Judul: Aktivitas Antioksidan dan Bioaktivitas Kombinasi Fraksi Polifenol Daun Syzygium polyanthum dengan Guazuma ulmifolia.
Abstrak: Senyawa polifenol dalam daun salam (Syzygium polyanthum (Wight.) Walp.) dan daun jati belanda (Guazuma ulmifolia Lam.) berkhasiat sebagai antioksidan alami dan berkorelasi positif dengan aktivitas antikanker yang menunjukkan adanya bioaktivitas. Penelitian ini bertujuan menentukan aktivitas antioksidan kombinasi fraksi polifenol daun salam (SLM) dengan jati belanda (JBL) dan potensi bioaktivitasnya. Tiga kombinasi komponen digunakan dalam penelitian ini, yaitu: SLM=JBL (A), SLM<JBL (B), SLM>JBL (C). Fraksi polifenol diperoleh melalui fraksinasi ekstrak kasar etanol dengan n-heksana dan kloroform. Aktivitas antioksidan ditentukan dengan metode 2,2-difenil-1-pikrilhidrazil (DPPH) pada λ 516 nm. Potensi bioaktivitas ditentukan dengan Brine Shrimp Lethality Test (BSLT) melalui analisis Probit. Semua kombinasi memiliki aktivitas antioksidan sangat kuat (IC50 ≤ 50 μg/mL) dengan nilai IC50 18.05 μg/mL (C), 24.61 μg/mL (A), dan 40.56 μg/mL (B). Peningkatan kekuatan antioksidan berbanding lurus dengan peningkatan jumlah salam dalam kombinasi. Semua kombinasi bersifat sitotoksik dan memiliki potensi bioaktivitas (LC50<1000 μg/mL) dengan rentang nilai LC50 antara 55.05-153.76 μg/mL.
Keyword: antioksidan, jati belanda, kombinasi, salam, sitotoksik

Judul: Aktivitas Antioksidan dan Sitotoksisitas Metabolit Sekunder Daun Salam (Syzygium polyanthum Wight.) dan Daun Jati Belanda (Guazuma ulmifolia Lamk.)
Abstrak: Secondary metabolites from salam (Syzygium polyanthum Wight.) and jati belanda (Guazuma ulmifolia Lamk.) leaves can potentially be optimized for the utilization of these leaves as antioxidants. This research aimed to compare antioxidant activity and cytotoxicity of crude extracts of flavonoid, tanin, and hydroquinone of both type of leaves. Total phenolic and flavonoid compound was measured trough colorimetry, then the antioxidant activity was measured using 1.1-diphenil-2-picrylhydrazyl (DPPH) method and cytotoxicity test use brine shrimp lethality test (BSLT). Total phenolic value of salam leaves (614.70 mg GAE/100 g dried leaves) was higher when compared to jati belanda leaves (566.824 mg GAE/100 g dried leaves). Similarly, total flavonoids of salam leaves (434.234 mg QE/100 g dried leaves) was higher when compared to jati belanda leaves (246.214 mg QE/100 g dried leaves). This value is supported by IC50 values with DPPH method and LC50 values with cytotoxicity test showed the lowest IC50 and LC50 is flavonoid extract of salam leaves (IC50 = 10.833 μg/mL and LC50 = 328.427 μg/mL). Flavonoid of Salam leaves is the secondary metabolites with the best antioxidant activity and bioactivity effect.
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Judul: Model Input-output dalam Masalah Network Flow
Abstrak: Production process is a process, which is done by industry, to transform input into output. According to the type of output and its activity, industry can be classified into various sectors, which are connected to each other. Therefore, a model to analyze the connection among sections is needed. The model is known as input-output model (IO model). IO model presents an IO table, which shows informations about the transaction between goods and services in each economic sector. Furthermore, the IO model also shows that the amount of all input is the same as the amount of all output. In this paper, the transaction of each economic sector in IO table is analyzed using network flow theory. The formulated network flow problem implies that each sector represents partly as a producer and also as a consumer. This paper also solves a minimum cost circulation problem.
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