Judul: Kandungan Kurkuminoid, Inhibisi a-Glukosidase dan Sitotoksisitas Ekstrak dari Beberapa Aksesi Kunyit (Curcuma domestica Val.)
Abstrak: Turmeric (Curcuma domestica Val.) is a medicinal plant family Zingiberaceae with curcuminoid content of the rhizome. This study aims to determine the content of curcuminoid, α-glucosidase inhibitory activity, and cytotoxicity test curcuminoids of turmeric extracts from several accessions. Curcuminoid content analysis was performed using HPLC. Inhibition of α- glucosidase performed in vitro with the substrate p-NPG. The cytotoxicity of curcuminoid extract of turmeric using BSLT method. The highest levels of curcuminoid owned by Ngawi, followed by Ciemas, Wonogiri, and Nagrak. Levels curcuminoids Ngawi of 24.50%. Turmeric extract the highest bioactivvity as α-glucosidase inhibitor activity is Nagrak accession with IC50 values of 207.093 μg/mL. Cytotoxycity test results showed that all samples have bioactivity and accession have the best LC50 value is Karanganyar at 19.090 μg/mL. Nagrak, Wonogiri, and Ngawi, has the potential to be developed into new varieties of turmeric with high bioactivity in inhibition α-glucosidase with IC50 moderate level.
Keyword: Bogor Agricultural University (IPB), turmeric, cytotoxicity, curcuminoids, α-glucosidase

Judul: Kandungan Kurkuminoid dan Daya Antioksidan Aksesi Temulawak (Curcuma xanthorrhiza Roxb.) asal Sukabumi
Abstrak: Curcuma xanthoriza Roxb. is one kind of curcums which useful as medicine plants. It containts curcuminoid which has antioxidant bioactivity. This study aimed to measure curcuminoids content and antioxidant bioactivity of Ciemas (Sukabumi) accessions compared with varieties of Kursina 3 from Bogor. HPLC method were used to determined curcuminoid content. The antioxidant bioactivity of both samples were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical method. Percent yield ethanol 70 % extract of Curcuma xanthoriza Roxb. were 15.85 % (Kursina 3) and 19.94 % (accession). The curcuminoid content of Kursina 3 and acccession were 0.79 % and 0.99 %, respectively. The result of IC50 were 82.8 ppm (Kursina 3) and 47.97 ppm (accession) respectively. Based on the result of the study, Sukabumi promising lines curcuma has the potential to be further researched and developed as new varieties.
Keyword: antioxidant, Curcuma xanthoriza Roxb, curcuminoid.

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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