Judul: Toksisitas Akut Ekstrak Daun Sirsak Ratu (Annona muricata) dan Sirsak Hutan (Annona glabra) sebagai Potensi Antikanker
Abstrak: Soursop plants has been known to have pharmacological activities such as anticancer. Soursop species that are widely found in Indonesia are soursop (Annona muricata) and pond apple (A. glabra). This study has determined the toxicity properties of leaf extracts of these species to brine shrimps larvae and zebra fish embryos. Overall, the pond apple extract showed higher toxicity then the soursop. The best LC50 values were obtained from hexane extract of pond apple leaves, namely 197 μg/mL to brine shrimps larvae and 326 μg/mL to zebra fish embryo. These values indicate a significant correlation as anticancer compounds. This extract of pond apple resulted 8 spots in separation by using thin layer chromatography. 1H-NMR measurement towards these 2 well-separated spot did not show acetogenin component, as previously reported as the anticancer components in soursop plants. Further fractionation of the extract is needed to ensure the structure of the anticancer active component it contained.
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Judul: Pencirian Ekstrak Aktif Sitotoksik dari Daun Sirsak Gundul (Annona glabra) Indonesia
Abstrak: Pond apple (Annona glabra) is a member of Annonaceae. It has been reported that plants from Annonaceae family contains alkaloid, flavonoid, and acetogenin having good anticancer potency. The objectives of this research were to fractionate A. glabra leaves assisted with brine-shrimp lethality test (BSLT), to characterize the active extract, and to identify the phytochemical constituents. Fractionation of 95% ethanol extract using liquid-liquid extraction gave 7 fractions, namely yellow, orange, and dark water, chloroform, residue, hexane, and methanol fractions. Based on the BSLT results, chloroform fraction showed the highest activity with LC50 of 98 ppm. Phytochemical test of the most active fraction showed alkaloid, flavonoid, steroid, triterpenoid, and tanin components. Subsequent fractionation of the chloroform fraction by using hexane-CH2Cl2-methanol (90:40:5) eluent produced 16 spots. The infrared spectrum of the best separated spot was analyzed and showed functional groups with -OH, aromatic C=C, C-H sp2, and C-H sp3 bonds.
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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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