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 temu lawak dan meniran serta penentuan sidik jari kromatografinya
Abstrak: Anti-acne activity of extracts from C. xanthorriza and P. niruri has been analyzed through antioxidant and antibacterial activity assays. Extraction process was conducted by two different maceration methods, Indonesian and traditional chinese medicine (TCM) with ethanol 96% as the solvent. Formula 6 (2/3 C. xanthorriza:1/6 P. niruri:1/6 starch) was the most active anti-acne formula with IC50 of antioxidant values of 93.17 ppm, the minimum inhibitory concentration against Staphylococcus epidermidis was 0.25 mg/mL, and the minimum bactericidal concentration was 0.50 mg/mL. Moreover, TCM maceration was better than the Indonesian method in terms of antioxidant and antibacterial activities. Fingerprint analysis of formula was undertaken using thin layer chromatography. The optimum mobile phase was chloroform that gave 9 bands. Further, the (HPLC) analysis with C18 as column and gradient of acetonitrile and water as the mobile phase showed that the peak area of phyllanthin and curcumin increased when the standard compounds were added into the sample.
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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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