Judul: Penapisan Senyawa Bioaktif Daun Jambu Biji (Psidium guajava L.) dan Potensinya secara In Silico sebagai Inhibitor Lipase Pankreas
Abstrak: Obesitas merupakan keadaan abnormal akibat akumulasi lemak dalam jumlah berlebih dan menyebabkan penyakit degeneratif dengan prevalensi yang meningkat di seluruh dunia. Ekstrak etanol daun jambu biji menyebabkan peningkatan metabolisme glukosa dan lipid pada tikus obesitas secara in vivo, namun potensi senyawa bioaktif daun jambu biji yang mampu menginhibisi lipase pankreas secara in silico belum diteliti lebih lanjut. Penelitian bertujuan melakukan penapisan virtual senyawa bioaktif daun jambu biji terhadap reseptor 1LPB. Metode yang digunakan adalah identifikasi senyawa melalui LCMS/MS QToF dilanjutkan penapisan virtual dengan software YASARA Structure. Hasil identifikasi dengan LCMS/MS QToF menunjukkan 21 senyawa dari golongan terpenoid, flavonoid, alkaloid, dan fenolik. Penapisan dilakukan terhadap ligan uji hasil LCMS/MS dan 168 ligan uji hasil studi literatur. Parameter penapisan yaitu nilai ∆Gbind dan Kd yang dibandingkan dengan MUP. Sebanyak 8 senyawa LCMS/MS dan 93 senyawa studi literatur memiliki potensi inhibisi terhadap reseptor 1LPB. Senyawa jacoumaric acid memiliki potensi inhibisi terbaik terhadap reseptor 1LPB Berdasarkan nilai ∆Gbind -9,234 kkal/mol dan Kd 0,1703 μM., Obesity is an abnormal condition due to the accumulation of excessive amounts of fat and it causes degenerative diseases with an increasing prevalence all over the world. The ethanol extract of guava leaves causes an increase in glucose and lipid metabolism of obese mice by in vivo study, but the potential of guava leaf bioactive compounds capable of inhibiting pancreatic lipase in silico has not been studied thoroughly. This study aimed to conduct a virtual screening of guava leaf bioactive compounds against 1LPB receptors. The method applied was compound identification through LCMS/MS QToF followed by virtual screening with YASARA Structure software. The identification results with LCMS/MS QToF showed 21 compounds from terpenoid, flavonoid, alkaloid, and phenolic groups. Virtual screening carried out on experimental ligands from LCMS/MS and 168 from literature studies. The screening parameter were ∆Gbind and Kd value which compared with MUP. A total of 8 LCMS/MS compounds and 93 literature study compounds have inhibitory potential against 1LPB receptors. Jacoumaric acid has the most potential inhibition against 1LPB receptors based on the ∆Gbind value -9.234 kcal/mol and Kd 0.1703 μM.
Keyword: Obesity, pancreatic lipase, guava leaf, in silico, virtual screening

Judul: Uji Potensi Inhibisi Ekstrak Daun Sirih Merah terhadap Lipase Pankreas sebagai Antiobesitas secara In Silico
Abstrak: Obesitas menjadi pemicu munculnya berbagai penyakit degeneratif, seperti stroke, jantung, diabetes tipe 2, dan resistensi insulin. Inhibitor lipase pankreas merupakan agen obat antiobesitas dengan kerja menginhibisi enzim lipase pankreas. Penelitian ini bertujuan melakukan pencarian dan prediksi aktivitas inhibisi terhadap lipase pankreas dari senyawa aktif daun sirih merah. Penelitian dimulai dengan penapisan virtual 60 ligan uji, prediksi stabilitas dan toksisitas ligan, validasi penambatan molekuler, penambatan molekuler, dan visualisasi 2D serta 3D. Hasil menunjukkan bahwa benzethonium octyloxyacetate, hydroxybenzoic acid β-D-glucosyl ester, dan anthocyanins memiliki potensi terbaik dalam menginhibisi enzim lipase pankreas berdasarkan penapisan virtual, stabilitas ligan, toksisitas ligan, energi afinitas, jumlah ikatan hidrogen dengan sisi aktif, jarak ikatan, dan konstanta inhibisi (Ki). Benzethonium octyloxyacetate memiliki nilai afinitas sebesar -8 kkal/mol, memiliki interaksi ikatan hidrogen pada residu His349 sisi aktif reseptor lipase pankreas (6KSM) dengan jarak ikatan 2,94 Å, dan nilai Ki sebesar 1,347 μM., Obesity triggers the emergence of various degenerative diseases, such as stroke, heart disease, type 2 diabetes, and insulin resistance. Pancreatic lipase inhibitors are anti-obesity drug agents that work by inhibiting pancreatic lipase enzymes. This study aims to search and predict the inhibitory activity of pancreatic lipase from the active compound of red betel leaf. The research began with virtual screening of 60 test ligands, prediction of ligand stability and toxicity, validation method of molecular docking, molecular docking, 2D and 3D visualization. The results showed that benzethonium octyloxyacetate, hydroxybenzoic acid β-D-glucosyl ester, and anthocyanins had the best potential in inhibiting pancreatic lipase enzymes based on virtual screening, ligand stability, ligand toxicity, energy affinity, number of hydrogen bonds with active site, bond distance, and constants inhibition (Ki). Benzethonium octyloxyacetate has an affinity value of -8 kcal/mol, has a hydrogen bond interaction on the His349 residue on the active site of the pancreatic lipase receptor (6KSM) with a bond distance of 2,94 Å and Ki value of 1,347 μM.
Keyword: molecular docking, pancreatic lipase, obesity, red betel

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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