries are not yet known. This study aimed to test the potential of each derived compound from anthocyanins, ellagic acid, and catechins from strawberries, blueberries, and blackberries as aldose reductase enzyme inhibitors in silico. Molecular docking of 41 test ligands were conducted using the PLANTS software. The results showed that the aldose reductase receptor validated with pdb code 1US0 downloaded from the Research Collaboratory for Structural Bioinformatics (RCSB) had an RMSD value of 0.7611 Å. The results of molecular docking of the 41 test ligands obtained 11 ligands based on docking score parameters and the type of ligand-receptor interaction. Out of the 11 ligands, 5 ligands were obtained based on bioavailability testing, and 3 ligands were obtained based on toxicity testing. The catechin derivatives, namely epicatechin, epigallocatechin, and gallocatechin, were the top 3 test ligands as aldose reductase inhibitors.
Keyword: aldosa reduktase, inhibitor, senyawa turunan, penambatan molekuler

Judul: Potensi inhibisi senyawa aktif buah stroberi terhadap aktivitas enzim aldosa reduktase dengan simulasi penambatan molekuler.
Abstrak: Katarak diabetik adalah masalah utama dari penyakit komplikasi diabetes yang disebabkan oleh tingginya aktivitas enzim aldosa reduktase pada jalur poliol dalam kondisi hiperglikemik. Inhibitor aldosa reduktase telah banyak ditemukan, akan tetapi belum lulus uji klinis. Buah stroberi (Fragaria x ananassa) merupakan salah satu sumber nutrisi yang memiliki sifat hipoglikemik. Penelitian ini bertujuan mempelajari interaksi molekuler dengan teknik simulasi penambatan molekuler serta menguji potensi setiap senyawa aktif dari buah stroberi sebagai inhibitor aldose reduktase secara in silico melalui analisis energi ikat (ΔG), konstanta inhibisi (Ki), jenis interaksi, dan keserupaan situs ikat (binding site). Katekin, p-kumaril heksosa-4-O-heksosida, p-kumaril heksosa merupakan ligan yang paling mirip dengan epalrestat dan berpotensi sebagai inhibitor non kompetitif. Sementara asam askorbat dan elagik berpotensi sebagai inhibitor kompetitif.
Keyword: Aldosa reduktase, inhibitor, penambatan molekule, stroberi

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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