Judul: Aktivitas Antioksidan Hasil Fermentasi Media Padat Berbasis Gandarusa (Justicia gendarussa Burm. f.) oleh Aspergillus oryzae
Abstrak: Gandarusa menghasilkan metabolit sekunder yang memiliki potensi sebagai senyawa antioksidan. Penelitian ini bertujuan menentukan aktivitas antioksidan serta menentukan pelarut terbaik untuk mengekstraksi hasil fermentasi media padat berbasis kedelai dan gandarusa oleh Aspergillus oryzae. Kadar total fenolik dan flavonoid tertinggi diperoleh pada ekstrak etil asetat fermentasi campuran media kedelai dan gandarusa (1:1) serta gandarusa (16,668 mg GAE/g ekstrak dan 21,822 mg QE/g ekstrak). Aktivitas antioksidan DPPH dan ABTS tertinggi diperoleh pada ekstrak metanol fermentasi gandarusa dan campuran kedelai dan gandarusa (1:1) (4,964 mg TE/g ekstrak dan 63,35 mg TE/g ekstrak). Aktivitas antioksidan FRAP tertinggi diperoleh pada ekstrak etil asetat gandarusa tanpa fermentasi dengan nilai 106,004 mg TE/g ekstrak. Kadar total fenolik dan flavonoid menunjukkan korelasi positif dengan aktivitas antioksidan FRAP dan ABTS namun tidak berkorelasi dengan aktivitas antioksidan DPPH. Pelarut terbaik untuk mengekstraksi hasil fermentasi media padat berbasis kedelai dan gandarusa yaitu metanol., Gandarusa produce many secondary metabolites that have potential as antioxidant. This research aims to measured the activity of antioxidant and determining the best solvent to extract soybean and gandarusa-based solid media fermentation by Aspergillus oryzae. The highest phenolic and flavonoid content was obtained by ethyl acetate extract of fermented soybean-gandarusa (1:1) and gandarusa, respectively (16,668 mg GAE/g extract, 21,822 mg QE/g extract). The highest antioxidant activity of DPPH and ABTS methods was obtained by methanol extract of fermented gandarusa and soybean-gandarusa (1:1), respectively (4,964 mg TE/g extract, 63,35 mg TE/g extract). The highest activity antioxidant of FRAP method was found in ethyl acetat extract of non-fermented gandarusa (106,004 mg TE/g extract). Total phenolic and flavonoid content had a strong positive and significant correlation with antioxidant activity of FRAP and ABTS methods, while there is no significant correlation with antioxidant activity of DPPH method. The best solvent to extract secondary metabolite of fermented soybean and gendarussa-based solid media is methanol.
Keyword: antioxidant, flavonoid, gandarusa, phenolic, solid-state fermentation

Judul: Kandungan Fenolik dan Aktivitas Antioksidan Ekstrak Daun Gandarusa Hasil Optimasi Pelarut dengan Metode Sonikasi
Abstrak: Gandarusa (Justicia gendarussa Burm. f.) merupakan tanaman obat yang memiliki senyawa antioksidan untuk menangkal radikal bebas karena adanya kandungan metabolit sekunder seperti senyawa fenolik. Kandungan fenolik yang terekstrak serta nilai aktivitas antioksidan dapat dipengaruhi oleh pemakaian pelarut ekstraksi. Penelitian ini bertujuan menentukan pelarut terbaik antara air, etanol, dan asam asetat serta kombinasi ketiganya untuk ekstraksi daun tanaman gandarusa menggunakan metode sonikasi terhadap kadar total fenolik serta aktivitas antioksidan (metode DPPH dan FRAP) secara in vitro. Hasil penelitian menunjukkan bahwa nilai verifikasi yang diperoleh terhadap kadar total fenolik dan aktivitas antioksidan tidak berbeda jauh dengan nilai prediksinya dari software Design-Expert metode simplex lattice design (SLD), yaitu sebesar 3,257 mg GAE/g bobot kering pada kadar total fenolik, 0,182 µmol TE/g bobot kering pada aktivitas antioksidan metode DPPH, dan 8,117 µmol TE/g bobot kering pada aktivitas antioksidan metode FRAP dengan nilai desirability sebesar 0,621. Hal ini dilihat dari nilai signifikansi (p-value) pada kadar total fenolik dan aktivitas antioksidan yang menunjukkan lebih besar dari 0,05., Gendarussa (Justicia gendarussa Burm. f.) is a medicinal plant that has antioxidant compounds to counteract free radicals due to the content of secondary metabolites such as phenolic compounds. The extracted phenolic content and antioxidant activity value can be affected by the use of extraction solvent. This study aimed to determine the best solvent between water, ethanol, and acetic acid and their combination for extracting the leaves of the gendarussa plant using the sonication method on total phenolic content and antioxidant activity (DPPH and FRAP methods) in vitro. The results showed that the verification value obtained for total phenolic content and antioxidant activity did not differ much from the predicted values from Design-Expert software simplex lattice design (SLD) method, which was 3.257 mg GAE/g dry weight on total phenolic content, 0.182 µmol TE/g dry weight on antioxidant activity of DPPH method, and 8.117 µmol TE/g dry weight on antioxidant activity of FRAP method with a desirability value of 0.621. This can be seen from the significance value (p-value) on total phenolic content and antioxidant activity which showed greater than 0.05.
Keyword: antioxidant activity, DPPH, FRAP, gendarussa, phenolic

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model