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: Bioaktivitas Antioksidan dan Antiinflamasi Secara In Vitro serta Kandungan Kurkuminoid Temulawak dan Kunyit Asal Sukabumi
Abstrak: Curcuma xanthorrhiza and Curcuma domestica are kind of medicinal plants which have many health benefits. Both of them have curcuminoid content which is useful as an antioxidant and anti-inflamatory. In this study, ethanol extracts of C. xanthorrhiza and C. domestica promising lines from Sukabumi, Indonesia were investigated for the presence of curcuminoids, antioxidant and anti-inflamatory activities. HPLC method were used to determined curcuminoids content. The antioxidant (radical scavenging) potential of the samples was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical method. While for the anti-inflamatory activity, the in vitro cyclooxygenase 2 (COX2) inhibition method was used. The curcuminoid content of C. xanthorrhiza and C. domestica were 31.27 mg/g and 66.32 mg/g, respectively. IC50 values for DPPH radical scavenging activity were 81.99 μg/mL and 73.31 μg/mL, with C. domestica having lowest value and most potent than C. xanthorrhiza. Percent inhibition values for COX2 inhibitor activity were 74.84 % and 67.96 %, with C. domestica having the highest value. In this study, the ethanol extracts of C. domestica promosing line from Sukabumi of Indonesia exhibited most in curcuminoids content, antioxidants properties and anti-inflamatory activity than C. xanthorrhiza promosing line.
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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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