Judul: Aktivitas Antioksidan, Kadar Fenolik, dan Flavonoid Total Tumbuhan Suruhan (Peperomia pellucida L.Kunth)
Abstrak: Suruhan (Peperomia pellucida L. Kunth) merupakan tumbuhan semak yang tersebar luas di seluruh wilayah Indonesia dan memiliki khasiat untuk meredakan nyeri rematik, sebagai antikanker, dan antibakteri. Penelitian ini bertujuan untuk menguji aktivitas ekstrak herba suruhan sebagai antioksidan alami dan mengukur kadar fenolik dan flavonoid total dalam suruhan. Sampel yang digunakan berupa ekstrak etanol 70% dan ekstrak air dari herba suruhan. Ekstrak didapat dengan metode maserasi dan dilakukan uji antioksidan dengan metode DPPH kemudian dilakukan uji kandungan fenolik dan flavonoid total ekstrak serta dianalisis korelasi kedua senyawa ini terhadap aktivitas antioksidannya. Rendemen yang dihasilkan oleh ekstrak etanol 70% sebesar 20.43 ± 3.33% sedangkan rendemen ekstrak air sebesar 10.03 ± 2.85%. Kedua ekstrak menunjukkan aktivitas antioksidan dalam penangkapan radikal bebas DPPH. Nilai IC50 ekstrak air sebesar 256.67 ± 21.65 ppm yang diikuti oleh ekstrak etanol sebesar 297.79 ± 17.75 ppm. Kandungan fenolik ekstrak air sebesar 755.79 ± 65.87 mg TAE/g dan ekstrak etanol sebesar 622.46 ± 179.43 mg TAE/g. Kandungan flavonoid total ekstrak etanol sebesar 4.058 ± 0.352 mg QE/g dan ekstrak air sebesar 0.67 ± 0.352 mg QE/g. Kandungan total fenol berkorelasi linier dengan aktivitas antioksidan tetapi aktivitas antioksidan tidak memiliki korelasi dengan flavonoid.
Keyword: Suruhan, Antioxidant, Flavonoid, Phenolic

Judul: Aktivitas Antioksidan, Kadar Fenolik, dan Flavonoid Tumbuhan Suruhan (Peperomia pellucida L. Kunth)
Abstrak: Suruhan (Peperomia pellucida L.Kunth) is the bush had widespread in Indonesia and has efficacy as arthritis pain relief, anticancer, and antibacterial. The aim of this study was testing the activity of suruhan’s herb extracts as natural antioxidants and measured the total phenolic and flavonoid content in suruhan. The sample used in the form of 70% ethanol extract and aqueous extract of the suruhan. The extract obtained by maceration method and tested antioxidants with DPPH method and then tested the content of total phenolic and flavonoid extracts and analyzed the correlation of these compounds to antioxidant activity. The yield of 70% ethanol extract was 20.43 ± 3.33% whereas the yield of aqueous extract was 10.03 ± 2.85%. Both of extract has produced the antioxidant activity of free radical DPPH capture. IC50 values of aqueous extract of 256.67 ± 21.65 ppm, followed by ethanol extract of 297.79 ± 17.75 ppm. Total phenolic content of aqueous extract was 755.79 ± 65.87 mgTAE/g and ethanol extract was 622.46 ± 179.43 mg TAE/g. Total flavonoid content of ethanol extract was 4.058 ± 0.352 mg QE/g and aqueous extract was 0.67 ± 0.352 mg QE/g extract for aqueous. The phenol content have linier correlation with their antioxidant activity but the flavonoid content didn’t have correlation with antioxidant activity.
Keyword: 

Judul: Analysis of Unequal Income Distribution with Cobb-Douglas Production Function
Abstrak: This paper studies the economic growth model by Moav (2002). Moav model shows the existence of unequal income distribution between low-income with high-income community. That kind of unequal income distribution is caused by uneven distribution of income. On this Moav model, there is one area called the threshold. Threshold becomes a benchmark to determining whether a society is categorized into low- or high- income community. The production function used in this paper is the Cobb-Douglas function. The dynamics of this model is described as difference equation of low-income, threshold, and high-income community. Simulation study on the model is carried out using Maple 13 and Mathematica 7.0 software. Overall, from the observed case, high-income community will reach a stable condition earlier, followed by the threshold, and then the low-income community.
Keyword: