Judul: Mixture Formula Temulawak (Curcuma xanthorriza) and Meniran (Phyllanthus niruri) Extract as Antiacne.
Abstrak: Penelitian ini bertujuan menguji efektivitas campuran ekstrak temulawak (Curcuma xantorrizha) dan meniran (Phyllanthus niruri) sebagai antijerawat dibandingkan masing-masing ekstrak, terutama dilihat dari aktivitasnya sebagai antibakteri terhadap Staphyllococcus epidermidis dan antioksidan. Rimpang temulawak dan meniran diekstraksi dengan etanol 96%. Selanjutnya ekstrak tersebut dibuat formula campurannya berdasarkan rancangan simplex centroid. Kesepuluh formula yang diperoleh diuji aktivitasnya sebagai antioksidan dan antibakteri. Formula 5 (½ temulawak dan ½ meniran) merupakan formula teraktif sebagai antijerawat dengan nilai IC50 untuk antioksidan sebesar 9.47 ppm, konsentrasi hambat minimum (KHM) untuk S.epidermidis sebesar 0.25 mg/mL, dan konsentrasi bunuh minimum (KBM) sebesar 1.00 mg/mL. Setelah dianalisis penciri dengan kromatografi lapis tipis (KLT) dan kromatografi cair kinerja tinggi (KCKT), diketahui bahwa dalam formula 5 terdapat senyawa xantorizol, filantin, dan hipofilantin.
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Judul: Aktivitas antijerawat formula campuran meniran dan temu lawak serta aktivitas inhibisinya terhadap katalase Staphylococcus aureus
Abstrak: Acne is an inflammation of skin caused by Staphylococcus aureus, S. epidermidis, and Propionibacterium acnes bacteria. Antiacne activity of temu lawak and meniran has been analyzed through antibacterial activities against S. aureus and S. epidermidis and inhibition of S. aureus catalase activity. Temu lawak and meniran were extracted by using maceration technique in 96% ethanol with two different maceration methods, Indonesian and traditional chinese medicine. S. aureus and S. epidermidis were successfully isolated. The growth of S. aureus was inhibited by temu lawak extract with minimum bactericidal concentration (MBC) 150 ppm and inhibition zone index 0.38. The growth of S. epidermidis was inhibited by mixture of temu lawak 2/3 and meniran 1/6 with MBC 300 ppm and inhibition zone index 0.40. Thin layer chromatography profile of both extracts showed curcuminoid band. Catalase enzyme was successfully isolated from S. aureus. Mixture of temulawak 2/3 and meniran 1/6 gave the best catalase inhibition activity, 6.88% in 500 ppm formula concentration.
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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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