Judul: Optimisasi Ekstraksi Daun Dandang Gendis Menggunakan Parameter Waktu, Nisbah Sampel-pelarut, dan Jenis Pelarut
Abstrak: This study was started with soxhlet extraction of the dried leaves of dandang gendis with n-hexane and then maceration of the residue. Optimization on the maceration process was carried out by varying the maceration time, ratio of sample-solvent, and solvent to obtain the lowest LC50 value. The dried leaves sample used here has 9.75% moisture content. The extraction yields obtained were varying from 13 to 18% and the brine shrimp lethality test showed that the LC50 values of the extracts were 275 to 650 mg/L. The response surface method was used to see the treatment effect to the response (e.g. LC50). The method was calculated using Minitab 15 and SAS 9.1 softwares. From these calculations, the optimum condition for the leaves of dandang gendis extraction was achieved by using 20% ethanol as solvent, 1:3 samples to solvent ratio, and 6 hours of maceration. The LC50 value of the optimum extracting condition was 240.66 mg/L. The phytochemical assay results showed that the most active the leaves of dandang gendis extract contained saponins, flavonoids, and alkaloids.
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Judul: Uji Toksisitas Ekstrak Etil Asetat Teraktif Daun Dandang Gendis (Clinacanthus nutans) Menggunakan Uji Letalitas Larva Udang
Abstrak: Dandang gendis (Clinacanthus nutans) is a medical herb commonly used as a traditional medicine as antimalarial and antidiabetic. This study was started with maceration of the dried leaves of dandang gendis with ethanol,and then partitioned using n-hexane. The ethanol extract free of nonpolar compounds was then partitioned with ethyl acetate. The ethanol crude extract, n-hexane fraction, and ethyl acetate fraction were tested by using brine shrimp lethality test to determine the toxicity of each extract. The ethyl acetate fraction showed the highest activity with 50% lethal concentration (LC50) of 32 mg/L. Re-extraction of ethanol extract free of nonpolar compounds by using ethyl acetate in 90 minutes by three times extraction with material:solvent ratio of 1:2 resulted LC50 value of 29.02 mg/L. Phytochemical assay results showed that the ethyl acetate extract of dandang gendis leaves contained saponins, alkaloids, steroids, and flavonoids. Re-extraction of ethyl acetate extract contained higher flavonoids than ethyl acetate extract from the first extraction.
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Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology