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: Analisis in silico senyawa bioaktif buah blueberry, blackberry, dan raspberry sebagai inhibitor enzim aldosa reduktase
Abstrak: Katarak diabetik merupakan salah satu penyebab utama penyakit komplikasi diabetes yang disebabkan oleh tingginya aktivitas enzim aldosa reduktase pada jalur poliol. Potensi penghambatan enzim aldosa reduktase oleh senyawa aktif blueberry, blackberry, dan raspberry dapat dilakukan secara in silico dengan teknik penambatan molekuler. Teknik penambatan molekuler dilakukan untuk melihat interaksi molekuler senyawa atau ligan dengan reseptor atau enzim. Penelitian ini bertujuan untuk mengetahui potensi masing-masing senyawa bioaktif dari buah blueberry, blackberry, dan raspberry sebagai alternatif inhibitor aldosa reduktase melalui parameter energi ikat (ΔG), konstanta inhibisi (Ki), jenis interaksi dan binding site similarity (BSS). Potensi inhibisi terbaik dimiliki chrysin (ΔG -10.9 kkal/mol dengan Ki 0.010 μM) dan apigenin (ΔG -10.5 kkal/mol dengan Ki 0.020 μM), selain itu persentase BSS tertinggi terhadap epalrestat dimiliki chrysin dan apigenin yaitu sebesar 82.5% dan 70.58%. Tidak adanya gugus karboksilat pada chrysin dan apigenin menyebabkan chrysin dan apigenin mengikuti mekanisme inhibisi kompetitif. Berdasarkan parameter-paramater tersebut, buah raspberry memiliki potensi terbaik sebagai inhibitor aldosa reduktase alternatif dari epalrestat.
Keyword: Aldosa reduktase, inhibitor, penambatan molekuler, senyawa bioaktif

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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