Judul: Acute Toxicity Test of Active Fruit Extract from Soursop (Annona muricata) and Pond Apple (Annona glabra) as an Anticancer Potential.
Abstrak: Penelitian khasiat antikanker dari berbagai bagian tumbuhan sirsak telah marak dilakukan, namun penelitian khasiat antikanker dari bagian buah masih jarang dilakukan. Buah sirsak yang cukup banyak terdapat di Indonesia adalah buah sirsak ratu (Annona. muricata) dan buah sirsak hutan (A. glabra). Penelitian toksisitas dari buah sirsak ratu dan buah sirsak hutan dilakukan dengan dua metode, yaitu metode uji letalitas larva udang (BSLT) dan metode lebih terkini dengan menggunakan embrio ikan zebra (Danio rerio). Nilai LC50 terbaik dari ekstrak buah sirsak ratu dan sirsak hutan diberikan oleh ekstrak etil asetat baik dengan menggunakan metode BSLT maupun dengan embrio ikan zebra. Hasil pengamatan embrio ikan zebra melaporkan bahwa ekstrak etil asetat sirsak ratu merupakan ekstrak dengan daya sitotoksik tertinggi. Uji fitokimia dari ekstrak etil asetat masing-masing buah menghasilkan uji positif pada golongan senyawa alkaloid, tanin, dan flavonoid. Ekstrak etil asetat sirsak ratu menghasilkan 6 noda dari hasil pemisahan dengan kromatografi lapis tipis dan ekstrak etil asetat sirsak hutan menghasilkan 8 noda dengan cara yang sama.
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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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