Judul: Analisis Potensi Daun Torbangun (Plectranthus amboinicus) sebagai Antibakteri terhadap Klebsiella pneumoniae secara in silico
Abstrak: Resistensi antibiotik adalah masalah global. Bakteri Klebsiella pneumoniae merupakan bakteri prioritas untuk ditemukan antibiotiknya karena adanya enzim extended spectrum beta-lactamase (ESBL) yang menyebabkan bakteri ini mudah mengalami resistensi. Daun torbangun diketahui memiliki banyak sekali kandungan flavonoid yang sering diteliti sebagai antibakteri. Penelitian ini bertujuan menganalisis potensi daun torbangun (Plectranthus amboinicus) sebagai antibakteri terhadap Klebsiella pneumoniae dengan metode in silico. Penelitian dilakukan dengan melakukan penambatan molekuler menggunakan aplikasi AutoDock Vina terhadap enzim dari bakteri Klebsiella pneumonia yaitu SHV (Sulfhydryl variable) dengan senyawa kimia yang diambil dari tanaman daun torbangun. Parameter yang digunakan adalah energi bebas ikatan, konstanta inhibisi, serta visualisasi ligan secara 3D dan 2D. Hasil yang diperoleh menunjukkan ligan alami memiliki energi bebas ikatan sebesar -6,7 kcal/mol dan konstanta inhibisi 12,11 µM. Nilai energi bebas ikatan dan konstanta inhibisi dari luteolin 3’Oglucuronide, apigenin 7-glucuronide, dan asam rosmarinat menunjukkan hasil yang lebih baik dibandingkan dengan ligan alami dari SHV-1 (1,4-thiazepine)., Antibiotic-resistant is a global issue. Klebsiella pneumoniae has high priority to find its antibiotic because it has extended-spectrum beta-lactamase (ESBL) enzyme that makes the bacteria easy to resist the antibiotic. Indian borage is one of the empirical medicinal plants that contain flavonoids being used for treating the disease. This research had the purpose of analyzing Indian borage potential as an antibacterial for Klebsiella pneumoniae in silico. Docking is the method for this research by using AutoDock Vina, an application to attach enzyme ESBL from Klebsiella pneumoniae which mention as SHV (Sulfhydryl variable) and metabolite seconders from the plant. The analyzed parameter was binding free energy, inhibition constant, and visualization in 3D and 2D. Binding free energy and inhibition constant of a native ligand is -6.7 kcal/mol and 12.11 µM. Binding free energy value of apigenin 7-glucuronide and rosmarinic acid perform higher potency than the native ligand of SHV-1 (1,4-thiazepine).
Keyword: Daun torbangun, Klebsiella pneumoniae, Resistensi antibiotik, Penambatan molekuler

Judul: Potensi Senyawa Aktif Sungkai (Peroema canescens) dalam Menginhibisi Enzim Beta-Laktamase Secara In Silico.
Abstrak: Kasus resistensi bakteri terhadap antibiotik menjadi ancaman serius bagi kesehatan manusia karena menurunkan efektivitas obat untuk mencegah dan menyembuhkan infeksi bakteri. Resistensi dapat disebabkan oleh pengobatan yang tidak tuntas. Salah satunya yaitu bakteri Escherichia coli yang menghasilkan enzim CTX-M yang merupakan jenis dari beta-laktamase yang menghambat kerja antibiotik golongan beta-laktam. Sungkai merupakan salah satu tanaman obat tradisional dan terbukti menghambat pertumbuhan bakteri Escherichia coli. Penelitian ini bertujuan mengidentifikasi senyawa aktif sungkai yang berpotensi menginhibisi beta-laktamase serta analisis interaksi yang terjadi secara in silico. Senyawa aktif daun sungkai ditambatkan ke reseptor beta-laktamase, kemudian dianalisis interaksinya serta diprediksi bioavailabilitas dan toksisitas. Hasil penelitian menunjukan sebanyak 6 dari 19 ligan uji lolos penapisan hingga akhir dan berpotensi menjadi inhibitor beta-laktamase. Senyawa tersebut antara lain, beta-sitosterol, 3,4’,5-thrihydroxy-3,’,7-dimenthoxyflavanone, physcion, isorhamnetin, chrysoeriol, quercetin 3,3 dimetly ether, dan vintexin-2-O rhamnoside., Cases of bacterial resistance to antibiotic has become a serious threat for human health because they reduce the effectiveness of drugs in preventing and treating bacterial infections. Resistance can be caused by uncomplete treatment. One of example is Escherichia coli bacteria which produces the CTX-M enzyme, that is a type of of beta-lactamase that inhibits the action of beta-lactam antibiotics. Sungkai is one of the traditional medicinal PLANTS and it is proved inhibiting the growth of Escherichia coli. This research aims to identify the active compounds of sungkai that have the potential to inhibits beta-lactamase and analyze interactions of molecular docking. The active compounds of sungkai leaves are docked to the beta-lactamase receptor, then their interactions are analyzed, predicting bioavailability, and toxicity. The results showed that 6 of the 19 tested ligands pass the screening and have the potential to become beta-lactamase inhibitors. The compounds are beta-sitosterol, 3,4’,5-thrihydroxy-3’7-dimenthoxyflavanone, physcion, isorhmaetin, chrysoeriol, quercetin 3,3 dimetly ether, and vintexin-2-O-rhamnoside.
Keyword: resistent, beta-lactamase inhibitors, sungkai

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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