Judul: Antioxidant Activity and Bioactive Compound of Rhizophora mucronata as herbal tea preparations
Abstrak: Rhizophora mucronata merupakan jenis mangrove yang banyak dijumpai di Indonesia. R. mucronata memiliki kandungan senyawa bioaktif yang potensial untuk dimanfaatkan untuk menangkal radikal bebas. Penelitian ini bertujuan menentukan senyawa bioaktif serta aktivitas antioksidan yang terkandung dalam daun, bunga dan buah R. mucronata. Penelitian meliputi karakterisasi daun, bunga dan buah segar serta kering, serta menentukan kandungan fitokimia, total fenol dan aktivitas antioksidan ekstrak R. mucronata. Ekstrak bunga memiliki aktivitas antioksidan tertinggi 55,21±5,156 mg asam askorbat/g ekstrak dan total fenol tertinggi 2,44±0,354 mg/g. Kandungan senyawa bioaktif pada ekstrak bunga yaitu fenol, saponin, flavonoid, tanin dan triterpenoid., Rhizophora mucronata is one type of mangrove plant that grows in Indonesia. Bioactive compound in R. mucronata has potential to use against reactive species. The purpose of this study were to determine bioactive compound and antioxidant activity in leaves, flowers and fruits of R. mucronata. This study includes characterization of fresh and dried leaves, flowers and fruits and determining phytochemical content, total phenolic and antioxidant activity from extract of R. mucronata. Flowers exctract has the highest antioxidant activity 55.21±5.156 mg ascorbic acid/g extract and highest phenolic total 2.44±0.354 mg/g. Flowers extracts has bioactive compound content such as phenol, saponin, flavonoid, tanin and triterpenoid.
Keyword: antioksidan, Rhizophora mucronata, total fenol

Judul: Potensi Ekstrak Rhizophora sp. sebagai Inhibitor Tirosinase
Abstrak: Rhizophora sp. is one of plant type that has benefit as medicinal plants, for example, as whitening agent. The purpose of this study is to discover the parts and species of Rhizophora sp. which have best tyrosinase inhibitory activity. Leaves, stems, and roots of R. mucronata and R. stylosa were extracted with methanol and were tested their activities in order to obtain the best tyrosinase inhibitory activity. Based on the results, extracts of leaves, stems, and roots of R. mucronata from Tritih, Cilacap; Gebang, Cirebon; Eretan Kulon, Indramayu; Ujung Negoro Beach, Batang; Sigundu Beach, Batang; and Kapuk Beach, Jakarta were not potencial as tyrosinase inhibitor. Tyrosinase inhibitor activity from roots of R. mucronata from Samboja, East Kalimantan was higher than from its leaves and stems, especially for monophenolase with IC50 15.34 μg/ml. In perponderonce with, tyrosinase inhibitor activity from stems of R. stylosa from Samboja, East Kalimantan was also higher compared with stems of R. mucronata with IC50 38.02 μg/ml.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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