Judul: Aktivitas antidiabetes ekstrak air dan etanol daun sirsak secara in vitro melalui inhibisi enzim α-glukosidase
Abstrak: Soursop leaf is a part of the soursop plant used in traditional medicine and proven for antidiabetic agent through decrease in blood glucose level. However, the mechanism of decrease in blood glucose level has not been determined. The research was done to determine the activity of aqueous and ethanol extract of soursop leaf at 1, 1.50, 2% as α-glucosidase inhibitor, compared their activities with acarbose 1% as positive control and determine the mechanism of inhibition. Soursop leaf were extracted with ethanol 70% using maceration method and boiling water method. Aqueous and ethanol extract of soursop leaf were used for phytochemical assay and used for α-glucosidase inhibition method. The α- glucosidase activity was determined by measuring the p-nitrophenol release from the reaction of the enzyme and substrate p-nitrophenil- α-D-glucopiranoside (p- NPG) at 400 nm. The phytochemical analysis indicates that aqueous extract and ethanol extract contained alkaloid, flavonoid, saponin, tannin, and steroid. Both of them can inhibit α-glucosidase activity, but the mechanism of inhibition of the extract has not been able to determined. Aqueous extract can inhibit α-glucosidase activity up to 41.91%, and ethanol extract can inhibit α-glucosidase activity up to 89.33%. Acarbose as positive control can inhibit 93.84% of α-glucosidase activity.
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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: Simulasi persamaan keadaan bintang dengan pendekatan klasik dan relativistik
Abstrak: Komposisi bintang yang selalu berubah akanmempengaruhi massa dan radius bintang itu sendiri. Dimana semakin tua sebuah bintang, maka bintang akan didominasi oleh unsur-unsur berat. Dengan persamaan politrop dan metode Runge-Kutta orde 4 didapatkan radius dan massa bintang semakin berkurang seiring berkurangnya nilai Ye, sedangkan kerapatan semakin meningkat. Pendekatan terbaik terdapat pada nilai Ye sebesar 0.5 dimana didapatkan bahwa massa bintang katai putih sebesar 1.4Mo sesuai dengan massa Chandrasekhar dengan radius bintang 5000 km dan nilai kerapatan bintang sebesar 5.31x 106 g cm-3. Untuk massa bintang neutron diperoleh nilai 0.05Modan radius bintang sebesar 2300 km, sedangkan kerapatannya bintang neutron diperoleh sebesar 1.84 x 107 g cm-3 dengan menggunakan pendekatan relativistic. Pendekatan relativistic terbukti lebih baik untuk menentukan radius dan massa bintang, dengan pendekatan terbaik pada nilai Ye sebesar 0.5 yaitu pada bintang katai putih
Keyword: Composition of the stars, density of the stars, mass of the stars, radii of the stars