Judul: Isolation and cytotoxicity of theen leaves (ficus carica linn.) flavonoid extract
Abstrak: Penggunaan daun tin (Ficus carica) sebagai obat mulai dikembangkan di Indonesia sejak tahun 2011. Studi mengenai potensi bioaktif tanaman tin telah banyak dilakukan di dunia, tetapi belum banyak dilakukan di Indonesia. Penelitian ini dilakukan untuk menentukan sitotoksisitas ekstrak flavonoid daun tin berdasarkan metode uji letalitas larva udang (BSLT) dan toksisitas embrio ikan zebra (ZFET). Hasil penelitian menunjukkan rendemen ekstrak flavonoid pada sampel sebesar 2.36% dengan nilai LC50 sebesar 422 ppm dengan metode BSLT dan 181 ppm dengan metode ZFET. Hasil ini lebih tinggi dibandingkan dengan ekstrak kasar metanol. Uji kualitatif terhadap ekstrak menunjukkan kandungan flavonoid berupa flavon dan flavonol dalam fraksi etil asetat dari ekstrak metanol. Pemberian ekstrak kasar flavonoid daun tin pada embrio ikan zebra menimbulkan abnormalitas mayor pada sirkulasi darah. Berdasarkan hasil ini ekstrak kasar flavonoid daun tin cukup toksik dan efek toksiknya diduga dominan pada sistem sirkulasi darah makhluk hidup., Theen leaves have been used as traditional medicine in Indonesia since 2011. The bioactivity potential of the leaves has been acknowledged in international research, but lack of information in Indonesia so far. This study aims to examine the cytotoxicity of theen leaves flavonoid extract against brine shrimp (Artemia salina) and zebrafish (Danio rerio) embryo. The result showed that flavonoid in the sample was 2.36% and the 50% lethal concentrations (LC50) were 422 and 181 ppm against brine shrimp and zebrafish embryo, respectively. The qualitative assay for flavonoid class indicated the presence of flavones and flavonols class. The zebrafish embryo test indicated a major malformation on blood circulation. Based on these facts, the flavonoid extract is toxic and has effect to blood circulation of living organism. Key words: brine shrimp lethality test, flavonoid, theen leaves, zebra fish embryo toxicity.
Keyword: daun tin, flavonoid, toksisitas embrio ikan zebra, uji letalitas larva udang

Judul: Uji Toksisitas Ekstrak Etanol Rimpang Temu Putih terhadap Larva Udang dan Embrio Ikan Zebra
Abstrak: Curcuma zedoaria, known as temu putih, is commonly used as traditional medicine in Indonesia. The toxicity of this herb needs to be studied to improve its application. This research aims to evaluate the toxicity of the crude ethanol extract of temu putih rhizome against brine shrimp (Artemia salina) larvae and zebrafish (Danio rerio) embryos and to analyze the suspected active compounds contained in the extract. The crude ethanol extract showed 50% lethal concentration value (LC50) at 588 ppm against brine shrimp larvae and 215 ppm against zebrafish embryos. In zebrafish embryos, exposure of the crude ethanol extract has caused major malformation in development of head, namely brain and eyes organs. Based on the gas chromatography-mass spectrometry analysis, the suspected active compound that play a role in the toxicity are epicurzerenone, curzerene, and curzerenone, which 2,4,6-trimethylacetophenone as the predominant compound.
Keyword: Bogor Agricultural University (IPB), LC50, Danio rerio, Curcuma zedoaria, Artemia salina

Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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