Judul: Penambatan Molekuler dan Studi In Vitro Senyawa Bioaktif Ekstrak dan Fraksi Daun Sirih Merah (Piper crocatum) sebagai Inhibitor -Glukosidase.
Abstrak: Tren peningkatan DM tipe 2 ini telah menjadi masalah medis serius di seluruh dunia yang mendorong setiap upaya dalam mengeksplorasi agen terapi baru. DM tipe 2, penghambatan terapi α-glukosidase bermanfaat untuk menunda penyerapan glukosa setelah makan. Enzim α-glukosidase adalah enzim yang berperan dalam pemecahan karbohidrat menjadi glukosa dan dapat meningkatkan kadar glukosa darah, sehingga untuk mencegah naiknya gula darah maka dibutuhkan suatu inhibitor enzim α-glukosidase. Daun sirih merah digunakan secara turun menurun oleh masyarakat Indonesia dan dipercaya dapat menurunkan kadar glukosa darah. Penelitian sebelumnya berhasil mengisolasi senyawa bioaktif yang terkandung di dalam daun sirih merah, mengandung delapan senyawa aktif, selanjutnya senyawa tersebut dilihat interaksi molekuler dengan enzim α-glukosidase secara in silico kemudian dibuktikan secara in vitro. Penelitian ini bertujuan untuk mempelajari interaksi molekuler antara senyawa bioaktif daun sirih merah terhadap enzim α-glukosidase secara in silico serta menentukan tipe penghambatan ekstrak dan fraksi daun sirih merah terhadap enzim α-glukosidase secara in vitro. Ekstraksi dilakukan dengan metode maserasi menggunakan etanol 70%, kemudian ekstrak difraksinasi bertingkat menggunakan 3 jenis pelarut, yaitu n-heksana, etil asetat dan air. Penambatan molekuler senyawa bioaktif yang diisolasi dari daun sirih merah (Piper crocatum) dengan enzim α-glukosidase menggunakan autodock vina, diperoleh nilai binding affinity dan Ki. Hasil pengujian secara in silico kemudian dibuktikan secara in vitro untuk menentukan aktivitas penghambatan daun sirih merah terhadap enzim α-glukosidase dan menentukan tipe penghambatan dengan persamaan Dixon menggunakan dua konsentrasi substrat (10 mM dan 15 mM). Hasil uji in silico menunjukkan bahwa senyawa aktif yang berperan dalam menghambat enzim α-glukosidase adalah Columbin. Columbin berikatan di situs pengikatan dengan asam amino Ser240, Asp242, His280, Arg315, Glu411, Phe159, Arg442, Tyr158 dan Phe303. Hasil in vitro menunjukkan nilai IC50 terbaik diperoleh untuk fraksi etil asetat pada konsentrasi 743.80 μg/mL, dengan mekanisme penghambatan kompetitif. Berdasarkan hasil pengujian secara in silico maupun in vitro menunjukkan hasil yang serupa, dimana tipe penghambatan daun sirih merah kompetitif dengan senyawa yang diduga berperan sebagai inhibitor adalah columbin.
Keyword: Columbin, In Vitro, In Silico, Penghambatan α-Glukosidase

Judul: Penambatan molekuler senyawa bioaktif sirih merah (Piper crocatum) terhadap lipoksigenase dan penghambatan malondialdehid in vitro
Abstrak: Penyakit degeneratif terjadi karena beberapa faktor risiko yang berhubungan langsung dengan peradangan. Salah satu agen penyebab inflamasi adalah enzim lipoxygenase (LOX) yang dapat membentuk malondialdehid (MDA) sehingga dibutuhkan obat antiinflamasi yang terbuat dari tanaman herbal salah satunya daun sirih merah (Piper crocatum). Penelitian ini bertujuan menentukan senyawa asal dari ekstrak dan fraksi etanol 70% daun sirih merah yang memiliki penghambatan terbaik terhadap enzim lipoksigenase penyebab terbentuknya malondialdehid (MDA) melalui simulasi penambatan molekuler serta menentukan aktivitas antioksidan tertinggi dari 4 daerah berbeda di pulau Jawa dengan metode thiobarbituric acid (TBA). Senyawa daun sirih merah yang mampu menghambat enzim lipoksigenase yakni ligan nandrolone phenylpropionate dan sofalcone dengan energi afinitas sebesar -10.4 kkal/mol dan -9.1 kkal/mol dengan nilai Ki sebesar 0.0023 µM dan 0.021 µM. Aktivitas antioksidan daun sirih merah terbaik dari daerah asal Bogor ekstrak etanol 70% dengan nilai IC50 sebesar 0.432 µg/mL. Perbedaan kekuatan antioksidan tiap daerah dilakukan analisis PCA dengan hasil tidak terbentuk kluster sehingga antar daerah memiliki karakteristik yang sama, Degenerative diseases occured due to several risk factors which directly related to inflammation. One of the causative agents of inflammation is the lipoxygenase (LOX) enzyme which can form malondialdehyde (MDA) so that anti-inflammatory drugs are needed made from herbal plants such as red betel leaf (Piper crocatum). This study aimed to determine the origin of the compound from the 70% ethanol extract and fraction of red betel leaf which had the best inhibition of the lipoxygenase enzyme that causes malondialdehyde (MDA) formation through molecular docking simulations and to determine the highest antioxidant activity from 4 different areas in Java islands with thiobarbituric acid (TBA) method. Red betel leaf compounds that can inhibited lipoxygenase enzymes are nandrolone phenylpropionate and sofalcone ligands with affinity energies of -10.4 kcal/mol and -9.1 kcal/mol with Ki values of 0.0023 µM and 0.021 µM, respectively. The best antioxidant activity of red betel leaf came from Bogor of 70% ethanol extract with an IC50 value of 0.432 µg/mL. The difference in antioxidant strength of each region was carried out by PCA analysis with the results no clusters were formed so that between regions had the same characteristics.
Keyword: Antioksidan, Daun Sirih Merah, Lipoksigenase, Malondialdehid

Judul: Characteristic of Overshooting Top (OT) Based on  Himawari  8  Satellite  as  a  Convective  Cloud  Feature  that  Generates  Extreme Weather in the Java Island Region
Abstrak: Overshooting Top (OT) is a feature at the top of a convective cloud that is associated with extreme weather. Research on OT in tropical Indonesia is still very limited. The existence of geostationary satellites with wide area coverage and fast frequency observations is useful for observing the fast dynamics of the OT life cycle. Therefore, this study intends to analyze the relationship between OT and extreme weather, updraft and thermodynamic conditions of OT when extreme weather occurs, the best objective method for detecting OT in the day time and night time, and the spatiotemporal distribution of OT in the tropical region of Java Island during the 2018-2021 period. Based on visual analysis using visible channel and Himawari 8 sandwich products, 87% of extreme weather events in Java were accompanied by the appearance of OT. It indicates that the presence of the OT pattern is a convection cloud pattern or feature that is closely related to extreme weather events for the Java Island region. The existence of a time lag between the appearance of OT and extreme weather events on Java Island indicates that the OT of convection cloud can be used as a precursor or nowcasting for the appearance of extreme weather. Most of the convective cloud OT features during extreme weather events on Java Island have altitude that were only able to exceed the altitude of the equilibrium level and few were able to exceed the tropopause level of 9 km – 16 km. The difference in atmospheric conditions during extreme weather events on Java Island, which is in the tropics and subtropics, is a strong and unstable convective energy condition characterized by a larger CAPE, as well as unstable KI, LI, SI and TTI values. It is offset by kinematic factors in the form of a weak vertical wind shear (bulk wind shear 0-6 km) and a higher freezing point height. The difference between extreme weather events in the Java Island region and other tropical regions compared to subtropical regions is the strong updraft speed of convection clouds. The IRW Texture COMB algorithm based on the IRW-Texture Gradient modification and the COMB algorithm shows a significant increase in quality for detecting OT and non-OT pixels in Java. Rainy days with rainfall > 50 mm/day are very common in areas with an altitude of > 500 m. On the other hand, the level of convection activity which is indicated by the presence of OT and lightning is significantly reduced in this area. OT of convective clouds appear more frequently during the DJF season and less frequently during the JJA season. OT often appears during the day time and rarely at night time. Most OTs appear in the central part, away from the south and north coasts of Java Island during the day, while OTs that appear near the south and north coasts of Java Island can appear in the morning or afternoon.
Keyword: convective clouds, extreme weather, Overshooting Tops, Himawari 8 Satellite