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: Optimization of Extraction of Phenolic Content and  Antioxidant Activity of Gandarusa (Justicia gendarussa Burm f.) Leaf with  Response Surface Methodology (RSM)
Abstrak: Ektraksi daun gandarusa (Justicia gendarussa Burm f.) dapat dipengaruhi oleh pelarut, suhu, dan waktu ekstraksi. Penelitian ini bertujuan menentukan suhu, waktu, dan konsentrasi pelarut optimum kadar total fenolik dan aktivitas antioksidan ekstrak etanol daun gandarusa dengan metode Respon Surface Methodology (RSM). Parameter uji yang dilakukan terhadap ekstrak daun gandarusa antara lain penentuan kadar total fenolik dengan metode Folin-Ciocalteu serta aktivitas antioksidan DPPH dan FRAP. Variabel bebas yang digunakan dalam desain eksperimen adalah konsentrasi etanol (10%, 50%, dan 90%), suhu (30℃, 45℃, dan 60℃) dan waktu ekstraksi (60, 120, dan 180 menit). Kadar total fenolik menunjukan korelasi yang positif dan signifikan terhadap aktivitas antioksidan FRAP daun gandarusa. Kondisi optimal untuk kadar total fenolik dan aktivitas antioksidan DPPH dan FRAP ekstrak daun gandarusa yaitu pelarut etanol 16,8%; suhu 30℃; dan waktu 180 menit. Nilai prediksi dan nilai verifikasi kadar total fenolik dan aktivitas antioksidan DPPH tidak berbeda secara signifikan., Extraction of gandarusa leaves (Justicia gendarussa Burm f. ) can be affected by solvent, temperature, and extraction time. This study aimed to determine the optimum temperature, time, and concentration of solvents, the total phenolic contents and antioxidant activity of gandarusa leaf ethanol extract by the Response Surface Methodology (RSM). Parameters of the test carried out on the extract of gandarusa leaf include determination of total phenolic contents using the Folin-Ciocalteu method as well as the antioxidant activity of DPPH and FRAP. The independent variables used in the experimental design were ethanol concentration (10%, 50%, and 90%), temperature (30℃, 45℃, and 60℃) and extraction time (60, 120, and 180 minutes). Total phenolic content showed a positive and significant correlation to the antioxidant activity of FRAP gandarusa leaves. Optimal conditions for total phenolic content and antioxidant activity of DPPH and FRAP of gandarusa leaf extract are 16,8% ethanol solvent; temperature 30℃; and time 180 minutes. The predictive value and verification value of the total phenolic content and antioxidant activity of DPPH did not different significantly.
Keyword: Antioxidant activity, gendarussa, independent variables, phenolic, RSM

Judul: Asymptotic Distribution of Estimator for the Intensity Function of a Doubly Periodic Poisson Process
Abstrak: In this manuscript, estimation of the intensity function of a doubly periodic Poisson process is discussed. It is assumed that only a single realization of the Poisson process is observed in a bounded window [0,n]. It is also assumed that the period of the intensity function is known. The rate of consistency and asymptotic normality of the estimator are formulated. Finally, a confidence interval for the local intensity function is also formulated.
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