Judul: Isolation of Endophytic Actinomycetes in Medicinal Plants and Their Potency as an Antidiabetes Based on α-glucosidase Activity.
Abstrak: Endophytic actimomycetes lives in plant tissues without causing a negative impact on plant. Several medicinal endophytic microbes are able to produce the same bioactive compounds as produced by the host. Inhibition of α-glucosidase is one of antidiabetes mechanism. The potency of endophytic actinomycetes from medicinal plant as α-glucosidase inhibitor needs to be elucidated. Temulawak (Curcuma xanthorrhiza), ciplukan (Physalis minima) and brotowali (Tinospora crispa) were surface sterilized and crushed, then plated on humic acid vitamin B. Actinomycetes colonies were purified and produced on International Streptomyces Project No. 4 followed by α-glucosidase assay. Crude extracts with the highest inhibition of α-glucosidase were freeze dried, then diluted at 0.07%, 0.1%, 0.3%, 0.5% (w/v) with dimethylsulfoxide and assayed. Commercial inhibitor, acarbose (Glucobay; Bayer) were used as a comparation. Fourty six isolates were classified into 29 isolates Gram positive and 17 isolates Gram negative. Fifteen isolates were actinomycetes which 11 isolates obtained from brotowali stem, and 4 isolates from temulawak rhizome. The highest inhibition (61.27%) were shown by Cx-10.1 temulawak isolate at 0.07% (w/v) concentration compared with Glucobay 0.1% (w/v) which was only 39.70%. At 0.07% (b/v) concentration, Tc-2.1 from brotowali produce low activity (24.16%). Endophytic Cx-10.1 isolate could be potential to produce higher activity of α-glucosidase inhibitor compared with Glucobay.
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Judul: Aktivitas Inhibisi Enzim α-Glukosidase dan Sitotoksisitas Ekstrak Kurkuminoid Rimpang Temulawak dari Berbagai Aksesi (In Vitro)
Abstrak: Temulawak (Curcuma xanthorriza Roxb.) is one of the Zingiberaceae family medicinal plants that grow in Indonesia. Temulawak rhizome contains curcuminoid which useful as an antidiabetic. This research aims to get temulawak accession with high capability of the inhibition activity of the α-glukosidase enzyme and it’s potential as a compound that toxic to shrimp’s larval Artemia salina Leach. Antidiabetic activity has been measured by formation of p-nitrophenol from enzymatc reaction of nitrophenil-α-D-glucopyranose (p-NPG) which is catalyze by α-glucosidase enzyme. The formation of p-nitrophenol was measured by spectrophotometer at λ=410 nm. The results of curcuminoid content and bioactivity assay (α-glukosidase enzyme inhibition and cytotoxicity) showed that the best accession of temulawak is Wonogiri’s accession. The value of curcuminoid content, IC50, LC50, from Wonogiri’s accession of temulawak rhizome extract, respectively for 85.19±4.64 mg/g, 333±22.52 μg/mL, and 82.78±7.70 μg/mL. Wonogiri’s accesion has the potential to be further researched and developed as a new variety.
Keyword: Bogor Agricultural University (IPB), cytotoxicity, curcuminoids, antidiabetic, Curcuma xanthooriza

Judul: Transisi Fasa Materi Hadronik ke Materi Kuark pada Inti Bintang Neutron.
Abstrak: Bintang neutron terdiri dari beberapa lapisan yang disusun oleh materi nuklir yang berbeda dengan kerapatan yang semakin tinggi ketika mendekati pusat bintang. Inti luar bintang neutron disusun oleh materi hadronik (nukleon, lepton, dan hyperon), sedangkan inti dalam bintang neutron disusun oleh kuark-kuark bebas (up, down, strange) yang saling berinteraksi. Tujuan penelitian ini adalah mempelajari bagaimana transisi dari inti luar ke inti dalam bintang neutron dengan menggunakan pendekatan RMF (Relativistic Mean Field) untuk materi hadronik dan CIDDM (Confined Isospin Density Dependent Mass) untuk materi kuark. Tekanan transisi diperoleh ketika potensial kimia barion materi hadronik dan materi kuark bernilai sama. Nilai tekanan transisi dengan parameter SU6-TM1 sekitar 87 MeV/fm3 dan diperoleh massa maksimum bintang neutron yaitu 1.92M dengan jari-jari sekitar 8.62 km. Nilai tekanan transisi dengan parameter SU6-G2 sekitar 53 MeV/fm3 dan massa maksimum bintang neutron yaitu 1.88M dengan jari-jari sekitar 8.16 km. Jenis transisi fasa adalah orde satu ditandai dengan diskontinuitas dalam kerapatan energi (adanya mixed phase). Parameter-parameter pada model nuklir yang digunakan menyebabkan perbedaan kekakuan persamaan keadaan (EOS) dari materi hadronik dan materi kuark sehingga nilai tekanan transisi dari fasa hadronik ke fasa kuark juga berbeda.
Keyword: bintang neutron, persamaan keadaan, transisi fasa