Judul: Clusterization of P. crocatum Leaf (Piper crocatum) from Various Regions in Indonesia Based on Secondary Metabolite Fingerprint Analysis and Cytotoxicity Values
Abstrak: Kualitas ekstrak etanol daun sirih merah sebagai tanaman obat ditentukan oleh metabolit sekunder yang dipengaruhi oleh kondisi geografis dan lingkungan tumbuh tanaman. Penelitian ini bertujuan untuk mengelompokkan sirih merah dari berbagai daerah di Indonesia berdasarkan analisis sidik jari metabolit sekunder dan nilai sitotoksisitas. Pengamatan keragaman matabolit sekunder ekstrak etanol daun sirih merah berasal dari tujuh daerah berbeda (Banda Aceh, Bandung, Bogor, Malang, Samarinda, Kendari, Jayapura) yang dilakukan dengan pendekatan metabolomik menggunakan kromatografi cair-spektroskopi massa (LC-MS/MS) dan penentuan nilai sitotoksisitas dengan metode Brine Shrimp Lethality Test (BSLT). Analisis sidik jari metabolit sekunder menggunakan analisis kluster dengan dendrogram menghasilkan 12 senyawa dengan 3 kelompok sampel berdasarkan daerah asalnya yaitu kelompok 1 (Banda Aceh, Samarinda, Jayapura); kelompok 2 (Bandung, Kendari, Malang); kelompok 3 (Bogor). Sampel kelompok 1 teridentifikasi 8 senyawa yang memiliki nilai kelimpahan relatif tertinggi. Sampel kelompok 2 teridentifikasi 3 senyawa yang memiliki nilai kelimpahan relatif tertinggi. Sampel kelompok 3 memiliki 1 senyawa dengan nilai kelimpahan relatif tertinggi. Masing-masing senyawa memiliki waktu retensi yang berbeda-beda. Nilai sitotoksisitas (LC50) ekstrak etanol daun sirih diperoleh ekstrak paling aktif berasal dari daerah Banda Aceh dan Malang (2,64 μg/mL). Simpulan dari penelitian ini berdasarkan hasil analisis sidik jari metabolit sekunder dan nilai sitotoksisitas teridentifikasi 12 senyawa dengan tiga kluster keragaman metabolit sekunder berdasarkan daerah asalnya yaitu kelompok 1 (Banda Aceh, Jayapura, Samarinda); kelompok 2 (Bandung, Kendari, Malang); kelompok 3 (Bogor).
Keyword: LC-MS/MS, LC50, Piper crocatum

Judul: Profil Flavonoid, Tanin, dan Alkaloid dari Ekstrak Daun Sirih Merah (Piper crocatum)
Abstrak: Piper crocatum is Indonesia’s medicinal plant that has been proven to have anti-hyperglycemic, antioxidative, and anticancer activities. Hence, the aim of this study was to determine and analyze flavonoid, tannin, and alkaloid profiles of 30 % ethanol and water extracts of Piper crocatum leaves. Flavonoid, tannin, and alkaloid profiles were measured using spectrophotometry, titrimetry, gravimetry and LC-MS techniques. Phytochemical identification proved that both of extracts contain flanovoids, tannins, and alkaloids. Measurement of flavonoids quantitatively showed that the highest value was found in ethanol 30 % extract, 6.09 ± 0.26 mg QE/g. The highest quantitative tannin and alkaloid present in the water extract with a value of 3.97 ± 0.08 mg/g and 543.75 ± 3.17 mg/g. LC-MS analyze, the highest flavonoid compounds expected in water extract. The highest tannin and alkaloid compounds were expected in ethanol 30 % extract.
Keyword: tannins., Piper crocatum, flavonoids, alkaloids

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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