Judul: Pengaruh Perebusan Terhadap Aktivitas Biologis Dan Kandungan Fenolik Buah Takokak (Solanum Torvum Swartz)
Abstrak: Buah takokak (Solanum torvum Swartz.) biasa dikonsumsi masyarakat Indonesia sebagai pangan pendamping. Selain itu, buah takokak sering pula digunakan sebagai obat tradisional, salah satunya sebagai obat diabetes mellitus. Penelitian ini bertujuan untuk mengetahui total fenol, aktivitas antioksidan, dan aktivitas alfa glukosidase inhibitor dari ekstrak metanol, fraksi air, butanol, kloroform, dan n-heksan buah takokak segar dan rebus. Hasil penelitian menunjukkan fraksi air buah takokak segar memiliki kandungan total fenol tertinggi yaitu sebesar 107.00 μg GAE/mg ekstrak. Sementara fraksi buah takokak rebus dengan kandungan total fenol tertinggi adalah fraksi butanol, yaitu sebesar 129.08 μg GAE/mg ekstrak. Perebusan meningkatkan kandungan total fenol secara signifikan pada taraf signifikansi 5% kecuali pada fraksi air. Uji aktivitas antioksidan DPPH menunjukkan fraksi dengan aktivitas antioksidan tertinggi adalah fraksi heksan takokak segar dan fraksi air takokak rebus dengan nilai IC50 masing-masing sebesar 82.05 mg ekstrak/mL dan 24.58 mg ekstrak/mL. Perebusan meningkatkan aktivitas antioksidan secara signifikan pada taraf signifikansi 5%. Uji penghambatan alfa glukosidase menunjukkan fraksi butanol dan kloroform buah takokak segar memiliki penghambatan alpha glukosidase masing-masing mencapai 56.40% dan 72.61%. Sementara fraksi takokak rebus yang memiliki aktivitas penghambatan adalah fraksi butanol sebesar 80.01%. Aktivitas penghambatan alfa glukosidase pada buah takokak rebus berbeda nyata pada taraf signifikansi 5% kecuali pada fraksi n-heksan. Uji statistik Pearson correlation pada ketiga data menunjukkan korelasi yang cenderung lemah antara kandungan total fenol dengan baik aktivitas antioksidan aktivitas maupun penghambatan alfa glukosidase pada sampel segar dan rebus.
Keyword: buah takokak, alfa glukosidase inhibitor, antioksidan, total fenol, diabetes mellitus

Judul: Aktivitas Antioksidan Ekstrak Buah Takokak (Solanum torvum Swartz.)
Abstrak: Turkey berry fruit (Solanum torvum Swartz.) is one of indigenous fruit vegetables that widely used in traditional medicine. Because, it has some functional properties such as antioxidant, antibacterial, antifungal, and antiviral. The functional properties come from the activity of some phytochemicals compound that Turkey berry fruit contents, such as phenolics and non phenolics. This research was designed to identify the chemical content of Turkey berry fruit, change content, and antioxidant activity of crushed form. The research method consisted of treatment phase of fresh Turkey berry fruit through the destruction process and extraction phase of Turkey berry fruit powder with organic solvents (methanol, etil acetat, and hexane). The results showed that methanol extract of both whole and crushed Turkey berry fruit, contains alkaloids, flavons, tannins, and saponins. The etil acetat and hexan extracts of both whole and crushed form, contains alkaloids, flavons, terpenoids, and saponins. Thus, the presence of phenolic compounds in Turkey berry fruit can be affected by Phenylalanin Ammonia Lyase (PAL) activity, but not always influenced by the total anthocyanin. In addition, the antioxidant activity (DPPH assay) between whole and crushed Turkey berry fruit extracts is not significantly different (p>0.05) by t-test. It was demonstrated that the destruction process has a little affecting to the presence of phenolic compounds that act as antioxidants, such as anthocyanin. However, the antioxidant activity of extracts is not always determined from total phenolic, but depending on the ability of -OH group to donate H atoms and to bind with free radicals rapidly. The antioxidant activity of Turkey berry fruit extract was slightly be affected by ascorbic acid (vitamin C) compound.
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Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
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