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: Potensi ekstrak daun jambu biji merah (psidium guajava) dan daun sirsak (annona muricata) untuk menghambat proliferasi sel kanker raji
Abstrak: Daun jambu biji merah (Psidium guajava) mengandung senyawa kuersetin dan daun sirsak (Annona muricata) mengandung kaempferol. Kedua senyawa flavonoid tersebut memiliki potensi menghambat proliferasi sel kanker. Tujuan penelitian ini adalah mengevaluasi potensi fraksi ekstrak daun jambu biji merah (fraksi kaya-kuersetin) dan fraksi ekstrak daun sirsak (fraksi kaya-kaempferol) dalam menghambat proliferasi sel kanker Raji dengan metode ekstraksi maserasi. Ekstrak metanol didapatkan dengan memaserasi serbuk sampel setelah sampel dibebaskan dari senyawa nonpolar menggunakan n-heksana. Ekstrak dari setiap sampel dimurnikan menggunakan kromatografi cair vakum dan didapatkan 0.28% fraksi kaya-kuersetin, dan 2.00% fraksi kaya-kaempferol. Kadar aglikon kuersetin dan kaempferol berdasarkan kromatografi cair kinerja tinggi berturut-turut 1.27 dan 0.67 ppm. Kedua fraksi diuji efek penghambatannya terhadap sel Vero (sel normal) dan sel Raji (se kanker darah). Persen penghambatan kedua fraksi terhadap sel Vero sebesar 200 ppm. Hasil pada sel Raji menunjukkan rendahnya persen penghambtan kedua ekstrak, terutama fraksi kaya-kuersetin tidak menunjukkan penghambatan sel. Berdasarkan hasil tersebut disimpulkan bahwa fraksi kaya-kuersetin dan kaempferol tidak berpotensi dalam menghambat proliferasi sel kanker Raji. Kata kunci: antikanker, jambu biji merah, kaempferol, kuersetin, sirsak
Keyword: nticancer, guava, kaempferol, quercetin, soursop

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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