Judul: Fraksi Aktif Antioksidan dari Ekstrak Kulit Kayu Sungkai (Peronema canescens Jack.)
Abstrak: Sungkai (Peronema canescens Jack.) bark extract is potentially containing extractive materials with antioxidant properties. The objective of this research was to fractionate 70% of ethanol extract of sungkai bark, hydrolize the n-hexane residue, determine fraction content and antioxidant activity using in vitro testing, and analyze chemical compounds found in three of the most active fraction. Fractionation was conducted using solvent-solvent extraction with n-hexane and ethyl acetate. Antioxidant activity was examined using 1,1-difenil-2-pikrilhidrazil (DPPH) method. The chemical components of three most active fraction were analyzed by gas chromatography mass spectrometry (GC-MS). Extract value of n-hexane fraction was the highest levels.. The three most active fractions with antioxidant properties are non-hydrolized etil acetate, n-hexane, and hydrolized ethyl acetate (IC50 43.67, 44.55, and 53.34 μg/mL). Phenolic compound identification shows several dominant compounds: quinic acid, guaiacol, hydroquinone, isovanillic acid, genkwanin, catechol, and benzoic acid. Those compounds are categorized as phenol and own strong antioxidant activity
Keyword: phenol, sungkai, antioxidant

Judul: Kandungan Fitokimia dan Penghambatan Radikal Bebas DPPH Ekstrak Kulit Kayu Surian (Toona sinensis).
Abstrak: Ekstrak kulit kayu surian (Toona sinensis) diketahui berpotensi sebagai antioksidan alami seperti flavonoid dan fenolik. Tujuan penelitian ini adalah mengetahui kandungan fitokimia dan menguji aktivitas antioksidan ekstrak kulit kayu dari tumbuhan surian yang berumur 30 tahun. Metode yang digunakan yaitu ekstraksi (maserasi dan refluks), penentuan fitokimia, dan pengujian antioksidan (DPPH). Maserasi menggunakan pelarut etanol dengan konsentrasi 30%, 70%, dan 96%. Metode ekstraksi refluks menggunakan pelarut air dengan suhu 80 oC selama 2 jam. Hasil penelitian menunjukkan kandungan fitokimia yang terdapat pada ekstrak kulit kayu surian adalah saponin, tanin, triterpenoid, flavonoid, dan fenolik. Pengujian aktivitas antioksidan menggunakan bahan uji DPPH (2,2-difenil-1- pikrilhidrazil) dilakukan untuk menentukan IC50. Nilai IC50 yang didapat pada standar asam askorbat, ekstrak pelarut air, ekstrak pelarut etanol 30%, etanol 70% dan etanol 96% berturut-turut adalah 4.609 μg/mL, 17.380 μg/mL, 19.8 μg/mL, 21.828 μg/mL, dan 21.821 μg/mL. Ekstrak pelarut air memiliki aktivitas penghambatan radikal DPPH tertinggi, diikuti pelarut etanol 30%, 96% dan 70%.
Keyword: antioksidan, DPPH, fitokimia, IC50, surian

Judul: Implementasi Space Time Composite (STC) Data Model Menggunakan Model Data Relasional
Abstrak: The data model is a concept that describes the data stored in the database and the relationship between the data to the user in logic. Development of data models is very important in the design of the database as the basis of the stage of database design to be made. This study aims to apply the concept of Space Time Composite (STC) on the Model Data storage vector data types that can store enough information and describes the process of drafting objects and objects spatiotemporal evolution over time. From the results of the test queries on the data model that have been created, queries in a system are acquired that can help display the information preparation of objects from time to time and know the history of the object polygon and arc that has undergone changes in topology.
Keyword: