Judul: Activities of suren (Toona sinensis Merr.) bark extracts as antioxidant and antidiabetic with in vitro analysis.
Abstrak: Suren (Toona sinensis Merr.) is a herbal plant that its leaves has been reported have a antioxidant and antidiabetic activity. The bark of suren thought to have antioxidant and antidiabetic activity as it leaves. This study was conducted to investigate antioxidants and antidiabetic activity of ethanol 70% and water extracts of suren bark using in vitro method. The antioxidant activity was observed using the parameters of biochemical tests, through measurement of the inhibitory activity to DPPH as free radical with concentration of samples 50, 30, 10, and 5 ppm. The potential antidiabetic activity was measured through inhibition of -glucosidase enzymes work at a sample concentration of 12.5, 6.3, 3.1, and 1.6 ppm. The moisture content of suren bark samples in the test is 9.04%. Suren bark extracted with a solvent ethanol 70% and water has a yield of 4.8% and 2.6%. Phytochemical test of ethanol 70% extract showed the present of alkaloids, saponins, tannins, flavonoids, and hydroquinone. While the water extract indicate a content of saponin compounds, flavonoids, and hydroquinone. The results of the analysis of antioxidant activity indicated by IC50 value which is 11.86 ppm for ethanol 70% extracts and 17.78 ppm for water extract. While the IC50 value of vitamin C used as a comparison is 3.31 ppm. Inhibition of - glucosidase enzyme are also shown in the IC50 value which is 0.66 ppm for ethanol 70% extract and 3.32 ppm for water extracts, whereas acarbose as a comparison have IC50 value of 0.08 ppm. These results showed that suren bark have an antioxidant and antidiabetic activity. Key words: antioxidant, antidiabetic, suren (Toona sinensis Merr.) DPPH, a- glucosidase
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Judul: Antidiabetic Potency of Suren (Toona sinensis) Bark Extract in Alloxan Induced Sprague-Dawley Rats.
Abstrak: Suren (Toona sinensis) merupakan tanaman yang hampir semua bagian-bagiannya memiliki khasiat untuk pengobatan. Daun dan kulit batangnya juga telah dilaporkan memiliki efek antioksidan dan telah diuji secara in vitro maupun in vivo. Tujuan dari penelitian ini adalah untuk mengetahui potensi ekstrak etanol 70% kulit kayu suren sebagai senyawa antidiabetes secara in vivo dengan menggunakan tikus Sprague-Dawley. Ekstraksi dilakukan dengan proses perendaman atau maserasi. Pengujian secara in vivo dilakukan dengan membandingkan efek pengobatan dari ekstrak kulit kayu suren dosis 150 mg/kg bobot badan dan 300 mg/kg dengan glibenklamida dosis 2.5 mg/kg bobot badan. Parameter uji yang diamati adalah yaitu konsumsi pakan pada masa adaptasi dan perlakuan, bobot badan pada masa adaptasi dan perlakuan, kadar glukosa darah selama masa perlakuan, dan hasil pengamatan histopatologis pankreas. Rendemen yang dihasilkan dengan ekstraksi etanol 70% adalah 4.8%. Hasil pengamatan terhadap kadar glukosa darah tikus menunjukkan bahwa pencekokan ekstrak kulit kayu suren dosis 150 mg/kg BB menghasilkan persentase penurunan kadar glukosa darah paling tinggi, sebesar 70.82%. Sementara itu, dosis 300 mg/kg BB dan glibenklamida masing-masing menunjukkan penurunan persentase kadar glukosa darah sebesar 51.96% dan 68.92%. Hasil pengamatan histopatologis memperlihatkan bahwa pankreas tikus yang diberi ekstrak kulit kayu suren dosis 150 mg/kg BB memiliki kondisi yang lebih baik dibanding kelompok perlakuan lainnya
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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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