Judul: Antioxidant and Anticancer Activities of Spirulina platensis Against A549 Lung Cancer Cells In Vitro
Abstrak: Spirulina platensis merupakan mikroalga kelompok cyanobacteria yang mengandung komponen aktif yang berpotensi sebagai antikanker. Tujuan penelitian ini yaitu menentukan kadar total fenolik dan kapasitas antioksidan serta aktivitas sitotoksik ekstrak Spirulina platensis dalam menghambat pertumbuhan sel kanker paru A549. Tahapan penelitian ini yaitu ekstraksi komponen aktif spirulina menggunakan metode maserasi dengan pelarut etanol 70%, uji total fenolik menggunakan larutan standar asam galat, uji aktivitas antioksidan menggunakan metode DPPH dengan larutan standar asam askorbat dan aktivitas antikanker paru A549 diuji dengan metode MTT-Assay secara in vitro menggunakan sampel Spirulina platensis dari dua produsen yang berbeda. Kadar total fenolik produsen A sebesar 18,915 mg GAE/g dan produsen B sebesar 19,096 mg GAE/g. Kapasitas antioksidan pada produsen A sebesar 11,97 mg AAE/g dan produsen B sebesar 13,21 mg AAE/g. Persen inhibisi antikanker tertinggi dihasilkan pada konsentrasi 100 ppm, yaitu 20,6% untuk produsen A dan 28,3% untuk produsen B., Spirulina platensis is a microalgae group of cyanobacteria that contains active components that have potential as anticancer. The purpose of this study was to determine the total phenolic content and antioxidant capacity and cytotoxic activity of Spirulina platensis extract in inhibiting the growth of A549 lung cancer cells. The stages of this study were extraction of active components of spirulina using maceration method with 70% ethanol solvent, total phenolic test using gallic acid standard solution, antioxidant activity test using DPPH method with ascorbic acid standard solution and A549 lung anticancer activity tested with MTT-Assay method in vitro using Spirulina platensis samples from two different producers. The total phenolic content of producer A was 18.915 mg GAE/g and producer B was 19.096 mg GAE/g. Antioxidant capacity in producer A was 11.97 mg AAE/g and producer B was 13.21 mg AAE/g. The highest percent anticancer inhibition was produced at a concentration of 100 ppm, which was 20.6% for producer A and 28.3% for producer B.
Keyword: Antioksidan, Antikanker, sel kanker paru A549, Spirulina platensis

Judul: Antioxidant, Anticancer, and Total Flavonoid of Spirulina Extract (Spirulina platensis) in Cervical Cancer HeLa Cells
Abstrak: Kanker serviks merupakan kanker dengan kasus terbanyak keempat yang terjadi secara global. Alternatif obat kemoterapi dibutuhkan karena obat ini dapat menyerang sel normal tubuh. Spirulina memiliki potensi sebagai antikanker karena memiliki senyawa flavonoid yang juga bermanfaat sebagai antioksidan dalam tubuh. Penelitian ini bertujuan menentukan aktivitas antioksidan, antikanker, dan total flavonoid pada ekstrak etanol spirulina dari dua produsen yang berbeda. Spirulina diekstraksi dengan metode maserasi menggunakan pelarut etanol. Hasil ekstraksi diukur kadar total flavonoid, aktivitas antioksidan menggunakan Ferric-reducing Antioxidant Power (FRAP), dan aktivitas sitotoksik terhadap sel kanker serviks HeLa dengan metode Monotetrazolium (MTT). Hasil penelitian menunjukkan kadar total flavonoid tertinggi diperoleh oleh sampel produsen B sebesar 12,52 ± 0,23 mg QE/g DW. Aktivitas antioksidan tertinggi terdapat pada sampel produsen B sebesar 16,55 ± 0,1 µmol TE/g DW. Ekstrak etanol spirulina kedua produsen menunjukkan adanya inhibisi sel kanker serviks HeLa sebesar 34,68 ± 1,06% pada konsentrasi 200 ppm sampel produsen A, dan 33,85 ± 2,23% pada konsentrasi 50 ppm sampel produsen B namun lebih kecil dibandingkan dengan doksorubisin., Cervical cancer is the fourth most common cancer globally. Alternatives to chemotherapy drugs are needed because these drugs can attack the body's normal cells. Spirulina has potential as an anticancer by its flavonoid compounds that are also useful as antioxidants in the body. This study aims to determine the antioxidant activity, anticancer, and total flavonoids in ethanol extracts of spirulina from two different producers. Spirulina was extracted by maceration method using ethanol solvent. The extraction results were measured for total flavonoid content, antioxidant activity using Ferric-Reducing Antioxidant Power (FRAP), and cytotoxic activity against HeLa cervical cancer cells using Monotetrazolium (MTT) method. The results showed that the highest total flavonoid content was obtained by sample of producer B at 12.52 ± 0.23 mg QE/g DW. Highest antioxidant activity was found in sample of producer B at 16.55 ± 0.1 µmol TE/g DW. The ethanol extract of spirulina of both producers showed the inhibition of HeLa cervical cancer cells, 34.68 ± 1.06% at a concentration of 200 ppm for sample of producer A, and 33.85 ± 2.23% in 50 ppm for sample of producer B.
Keyword: Antikanker, Antioksidan, spirulina, Anticancer, Antioxidant, Sel HeLa, HeLa Cells

Judul: Pemodelan Nilai Tukar Rupiah terhadap Dollar Amerika Menggunakan Deret Waktu Hidden Markov Empat Waktu Sebelumnya
Abstrak: The exchange rate of Rupiah to US Dollar fluctuates according to time in a long period. An existing exchange rate might happen again in the future. Assume that the causes of the fluctuation are not observed directly and form a Markov chain, then the exchange rate of Rupiah to US Dollar can be modeled by the hidden Markov time series. In this research, the model used to describe the exchange rate of Rupiah to US Dollar is the four previous time in hidden Markov time series. This model assumes that the exchange rate of Rupiah to US Dollar depends on Markov chain explained by the cause of occurence and the four previous exchange rates of Rupiah to US Dollar. The model parameter is estimated by using the maximum likelihood method, while the estimation itself is calculated using the expectation maximization algorithm, which is implemented using Mathematica. After estimating the parameter, the exchange rate of Rupiah to US Dollar are calculated. The results are as follows. The symmetric mean absolute percentage error (SMAPE) is 2,1%, the maximum absolute error is 19,16%, the minimum absolute error is 0,0036%, and only 1,95% of the whole absolute percentage error that is bigger than 10%. These results show that the four previous time in hidden Markov time series can describe the exchange rate of Rupiah to US Dollar very well.
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