Judul: Fraksi aktif ekstrak daun Sansevieria trifasciata Prain sebagai penghambat pertumbuhan sel lestari HeLa
Abstrak: Sansevieria trifasciata Prain is an ornamental plant which is also useful as a source of antibacterial and antioxidant agent. Studies of S. trifasciata Prain as anticancer have not been reported. Therefore, the objective of this study is to isolate bioactive compounds of S. trifasciata Prain leaves that shows in vitro proliferation inhibition of HeLa cell lines. The sample was macerated in 96% methanol and concentrated using a rotary evaporator. The crude extract was fractionated using chromatography column with silica gel as the stationary phase and gradient chloroform-ethyl acetate as the mobile phase. Qualitative phytochemical and inhibition activity using MTT assay (3- (4,5-dimethylthiazol- 2-yl)-diphenyltetrazolium-2,5-bromide) were performed on the crude extract and its fractions at concentrations between 200 and 1000 ppm. The crude extract contained flavonoids, alkaloids, and steroids, but the crude extract could not inhibit proliferation of HeLa cell lines. The chromatography resulted 10 fractions, however, there was only one fraction with the highest proliferation inhibition was 87.52% at concentration of 10000 ppm that. This fraction contained flavonoids and alkaloids.
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Judul: Aktivitas antibakteri fraksi aktif daun lidah mertua (Sansevieria trifasciata Prain)
Abstrak: Sansevieria trifasciata Prain is an indigenous plant of South Africa and indicated has an antibacterial activity. The purpose of this study is to evaluate the potential of this speciesas antibacterial to inhibit the activity of Staphylococcus aureus and Escherichia coli using disc diffusion method. Some leaves were extracted using maceration method. The result indicated that crude extract at concentration 1250, 2500, 5000, and 10000 ppm showed no activity against the test bacterial. Steroids, flavonoids, and alkaloids were found in the crude extract. The crude extract was fractionated using column chromatography. Ethyl acetate and chloroform were used as eluent with the best ratio (6:1). The fractionation yield 10 fractions. The fraction were test at concentration 10000, 20000, and 40000 ppm. The antibacterial assay showed there was only 1 fraction active against Gram-positive (S. aureus).
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Judul: Dynamic New Keynesian Model for Unemployment and Inflation Rate.
Abstrak: This paper deals with a scientific analysis of the equilibrium level of hiring, employment and unemployment. The basic model being used is a standard new Keynesian model, which states that utility function depends on consumptions and working hours. Utility maximization refers to a standard labour supply equation, with the marginal cost’s dynamics on new Keynesian model simply reflects movements in real wages and productivity. Furthermore, trade-off between output and inflation stabilization can be considered using the new Keynesian Phillips curve. Dynamic general equilibrium model is a model that can be used to study interactions between market imperfections and nominal rigidities, which is capable of overcoming the main shortcoming of the standard new Keynesian model. In the general equilibrium model there are three groups of the economy agents, namely households, firms and monetary authority. The results of this research science that bargaining processes between firms and workers will yield optimal wage. Increase in labour will cause wages to fall, but the unemployment rate can be reduced. An increase in the firm’s monopoly power will shift the labour demand curve downward, which will reduce the number of workers that firm is willing to hire for any given bargained wage.
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