Judul: Aktivitas antioksidan ekstrak selaginella
Abstrak: Selaginella (Selaginellaceae) is a pteridophyte plant, having a lot of potential and benefits as food material and pharmaceutical. As a medicinal plant, Selaginella has been used as anti-cancer, anti-tumor, and antioxidant. The objective of the study was to analyze the potential of S. ornata, S. plana, and S. willdenovii extract as antioxidant by measuring lipid peroxidation (MDA level) and Superoxide Dismutase (SOD) activity. This experiment was started with LD50 test of three kinds of Selaginella extract as preliminary experiment. The experiment was designed as complete randomize design with two factors. The first factor was three species of Selaginella and the second factor was four doses of Selaginella extracts, which were 0, 0.3, 0.6, and 1.2 g extract/kg bw. The result showed that at the dose of 0.6 g extract/kg bw, Selaginella extract could decrease the MDA level to the lowest level. The dose of 0.3 g extract/kg bw could increase the SOD activity. Among the three species of Selaginella extract, S. ornata showed the best antioxidant activity.
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Judul: Metabolomic Analysis of Selaginella spp. (Selaginellaceae) and its Potential as Medicinal Plants
Abstrak: Selaginella merupakan salah satu marga tumbuhan paku dari suku Selaginellaceae yang memiliki keragaman spesies yang tinggi di daerah tropis dan subtropis. Selaginella memiliki potensi dan manfaat yang cukup besar terutama dalam bidang kesehatan, khususnya dapat dimanfaatkan sebagai tumbuhan obat. Namun, informasi metabolit pada Selaginella spp. masih terbatas. Penelitian ini bertujuan menganalisis metabolit pada Selaginella spp. yang dapat dimanfaatkan sebagai obat dan dapat digunakan sebagai pembeda antar spesies. Metode penelitian yang dilakukan meliputi preparasi sampel, ekstraksi sampel, analisis kandungan metabolit dengan LC-MS/MS, dan analisis data. Analisis metabolomik meliputi identifikasi metabolit menggunakan perangkat lunak MZmine 3.1.0 beta, analisis profil metabolit, klaster heatmap, dan analisis gugus menggunakan MetaboAnalyst 5.0. Hasil analisis menunjukkan sebanyak 113 metabolit terdeteksi pada tiga spesies Selaginella yang diamati. Analisis gugus berdasarkan ciri metabolit mengelompokan seluruh individu menjadi 3 kelompok sesuai dengan spesiesnya. Metabolit Selaginella willdenowii lebih mirip Selaginella ornata dibandingkan dengan Selaginella plana. Beberapa senyawa yang terdeteksi memiliki manfaat penting dalam bidang pangan, kesehatan, dan kecantikan. Senyawa aloeresin a, naringin, rhoifolin, isoschaftoside, isovitexin 2''-oarabinoside, 4-vinylphenol, dan isofraxidin merupakan kandidat penanda kimia pada Selaginella plana. Senyawa velutin, aspalathin, 2-hydroxybenzaldehyde, gardenin a, catechol, dan n-(1,1-dimethyl-3-oxobutyl)acrylamide merupakan kandidat penanda kimia pada Selaginella ornata. Senyawa kapakahine b, dihydrojasmonic acid, linoleic acid, alantoic acid, menaquinone, dan nandrolone merupakan kandidat penanda kimia pada Selaginella willdenowii., Selaginella is a genus of Pteridophyta from the Selaginellaceae which has high diversity in tropical and subtropical areas. Selaginella has considerable potential and benefits, particularly it can be used as a medicinal plant. However, information on metabolites in Selaginella spp. is still limited. This study aimed to analyze the metabolite compounds in Selaginella spp. which can be used as medicine and as a biomarker to differentiate among species. The research methods included sample preparation, sample extraction, analysis of metabolite content by LC-MS/MS, and data analysis. The metabolomic analysis included the identification of metabolites using MZmine 3.1.0 beta software, analysis of metabolite profiles, and cluster analysis using MetaboAnalyst 5.0. The results of the analysis showed that as many as 113 different metabolites were detected in the three Selaginella species. Metabolite based cluster analysis grouped all individuals into 3 groups according to the species. Selaginella willdenowii metabolites are more similar to Selaginella ornata than Selaginella plana. Some of the metabolites detected have important benefits for food, health, and beauty. Aloeresin a, naringin, rhoifolin, isoschaftoside, isovitexin 2''-o-arabinoside, 4- vinylphenol, and isofraxidin compound are candidate chemical markers in Selaginella plana. Velutin, aspalathin, 2-hydroxybenzaldehyde, gardenin a, catechol and n-(1,1-dimethyl-3-oxobutyl)acrylamide compound are candidate chemical markers in Selaginella ornata. Kapakahine b, dihydrojasmonic acid, linoleic acid, alantoic acid, menaquinone, and nandrolone compound are candidate chemical markers in Selaginella willdenowii.
Keyword: cluster analysis, heatmap, LC-MS/MS, metabolite

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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