Judul: Profil Fitokimia dan Toksisitas Ekstrak Rimpang Temu Ireng (Curcuma aeruginosa R.) pada Larva Udang
Abstrak: Curcuma aeruginosa berpotensi sebagai tanaman herbal karena mengandung metabolit sekunder. Penelitian ini bertujuan menentukan profil fitokimia dan toksisitas larva udang pada ekstrak rimpang induk, anak, dan cucu temu ireng. Ekstrak ketiga rimpang temu ireng didapatkan dengan teknik maserasi menggunakan pelarut etanol 96%, etanol 70%, dan akuades. Selanjutnya, ekstrak digunakan dalam analisis komponen fitokimia dan aktivitas toksisitas terhadap larva udang Artemia salina L. Kadar air ketiga simplisia berada dibawah 10%. Rendemen tertinggi dimiliki oleh ekstrak akuades, sedangkan ekstrak etanol 96% memiliki rendemen terendah. Semua ekstrak mengandung tanin, saponin (kecuali ekstrak induk dalam etanol 96%), dan triterpenoid. Komponen fitokimia pada tanaman herbal dapat bersifat toksik pada konsentrasi tertentu. Uji BSLT (Brine Shrimp Lethality Test) digunakan untuk mengetahui konsentrasi ekstrak yang mampu membunuh 50% populasi (LC50). Uji toksisitas untuk farmakologi awal menunjukkan ekstrak induk dalam etanol 96% berpotensi sebagai obat herbal karena bersifat sangat toksik dengan LC50 sebesar 90.40 µgmL-1.
Keyword: Curcuma aeruginosa, Phytochemical, Toxicity, Type of Rhizome, Biokimia, Jenis rimpang, Pebuatan ekstrak kasar rimpang, Shrimp

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.
Keyword: