Judul: In Silico Analysis of Flavonoid Compounds of Bay Leaf (Syzygium polyanthum) in inhibiting 3C-Like Protease SARS-CoV-2
Abstrak: Daun salam (Syzygium polyanthum) diidentifikasi memiliki senyawa aktif flavonoid. Flavonoid dilaporkan memiliki aktivitas antivirus. SARS-CoV-2 merupakan virus dari penyakit COVID-19. Virus ini dapat ditularkan dari manusia ke manusia. SARS-CoV-2 memiliki beberapa komponen penting salah satunya yaitu 3C-Like Protease. 3C-Like Protease berperan penting terhadap replikasi coronavirus. Penelitian ini bertujuan mempelajari interaksi antara senyawa flavonoid Daun salam (Syzygium polyanthum) dalam menghambat 3C-like Protease SARS-CoV-2 melalui uji in silico menggunakan teknik penapisan virtual serta memprediksi kemampuannya untuk dijadikan sediaan obat oral dengan memprediksi sifat bioavailabilitas dan toksisitasnya. Potensi terbaik terlihat pada Quercitrin dan Myricitrin dengan masing-masing ΔG -8.926 kkal/mol dan -8.858 kkal/mol. Dua senyawa tersebut memiliki berbagai interaksi ikatan hidrogen dan hidrofobik terhadap asam amino pada reseptor, serta diprediksi memiliki bioavailabilitas yang cukup baik dan tidak bersifat toksik, sehingga dapat menjadi kandidat inhibitor potensial enzim 3C-like Protease SARS-CoV-2 untuk dijadikan sediaan obat oral dalam menangani pandemik COVID-19., Bay leaf (Syzygium polyanthum) has been identified to have active flavonoid compounds. Flavonoids are reported to have antiviral activity. SARSCoV-2 is a virus from the COVID-19 disease. This virus can be transmitted from human to human. SARS-CoV-2 has several important components, one of which is 3C-Like Protease. 3C-Like Protease plays an important role in coronavirus replication. This research aims to study the interaction of flavonoid compounds in bay leaf (Syzygium polyanthum) in inhibiting the 3C-like Protease SARS-CoV-2 through in silico analysis using virtual screening techniques and predicting its ability to be used as an oral drug candidate by predicting its bioavailability and toxicity. The best potency was found in Quercitrin and Myricitrin with ΔG value of -8,926 kcal/mol and -8,858 kcal/mol, respectively. The two compounds have various hydrogen bondings and hydrophobic interactions with the amino acid residues of the receptor and are predicted to have good bioavailability and non-toxic properties so that they become potential inhibitors of 3C-Like Protease of SARSCoV-2 as oral drug candidate in dealing with the COVID-19 pandemic
Keyword: bay leaf, 3C-Like Protease, flavonoid, SARS-CoV-2

Judul: Analisis Potensi Senyawa Flavonoid pada Daun Salam sebagai Inhibitor Papain-Like Protease SARS-CoV-2 secara In Silico
Abstrak: SARS-CoV-2 menyandi enzim papain-like protease (PLpro) yang berperan dalam proses replikasi virus. Hal tersebut menjadikan enzim PLpro sebagai target penting dalam pengembangan obat antivirus yang baru. Daun salam (Syzygium polyanthum) merupakan salah satu tanaman obat di Indonesia yang berasal dari famili Myrtaceae. Tanaman ini dilaporkan memiliki kandungan flavonoid yang potensial sebagai anti-SARS-CoV-2. Penelitian ini bertujuan mengidentifikasi senyawa flavonoid daun salam sebagai kandidat inhibitor enzim PLpro SARS-CoV-2 melalui uji in silico, serta menganalisis interaksi molekuler senyawa flavonoid tersebut dengan sisi aktif enzim PLpro. Metode yang digunakan dalam penelitian ini adalah penapisan virtual menggunakan perangkat lunak YASARA Structure. Hasil penelitian menunjukkan 9 dari 11 senyawa uji memiliki aktivitas penghambatan terhadap enzim PLpro, antara lain kuersitrin, mirisitrin, mirisetin, kuersetin, epigalokatekin-3-galat, delfinidin, malvidin, kuersetagetin, dan flavan-3-ol. Senyawa kuersitrin berpotensi sebagai inhibitor terbaik PLpro dengan energi ikatan sebesar -7.3450 kkal/mol dan konstanta disosiasi sebesar 4.13 x 106 pM, sehingga senyawa ini dapat dikembangkan sebagai obat anti SARS-CoV-2., SARS-CoV-2 encodes papain-like protease (PLpro) that plays an essential role in viral replication, making it an important target for developing new antiviral drugs. Bay leaf (Syzygium polyanthum) is one of the medicinal plants in Indonesia that comes from the Myrtaceae family. This plant is reported to contain flavonoids that are potential as antivirus SARS-CoV-2. This study aims to identify the flavonoid compounds of the bay leaf as a candidate for SARS-CoV-2 PLpro enzyme inhibitor through an in silico test, as well as to analyze the molecular interaction of flavonoid compounds with the active site of the PLpro enzyme. Virtual screening doing by the YASARA Structure software. As a result, 9 of the 11 analyze compounds have the potential to inhibit the activity of the PLpro enzyme, such as quercitrin, myricitrin myricetin, quercetin, epigallocatechin-3-gallate, delphinidin, malvidin, quercetagetin, and flavan-3-ol. Quercitrin is the best compound that inhibits PLpro with a binding energy of -7.3450 kcal/mol and a dissociation constant of 4.13 x 106 pM, so it can be used as an anti-SARS-CoV-2 drug development agent.
Keyword: bay leaf, flavonoid, PLpro, SARS-CoV-2, virtual screening

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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