Judul: Studi In silico Senyawa Alami Kulit Kayu Gmelina arborea terhadap RNA-dependent RNA polymerase SARS-CoV-2
Abstrak: SARS-CoV-2 menyebabkan sindrom pernafasan akut dan telah menginfeksi banyak korban dari berbagai negara. SARS-CoV-2 menggunakan RNA-dependent RNA polymerase untuk melakukan replikasi dan transkripsi genom virus. Tanaman gmelina dapat dimanfaatkan sebagai obat tradisional. Penelitian bertujuan menganalisis interaksi senyawa alami kulit kayu gmelina (Gmelina arborea Roxb) dalam menghambat enzim RNA-dependent RNA polymerase SARS-CoV-2 melalui penambatan molekuler serta menganalisis sifat farmakokinetik dan toksisitas senyawa. Gmelinol (∆G -6.192 kkal/mol) lebih unggul dibanding ligan uji lainnya berdasarkan nilai energi bebas ikatan, interaksi dengan residu aktif, dan analisis Lipinski. Hasil prediksi ADME menyatakan bahwa gmelinol berperan sebagai substrat dan inhibitor CYP3A4. Hasil prediksi toksisitas oral menyatakan bahwa gmelinol termasuk senyawa kelas IV yang berarti berbahaya jika tertelan., SARS-CoV-2 causes acute respiratory syndrome and has infected many people in various countries. SARS-CoV-2 uses an RNA-dependent RNA polymerase enzyme for replication and transcription of the viral genome. Gmelina plants can be used as traditional medicine. This study aimed to analyze the interaction of natural compounds in the gmelina bark (Gmelina arborea Roxb) in inhibiting the enzyme of SARS-CoV-2 RNA-dependent RNA polymerase by molecular docking, analyze the pharmacokinetic properties, and toxicity. Gmelinol (∆G -6.192 kcal/mol) was better than other ligands based on binding free energy, interactions with active residues, and Lipinski analysis. ADME prediction stated that gmelinol acts as a substrate and inhibitor of CYP3A4. Oral toxicity prediction stated that gmelinol is a class IV compound which harmful if swallowed.
Keyword: gmelina, gmelinol, molecular docking, RNA-dependent RNA polymerase, SARS-CoV-2

Judul: Analisis Penambatan Molekuler Senyawa Aktif Kulit Kayu Gmelina arborea terhadap Endoribonuklease SARS-CoV-2
Abstrak: COVID-19 disebabkan oleh infeksi SARS-CoV-2, tingkat keparahannya beragam sesuai dengan tingkat kekebalan tubuh penderita. Aktivitas antioksidan dalam kulit kayu Gmelina berpotensi menurunkan aktivitas protein fungsional SARS-CoV-2. Penelitian ini bertujuan memperoleh informasi mencakup (1) situs pengikatan ligan-protein; (2) nilai ΔG dan konstanta disosiasi; (3) ikatan hidrogen dan interaksi hidrofobik antar molekul; (4) karakteristik kimia senyawa aktif kulit kayu Gmelina. Penelitian ini menggunakan metode in silico melalui penambatan molekuler secara komputasi dengan aplikasi YASARA structure. Berdasarkan hasil penelitian, senyawa balanophonin memiliki pengikatan yang paling baik dibandingkan senyawa aktif kulit kayu Gmelina lainnya dengan nilai ΔG -7,1270 kkal/mol serta konstanta disosiasi 5,96 μM. Dengan demikian, simpulan penelitian ini senyawa aktif balanophonin dengan pengikatan terbaik memiliki nilai ΔG lebih besar dari uridin-5’-monofosfat dan tipiracil, yang merupakan ligan alami dan pembandingnya. Ikatan hidrogen serta interaksi hidrofobik antar molekul memfasilitasi penambatan dan inhibisi aktivitas endoribonuklease SARS-CoV-2., COVID-19 is caused by infection of SARS-CoV-2, the severity based on patient's immune system. Antioxidant activity in Gmelina bark potentiates to decrease activities of SARS-CoV-2 functional protein. This study aims to obtain information including (1) ligand-protein binding sites; (2) the value of G and the dissociation constant; (3) intermolecular hydrogen bonds and hydrophobic interactions; (4) Chemical properties of active compound in Gmelina bark. This research uses in silico method through computational molecular docking with the YASARA structure application. Based on the results, balanophonin has the best binding affinity to other active compounds of Gmelina bark with the value of ΔG -7,1270 kcal/mol and dissociation constant of 5.96 μM. Thus, this study concludes balanophonin with the best binding has a ΔG value which larger than uridine-5'-monophosphate and tipiracil as their natural and comparison ligand. Intermolecular hydrogen bonds and hydrophobic interactions facilitate the binding and inhibition of SARS-CoV-2 endoribonuclease activity.
Keyword: Molecular Docking, Gmelina arborea, Endoribonuclease, SARS-CoV-2

Judul: Asymptotic Distribution of Estimator for the Intensity Function of a Doubly Periodic Poisson Process
Abstrak: In this manuscript, estimation of the intensity function of a doubly periodic Poisson process is discussed. It is assumed that only a single realization of the Poisson process is observed in a bounded window [0,n]. It is also assumed that the period of the intensity function is known. The rate of consistency and asymptotic normality of the estimator are formulated. Finally, a confidence interval for the local intensity function is also formulated.
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