Judul: Aktivitas antihipertensi aktinomiset endofit asal tanaman pegagan dan belimbing wuluh
Abstrak: Endophytic actinomycetes lives in the plant tissue without causing a negative impact. Several medicinal associates with endophytic microbe which may produce similar bioactive compounds to their host plant. Inhibition of Angiotensin Converting Enzyme (ACE) is one of the effective antihypertension mechanism. The potency of endophytic actinomycetes from the medicinal plant used as ACE inhibitor needs to be elucidated. The research aimed to isolate endophytic actinomycetes from rhizome, stem, leaf of pegagan (Centella asiatica) and also from fruit of belimbing wuluh (Averrhoa bilimbi), and assess their capability to produce bioactive compound which can function as ACE inhibitor. The endophytic actinomycetes were isolated from surface sterilized plant parts, grounded and plated in Humic-acid Vitamin-B agar (HV) medium. The purified isolates were grown on International Streptomyces Project No.2 (ISP2) medium, and the crude extract which consisted of extracellular bioactive compound, was used for in vitro assay of ACE inhibitor activity. Twelve isolates of endophytic actinomycetes were successfully isolated from pegagan leaves (three isolates) and belimbing wuluh fruits (nine isolates). The data showed that nine isolates (AEP-1, AEP-2, AEP-3, AEB-1, AEB-3, AEB-5, AEB-6, AEB-7, and AEB-8), had various ACE inhibitor activities, and belonged to Streptomyces spp.. Three other isolates (AEB-2, AEB-4, and AEB-9) belonged to non-Streptomyces, and also showed various ACE inhibitor activities,. Meanwhile, free endophytic microbes of tissue culture seedling of pegagan did not show any ACE inhibitor activity. The AEP-1 isolated from pegagan had the highest percentage (279.2%) followed by AEB-5 isolated from belimbing wuluh (222,92%) of ACE inhibitor activity, exceeding the ACE inhibition activity of captopril (0.01 mg/mL) which was 61.5% and captopril (0.02 mg/mL) was 66.7%. The data indicate that endophytic actinomycetes isolated from leaf of pegagan and fruit of belimbing wuluh capable of producing ACE inhibitory compound.
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Judul: Inhibition of Pegagan (Centellaasiatica) and Tempuyung (Sonchusarvensis) Extracts towards Angiotensin Converting Enzyme (ACE) Activity
Abstrak: Pegagan dan tempuyung merupakan tanaman obat yang berpotensi sebagai antihipertensi. Ekstrak tanaman ini diteliti daya inhibisinya terhadap aktivitas enzim pengubah angiotensin I (ACE) secara in vitro. Penelitian dilakukan pada kondisi optimum menggunakan ekstrak tunggal dengan konsentrasi 50, 100, dan 150 ppm serta ekstrak gabungan dengan komposisi tertentu. Hasilnya dibandingkan dengan kaptopril sebagai kontrol positif. Uji inhibisi ACE dengan ekstrak tunggal pegagan dan tempuyung 50 ppm menghasilkan daya inhibisi paling tinggi yaitu 54% dan 31%. Esktrak gabungan pegagan tempuyung menghasilkan daya inhibisi yang lebih rendah dibandingkan ekstrak tunggal pegagan, yaitu 45% berbanding 54%. Kaptopril memiliki daya inhibisi yang paling tinggi dibandingkan ekstrak tunggal maupun gabungan, yaitu 88%. Kata Kunci: Inhibisi ACE, kaptopril, pegagan, tempuyung, Pegagan and tempuyung are medicinal plants potential as antihypertension. Extracts of these plants were investigated towards angiotensin I converting enzyme (ACE) inhibition activity in vitro. The study was conducted at the optimum condition by using 50,100 and 150 ppm of single extract concentration, and combined extracts with specific compositions. The results were compared with captopril as positive control. Inhibition test of ACE with single extracts showed that 50 ppm pegagan and tempuyung have the highest inhibition of 54% and 31%. The combined extracts of pegagan and tempuyung showed lower inhibition than single pegagan extract, i.e. 45% versus 54%. Captopril still indicated the highest inhibition (88%) as compared to single or combined extracts. Key words: ACE inhibition, captopril, pegagan, tempuyung
Keyword: Inhibisi ACE, kaptopril, pegagan, tempuyung

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