Judul: Ekstraksi Senyawa Aktif Antioksidan dari Lintah Laut (Discodoris sp.) asal Perairan Kepulauan Belitung.
Abstrak: Radikal bebas terbentuk secara terus-menerus dalam tubuh manusia, baik melalui pengaruh eksogen maupun endogen. Radikal bebas adalah senyawa kimia yang memiliki satu atau lebih elektron tidak berpasangan di kulit terluar sehingga sangat reaktif dan mampu bereaksi dengan protein, lipid, atau DNA. Reaktivitas radikal bebas ini dapat diredam oleh senyawa antioksidan. Antioksidan sintetik yang berkembang saat ini dikhawatirkan memberi efek samping yang berbahaya bagi kesehatan manusia. Potensi antioksidan alami harus dikembangkan untuk memperoleh antioksidan yang lebih aman dikonsumsi. Salah satu sumber daya perairan yang berpotensi sebagai penghasil antioksidan alami adalah lintah laut (Discodoris sp.).
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Judul: Ekstraksi dan identifikasi senyawa bioaktif lintah laut (Discodoris sp.) sebagai antioksidan
Abstrak: One of the commodities produced from the ocean that have a bioactive compounds is a sea slug (Discodoris sp.). That is very interesting to study mainly deals with the nature of both chemical and biochemical characteristics and their use for the field of food and health. The purpose of this study is to determine the nutrient content of sea slug, determine antioxidant activity, and determine the bioactive compounds of sea slug. The experiment was conducted with several stages: sample preparation, extraction bioactive compound, fractionation by TLC and identification of compounds by GC-MS. Sea slug from the island of Madura Pamekasan potential as a source of protein, fat, and minerals. Sea slug has esensial amino acids amount to 5,57% was dominated by leucin of 1,42%. Nonesensial amino acids amount to 6,54% wich was dominated by glutamic acid 2,19%. Saturated fatty acids amounted to 27.53% of sea slug was dominated by palmitic (C16:0) which was 13.36%. Unsaturated fatty acids amounted to 34.66%, which was dominated by the essential fatty acids linolenic (C18:3, n-3) 20.91%. The highest yield of the crude extract was ethanol of 6,97% and contained alkaloid, steroids, saponin, phenols, carbohydrates and reducing sugar compound. The bioactive compounds in the meat of sea slug with ethanol solvent was galoxolide, dibuthyl phthalate, di-n-octhyl phthalate, oleic acid amide, erucylamide, squalene and has an IC50 best antioxidant activity in fraction 5 at 150.92 ppm.
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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