Judul: Aktivitas Antioksidan Dan Potensi Hayati Dari Kombinasi Ekstrak Empat Jenis Tanaman Obat Indonesia
Abstrak: The crude ethanol extracts combination of four Indonesia medicinal plants namely Curcuma xanthorriza, Phyllanthus niruri, Andrographis paniculata, and Curcuma aeruginosa were examined for their antioxidant (radical scavenging) activity using 2,2-diphenyl-1-picrylhidrazyl (DPPH) free radical and biological activities or cytotoxicity using brine shrimp lethality test (BSLT). IC50 values for DPPH radical scavengeing activity ranged from 1.923 to 211.127 ppm, with extract combination of Curcuma xanthorriza and Curcuma aeruginosa (1:0:0:1) having the lowest value and therefore the most potent, and extract combination of Phyllanthus niruri, Andrographis paniculata, and Curcuma aeruginosa (0:1:1:1) having the highest value. LC50 values for BSLT ranged from 31.796 to 620.165 ppm, with extract combination of Curcuma xanthorriza, Phyllanthus niruri, Andrographis paniculata, and Curcuma aeruginosa (1:1:1:1) having lowest value and therefore the most potent, and extract of Curcuma aeruginosa (0:0:0:1) having the highest value. A positive correlation between antioxidant and biological activities of extract combination was obtained from combination (1:1:1:1), with antioxidant and biological or cytotoxicity values were 41.87 and 31.79 ppm, respectively.
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Judul: Profil Kimiawi dari Formulasi Ekstrak Meniran, Kunyit, dan Temulawak Berdasarkan Aktivitas Antioksidan Terbaik
Abstrak: Indonesia is known as a megabiodiversity countries with the title because it has such biodiversity of flora and fauna. Flora or plant widely used as medicine by traditional means, namely phyllanthin, curcuma, and turmeric. Phyllanthin, curcuma, and turmeric extracts are the plant extracts which contains antioxidant activity. This study aimed to evaluate the antioxidant activity of the formulation phyllanthin, turmeric, and curcuma. Phyllanthin, curcuma, and turmeric is extracted using 96% ethanol and extract formulation carried M:K:T ratio of 1:1:1, 1:1:0, 1:0:1, 0:1:1, 1:0 : 0, 0:1:0, and 0:0:1. Extract formulation phyllanthin: curcuma: turmeric (M:K:T) tested the antioxidant activity with DPPH method. Extracts formulation of which have the highest antioxidant activity of the chemical profile was analyzed by TLC and FTIR. Antioxidant activity which have the highest to explained from extract formulation M:K:T = 1:0:0, 1:1:0, dan 1:0:1 by IC50 percentage antioxidant activity are 33.42 ppm, 45.52 ppm, dan 57.65 ppm. TLC chromatogram profiles obtained from formulations M:K:T = 1:1:0, 1:0:1, and 1:0:0 showed the number of spots as much as 10, 8, and 7 spots. FTIR spectrum results showed functional groups of O-H stretching, C-H stretching, C=C stretching and C=C bending in each formulation which have the highest antioxidant activity.
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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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