Judul: Isolasi Fraksi Flavonoid sebagai Inhibitor Enzim α-Glukosidase dari Buah Mahkota Dewa
Abstrak: Mahkota dewa (Phaleria macrocarpa) empirically recognized as anti-diabetic. This claim requires further analysis, one of it by enzymatic inhibition assay using α-glucosidase enzyme. This intestinal enzyme produce in the jejunum catalyzed the breakdown of glycogen to glucose which increased blood sugar level therefore, elevating the risk of diabetes. Efforts to inhibit this enzyme could decrease postprandial blood sugar level. The aim of experiment was to determine the most active flavonoid subgroup which inhibited α-glucosidase enzyme of fruit etanol extract from mahkota dewa initiated with liquid partition and was continued with flash chromatography partition. Fruit pericarp is macerated using 3 different solvents (water, ethanol 96%, and n-hexane). Dry extract was analyzed for its water content, ash content, phytochemical content, and inhibition activity of α-glucosidase enzyme using modified Kawaniski method. The most active isolate is analyzed further using flash chromatography. Fruit pericarp water concentration was 9,42%. Phytochemical compound of the extracts were alkaloids, flavonoids, tannins. saponins, steroids, but do not contain triterpenoids. Amyl alcohol fraction has the highest inhibition to α-glucosidase of 40,04%, for the ethyl acetate fraction only 25,26%, and glucobay as positive control was 97,45%. Further analysis with flash chromatography using solvent of the best resolution was chlorofom:methanol with ratio of 9:1 which showed that amyl alcohol fraction contain flavonoid from several classes of isoflavon, flavon, flavonol, and flavanon. This result showed that the flash chromatography partition has not succeeded to separate the subgroup of flavonoid which was active to inhibit α-glucosidase enzyme.
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Judul: Senyawa Golongan Alkaloid Ekstrak Buah Mahkota Dewa sebagai Inhibitor α-Glukosidase
Abstrak: The crown of God Fruit is believed to cure diabetes mellitus. The objective of this study is to investigate the highest inhibitory activity of α-glucosidase from alkaloid extract of the fruit by in vitro method. Three levels of ripeness used in this study i.e. dark red, red-greenish, and green-reddish. The result showed that alkaloid from red-greenish crown of god fruit extract had the highest inhibition activity of 36.80%, but was lower than acarbose which has 97.73%. Fractionation of alkaloid extract obtained 5 fractions from red-greenish crown of god fruit was done by column cromatography with the eluent of chloroform:ethanol (17:3). Inhibiton activity of each fractions to α-glucosidase was examined and it was obtained that the most active fraction was fraction 5 with inhibition activity value of 87.29%. Further identification of fraction 5 with infrared spectrophotometrer showed the presence of possible functional groups; there were –OH stretching at 3408.87 cm-1 of wave-number, C=C aromatic stretching at 1616.91 cm-1 and C-N amine aromatic stetching at 1279.88 cm-1, which was strengthened by overtone band at 617.21 cm-1. Based on those result, it could be predicted that the alkaloid compound was alkaloid with nitrogen atom in the aromatic ring.
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Judul: Sistem Pakar Perencanaan Jalur Saluran Transmisi dan Dimensi Pondasi Strap Footing Untuk Tower Listrik Saluran Udara Tegangan Tinggi (SUTT)
Abstrak: Pusat-pusat pembangkit tenaga listrik terutama yang menggunakan tenaga air, biasanya terletak jauh dari pusat-pusat beban. Dengan demikian, tenaga listrik yang telah dibangkitkan harus disalurkan melalui saluran-saluran transmisi. Saluran-saluran ini membawa tenaga listrik dari pusat pembangkit ke pusat-pusat beban baik langsung maupun melalui gardu-gardu induk. Pada penelitian ini, saluran transmisi yang diteliti adalah Saluran Udara Tegangan Tinggi (SUTT) berdaya 150 Kv. Secara ideal jalur saluran transmisi untuk SUTT yang terdiri dari beberapa tower adalah sebuah garis lurus. Akan tetapi dalam aplikasi lapangannya tidak demikian. Bisa saja berupa titik-titik dengan lokasi yang tidak beraturan, karena disesuaikan dengan kondisi lapangan. Setelah titik-titik rencana jalur saluran transmisi lokasi tower dapat dibuat, hal lain yang perlu didisain adalah dimensi pondasi tower tersebut. Apabila kita salah memilih atau merencanakan pondasi, maka kesalahan tersebut mengakibatkan terjadinya kerusakan pada struktur bangunan lainnya. Pondasi yang dipakai adalah pondasi telapak kombinasi (strap footing) dengan perbaikan tanah menggunakan pondasi sumuran (bore pile).
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