Judul: Trypsin Inhibitory Activity by Wungu Leaf Extract (Graptophyllum pictum (L.) Griff.) In Vitro
Abstrak: Tanaman wungu (Graptophyllum pictum (L.) Griff.) termasuk salah satu tanaman obat tradisional Indonesia. Daun dari tanaman wungu memiliki metabolit sekunder yang berpotensi sebagai anti obesitas dengan menginhibisi enzim tripsin sehingga efek yang dihasilkan akan lebih optimal. Penelitian ini bertujuan menentukan aktivitas penghambatan enzim tripsin oleh ekstrak daun wungu sebagai anti obesitas. Penelitian ini dilakukan dengan uji kadar air dengan metode gravimetri menghasilkan kadar air sebesar 9.38±0.22% dan kadar abu sebesar 12.54 ± 2.48%. Ekstraksi dilakukan dengan metode maserasi menggunakan pelarut air, etanol, dan etil asetat dengan nilai rendemen berturut-turut sebesar 0.96 ± 0.37%, 0.65 ± 0.26%, dan 0.03 ± 0.02%. Uji aktivitas protein enzim tripsin menggunakan ekstrak dengan konsentrasi 0, 500, 1000, dan 2000 ppm menunjukkan nilai IC50 sebesar 2846.36 untuk ektrak air, 2822.25 untuk ekstrak etanol, dan 1915.25 untuk ekstrak etil asetat. Simpulan penelitian ini yaitu ekstrak daun wungu memiliki potensi untuk dikembangkan sebagai salah satu bahan aktif anti obesitas., The wungu plant (Graptophyllum pictum (L.) Griff.) is one of Indonesia's traditional medicinal plants. The leaves of the Wungu plant have secondary metabolites that have the potential to act as anti-obesity by inhibiting the trypsin, so that the resulting effect will be more optimal. This study aims to determine the inhibitory activity of the trypsin by Wungu leaf extract as an anti-obesity agent. This research was carried out by testing the water content using the gravimetric method to produce a moisture content of 9.38 ± 0.22% and an ash content of 12.54 ± 2.48%. Extraction was carried out by maceration method using water, ethanol and ethyl acetate solvents with yield values of 2.87%, 1.94% and 0.10% respectively. Trypsin protein enzyme activity test using extracts with concentrations of 0, 500, 1000, and 2000 ppm showed IC50 values of 2846.36 for the water extract, 2822.25 for the ethanol extract, and 1915.25 for the ethyl acetate extract. The conclusion of this study is that Wungu leaf extract has the potential to be developed as an anti-obesity active ingredient.
Keyword: anti-obesity, trypsin, wungu leaves

Judul: Aktivitas Penghambatan Kolagenase Ekstrak Daun Wungu  (Graptophyllum pictum (L.) Griff ) sebagai Anti Penuaan In Vitro
Abstrak: Tanaman wungu (Graptophyllum pictum (L.) Griff) merupakan salah satu tanaman obat tradisional masyarakat Indonesia. Tanaman daun wungu mengandung metabolit sekunder yang berpotensi dapat mencegah terjadinya proses penuaan dengan menghambat aktivitas kolagenase (Matriks metalloproteinase-1, MMP-1). Penelitian ini bertujuan menentukan aktivitas penghambatan enzim MMP-1 oleh ekstrak daun wungu sebagai anti penuaan. Penelitian dilakukan dengan uji kadar air dan uji kadar air metode gravimetri dan didapat nilai kadar air sebesar 9.38±0.22% dan kadar abu sebesar 12.54±2.48%. Ekstraksi dilakukan secara maserasi menggunakan pelarut etil asetat dan etanol, dan perebusan menggunakan pelarut air dengan nilai rendemen berturut-turut sebesar 21.31%, 13.35%, 4.84%. Uji aktivitas penghambatan kolagenase menggunakan ekstrak dengan konsentrasi 250 ppm menunjukkan nilai inhibisi sebesar 64.52±5.59% untuk ekstrak etil asetat, 46.77±14.52 untuk ekstrak etanol, dan 91.51±1.48% untuk ekstrak air. Nilai inhibisi N-Isobutyl-N-(4-methoxyphenylsulfonyl)glycyl hydroxamic acid (NNGH) dan retinol sebagai kontrol adalah sebesar 61.29±9.68% dan 66.13±4.84%, Berdasarkan hasil tersebut ekstrak daun wungu berpotensi dikembangkan sebagai salah satu bahan aktif anti penuaan kulit., Wungu (Graptophyllum pictum (L.) Griff) is traditional medicinal plants in Indonesian that have the potential to prevent the aging process by inhibiting collagenase activity (Matrix metalloproteinase-1, MMP-1). This study aims to determine the inhibitory activity of the MMP-1 enzyme by wungu leaf extract as an anti-aging agent. The research start with water content test and a ash content test using the gravimetric method with a value of 9.38±0.22% and 12.54±2.48%. Extraction by maceration using ethyl acetate and ethanol, and boiling using water solvent with yield values of 21.31%, 13.35%, 4.84%, respectively. Collagenase inhibitory activity test using 250 ppm extract showed inhibition results of 64.52±5.59% for the ethyl acetate extract, the ethanol extract 46.77±14.52%, and the aqueous extract 91.51±1.48%. Inhibition values of N-Isobutyl-N-(4- methoxyphenylsulfonyl)glycyl hydroxamic acid (NNGH) and retinol as controls were 61.29±9.68% and 66.13±4.84%. Based on these results, wungu leaf extract has the potential to be developed as an anti-aging active ingredient.
Keyword: Anti Aging, Aging, Collagenase, MMP-1, Wungu Leaf

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: