Judul: Fraksi Polar Daun Jambu Biji (Psidium guajava) sebagai Antiretroviral terhadap Simian Retrovirus
Abstrak: Psidium guajava leaf extract contain active compound that is expected to block the activity of reverse transcriptase enzyme, so it is potential to inhibit retrovirus replication, such as simian retrovirus (SRV). This virus infect long-tailed macaques which has similarity to the acquired immunodeficiency syndrome in human. Therefore, the purpose of this study was to evaluate antiretroviral effect of P. guajava leaf fraction to cell culture infected with SRV. Real-time polymerase chain reaction was used to evaluate the antiretroviral effect. The result showed that simplicia of P. guajava contained secondary metabolites, namely flavonoids, saponins and steroids. Ethanol 50% extract inhibited SRV replication at 7.8 ppm without toxicity to A549 cells. Further fractionation with mixed eluent of chloroform and methanol (7:3) yielded a fraction that inhibited SRV replication at 125 ppm. Based on infra-red spectra, the suspected functional group was flavonols.
Keyword: real-time polymerase chain reaction, reverse transcriptase inhibitor, Psidium guajava leaves

Judul: Kuersetin dari Ekstrak Daun Jambu Biji Merah (Psidium guajava) dan Kinerjanya sebagai Penghambat Proliferasi Sel Kanker
Abstrak: Red guava leaf (Psidium guajava) extract has been known to inhibit cancer cell proliferation. However, further studies on the activity of flavonoids in red guava leaves as an anticancer agent has not been done. This study aims to test the inhibitory activity on Raji cells (ATCC CCL-86) by quercetin in guava leaves. Methanol crude extract was fractionated using vacuum liquid chromatography and column chromatography techniques to obtain fraction rich of quercetin. Fractionation of the crude methanol extract gave a fraction which shows a spot at Rf 0.675, which is similar to that of standard quercetin. Identification of quercetin fraction with liquid chromatography-mass spectrometry showed the fragment ion spectra of the quercetin (m/z 150, 151, 152). The quercetin fraction has been tested for its activity toward Raji cells and Vero cells. The quercetin fraction inhibited proliferation of Raji cells by 60%, at a concentration of 100 mg mL-1, but only inhibits the proliferation of Vero cells by 10%. This result indicates the quercetin fraction of guava leaf is able to inhibit the proliferation of Raji cells, but not toward Vero cells.
Keyword: quercetin, Psidium guajava, flavonoids, cancer cells proliferation

Judul: Penggunaan Metode Homotopi untuk Menyelesaikan Masalah Nilai Eigen pada Suatu Model Getaran
Abstrak: Most mathematical models of natural phenomena are nonlinear model. One of the nonlinear problems is a problem of vibration which can be considered as an eigen value problem. Here, the nonlinear factor appeared due to the external forces applied to the system. The vibration problem in this study, was solved using the homotopy method. The homotopy method is analytical approach in the nonlinear problems within the series form. The terms of the series were obtained based on a recursive formula in a high deformation. A convergent solution of the series dependent on both the homotopy parameter and the coefficient of nonlinear factors appeared in the model.
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