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: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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