Judul: Aktivitas Ekstrak, Fraksi Pelarut, dan Senyawa Flavonoid Daun Sukun (Artocarpus altilis) terhadap Enzim α-Glukosidase sebagai Antidiabetes
Abstrak: Breadfruits plants is one of the herbal plants that its leaves has been reported to have biological properties, such as antioxidant, cytotoxic, antiinflammatory, antimicrobial, 5α-reductase enzyme inhibitors, tyrosinase enzyme inhibitors, and chatepsin K inhibitors. This study was conducted to investigate inhibitor activity of extracts and flavonoids compounds from breadfruit leaves against α-glucosidase enzyme using in vitro method. Extract and flavonoid compound are from Indonesian Science Intitute’s research. Inhibitor activity was determined by inhibition percentage and followed by determining the IC50 value. The results showed that extract ethanol, and three other solvent fraction (ethyl acetate, butanol, and hexane) has ability to inhibit α-glucosidase enzyme activity. Based on IC50 values and statistical tests, ethanol and ethyl acetate extracts which has a potential ability to inhibit α-glucosidase enzyme. Ethyl acetate fraction from breadfruit leaves (IC50=6,01 μg/mL) has a better to inhibit α-glucosidase activity than ethanol extracts (IC50=8,89 μg/mL). Based on fourth flavonoid derivative compounds results, which has the best active compound as an antidiabeticis (1-(2,4-dihydroxyphenyl)-3-[8-hydroxy-2-methil- 2-(4-methyl-3-pentenil)-2H-1-ben zopyran-5-yl]-1-propanon) with AC-31code (IC50=16,23 μM). This compound is a flavonoids derivatives compound in dihydrocalcon group.
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Judul: Total Fenolik, Flavonoid, dan Aktivitas Inhibisi Enzim α- Glukosidase Ekstrak dan Fraksi Ekstrak Daun Afrika (Vernonia amygdalina Del.)
Abstrak: Diabetes melitus merupakan gangguan metabolisme kronis yang ditandai dengan tingginya kadar gula darah dengan kasus kematian yang meningkat setiap tahunnya. Salah satu agen terapeutik antidiabetes yaitu inhibitor α-glukosidase. Penelitian terdahulu menunjukkan daun afrika (Vernonia amygdalina Del.) memiliki kemampuan inhibisi α-glukosidase. Penelitian ini bertujuan menentukan aktivitas inhibisi dan IC50 senyawa bioaktif hasil fraksinasi ekstrak etanol daun afrika terhadap enzim α-glukosidase. Daun afrika diekstraksi menggunakan etanol 70% kemudian difraksinasi bertingkat menggunakan n-heksana, etil asetat, n-butanol, dan air. Hasil fraksinasi dipekatkan menggunakan rotary evaporator dan dilakukan uji total fenolik, flavonoid, serta aktivitas inhibisi enzim dan menghitung nilai IC50 terhadap enzim α-glukosidase. Hasil penelitian menunjukkan fraksi etil asetat sebagai fraksi terbaik dengan kandungan total fenolik, total flavonoid, dan aktivitas inhibisi α-glukosidase paling tinggi dengan nilai IC50 sebesar 1.41 mg/mL.
Keyword: α-glucosidase, bitter leaf, flavonoid, IC50, phenolic

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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