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: Optimisasi Ekstraksi Cair-Cair Fraksi Etanol Daun Dandang Gendis (Clinacanthus nutans)
Abstrak: Dandang gendis (Clinacanthus nutans) is a herb which contains antimalaria and larvacide bioactive compounds. In this study, the dried leaf powder was macerated with ethanol and then partitioned with n-hexane. The resulting ethanol extract was then partitioned again with ethyl acetate and this liquid-liquid extraction procedure was the subject of the optimization. Sample to solvent ratio (1:2, 1:3, and 1:4 (mL/mL), extraction temperature (30, 40, and 50 °C); and extraction repetition (1, 2, and 3 times) variations effect were studied. The bioactivity of the extracts were tested with brine shrimp lethality test (BSLT) using Artemia salina. The BSLT result of the 11th extract showed the optimum LC50 value (59.15 mg/L). This extract was obtained from the extraction procedure using 1:4 (mL/mL) sample to solvent ratio, 40 °C temperature, and 3 times repetition. From the Minitab 15 computation results were predicted that the optimum condition is achieved at 1:3.88 – 1:4.00 (mL/mL) sample to solvent ratio, 4.61 – 49.99 °C extraction temperature, and 3 times extraction repetition with LC50 170.19 mg/L. The phytochemistry test results showed that the 11th extract contains alkaloids, flavonoids, saponins, and steroids.
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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