Judul: Analysis Potency of Red Betel Active Compund as an Inhibitor of Acetylcholinesterase Enzyme Through In Silico
Abstrak: Alzheimer merupakan penyakit yang menyebabkan terjadinya penurunan fungsi kognitif dan merupakan penyebab kematian ketujuh terbesar di dunia. Inhibitor enzim asetilkolinesterase (AChE) merupakan pengobatan alzheimer yang paling banyak berkembang hingga saat ini, namun pengonsumsiannya masih memberikan banyak efek samping. Sirih merah, tanaman yang telah banyak digunakan dalam pengobatan herbal mengandung banyak senyawa aktif yang diharapkan dapat berpotensi sebagai inhibitor AChE. Penelitian ini bertujuan menemukan senyawa aktif sirih merah yang berpotensi dalam menginhibisi enzim AChE secara in silico menggunakan teknik penambatan molekuler. Potensi inhibisi terbaik dimiliki oleh copaene, auron, dan 1,1’-(6,6’-Dihydroxy-5,5’-dimethoxy3,3’-biphenyldiyl)di(1-propanone) dengan nilai ΔG dan Ki berturut-turut sebesar - 7,738; -7,658; dan -5,348 kkal/mol serta Ki 2,045; 2,498; dan 118,9 µM. Ketiga ligan tersebut juga berinteraksi dengan sisi aktif CAS (Catalytic Active Site) atau PAS (Peripheral Aromatic Site) yang berperan penting dalam penghambatan enzim AChE untuk terapi antialzheimer., Alzheimer is a disease that causes the decline of cognitive function and considered as the seventh biggest cause of death in the world. Acetylcholinesterase (AChE) enzyme inhibitors are the most established treatment for alzheimer until now despite its possible side effects. Red betel, a widely used plant in herbal medication, contains many active compounds which are expected to be potential for AChE inhibitors. The study aims to research the active compound of red betel that has the potential to inhibit the AChE enzyme in silico through molecular docking techniques. The finest inhibitory potentials were possessed by copaene, aurone, and 1,1’-(6,6’ -Dihydroxy- 5,5’ -dimethoxy- 3,3’ -biphenyldiyl)di(1- propanone) indicated correspondingly by the value of ΔG and Ki values -7.738; - 7,658; and -5.348 kcal/mol and Ki 2,045; 2,498; and 118,9 µM. Those three ligands also interacted with the active site CAS (Catalytic Active Site) or PAS (Peripheral Aromatic Site) that plays a fundamental role to inhibit the AChE enzyme for antialzheimer therapy.
Keyword: acetylcholinesterase, alzheimer, molecular docking, red betel

Judul: Molecular Docking of Black Cumin Active Compound to Inhibits Cholinesterase Enzyme in the Development of Alzheimer’s Therapy
Abstrak: Asetilkolinesterase (AChE) dan Butirilkolinesterase (BChE) merupakan dua jenis enzim kolinesterase yang berperan dalam penurunan kadar asetilkolin sebagai gejala khas penyakit alzheimer. Jintan hitam memiliki beragam senyawa aktif yang berpotensi menghambat aktivitas kedua enzim. Penelitian ini bertujuan menganalisis interaksi beberapa senyawa aktif penting dari jintan hitam dalam menghambat aktivitas kedua enzim. Senyawa uji terbaik dipilih berdasar analisis sifat kemiripan obat yang memenuhi kriteria dalam bioavailabilitas, toksisitas dan aspek farmakokinetik sebagai obat. Analisis penambatan molekul dilakukan dengan perangkat lunak komputer PyRx Virtual Screening dan YASARA Structure. Hasil penelitian menunjukkan 7 dari 25 senyawa uji diduga memiliki aktivitas penghambatan pada enzim AChE dan BChE. Senyawa nigelicin berpotensi sebagai inhibitor terbaik AChE (ΔG -7,74 kcal/mol; %BSS 69,23%). Senyawa nigelidin berpotensi sebagai inhibitor terbaik BChE (ΔG -6,73 kcal/mol; %BSS 33,33%). Ikatan inhibitor dan enzim pada keduanya didominasi interaksi hidrofobik dengan cincin aromatik berjajar. Kedua senyawa tergolong kelompok alkaloid jintan hitam yang berpotensi dikembangkan sebagai herbal terapi alzheimer., Acetylcholinesterase (AChE) and Butyrylcholinesterase (BChE) are two types of cholinesterase enzyme that plays important role in reducing acetylcholine as a symptom of alzheimer. Black cumin has a variety of active compounds and the potential to inhibit the activity of both enzymes. This study aims to analyze interaction of some crucial active compounds of black cumin in inhibiting AChE and BChE enzymes. Active compounds selected through drugs-likeness analysis that in compliance with bioavailability, toxicity and pharmacocinetics aspect. Docking simulation doing by the Pyrx Virtual Screening software and the YASARA Structure software. As a result, 7 of the 25 analyze compounds have the potential to inhibit activity of both enzymes. Nigelicin is the best compound that inhibits AChE (ΔG -7,74 kcal/mol; %BSS 69,23%). Nigelidin is the best compound that inhibits BChE (ΔG -6.73 kcal/mol; %BSS 33,33%). Both inhibitor and enzyme complex dominated by hydrophobic with lined aromatic structure. Both compounds are classified as alkaloid of black cumin that potential as alzheimer’s therapy.
Keyword: alzheimer’s disease, acetylcholinesterase, butyrylcholinesterase, black cumin, molecular docking

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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