Judul: Antihiperurisemia Ekstrak Sidaguri, Seledri, dan Tempuyung secara In Vitro dan In Vivo
Abstrak: Celery (Apium graveolens), sidaguri (Sida rhombifolia), and tempuyung (Sonchus arvensis) are an Indonesian native medicinal plants that can augment the production of urine (diuretic) and can inhibit xanthine oxidase enzyme activity in order to decrease the level of uric acid in blood. Inhibition of xanthine oxidase by in vitro was examined at the optimum condition (20 oC of incubation temperature, pH 7.5, 0.1 unit/ml of xanthine oxidase concentration, and 0.7 mM of xanthine concentration) was compared with allopurinol as positive control. The results of in vitro inhibition test of xanthine oxidase activity showed single extract of 400 ppm of sidaguri, 1400 ppm of celery, and 400 ppm of tempuyung that have greatest inhibition of 56.46, 80.95, and 83.02%, respectively. In addition, the combined extract of sidaguri, celery, and tempuyung of 4:14:4 ratio showed inhibition of 88.68%. The combination with dose of 2640 mg/300 g BB can decrease the concentration of uric acid in the blood of rat by 56.86% which exceeds the positive control (allopurinol) of 56.86%, and has xanthine oxidase activity of 179.05 mM/L min lower as compared with the normal group (501.12 mM / L min). These results proved that the combined extracts of sidaguri, celery, and tempuyung is potential as antigout medicine through xanthine oxidase enzyme inhibition.
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Judul: Kinetika Inhibisi Flavonoid Sidaguri (Sida rhombi/alia L.) Terhadap Enzim Xantin Oksidase
Abstrak: Sidaguri is one of the traditional medicinal plants that has a potency as antigout. It has been reported that flavonoid from sidaguri could inhibit activity of x~hine oxidase enzyme (causes gout) up to 55,29% (Iswantini & Darusman, 200~ The aim of this research is to investigate the type of sidaguri's flavonoid crud~ extract kinetic inhibition and the effects of purification on inhibitory poterWY that have never been studied. The result of this research showed that sidagWi's extraction has yielded 11,85% flavonoid crude extract (LCso 501,23 ppm)~ith inhibitory effect from 47,71 % until 70,71% (100-800 ppm). Generally, the eSract has a good potential as gout medicine although it was tested in low conc~tration from the extract's toxicity rate. The kinetic inhibition of 200 ppm crudeDextract caused the increment ofKM (1,15 mM or increase 132%) from 0,87 roM i> 2,02 roM and without changed of V max. Based on that, the type of VI inhibinon is competitive inhibition (Webb 1963). Purification yielded 11 fracti~s and the highest activity came from fraction 4 (inhibitory effect of 79,09!'o). The purification has caused low increase of potent inhibitory effect. Fract~n 3 with 100 ppm has a bit higher inhibitory effect (51,58%) compare to the cI!oe extract at same concentration (47,71%) or increase 8,11%. In general the poten1l:linhibitory effect from purification result has lower strength compare to the 100 Ifm crude extract. GC-MS analysis from fraction 4 showed that there were 39 or..gruric compounds with BM estimation of 152-454 glmol. Based on FT-IR and GC-MS analysis, strengthened with phytochemical test we estimate that the potential compound with xanthine oxidase inhibitory activity is flavonoid compound.
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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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