Judul: In Vitro Inhibition of Xanthine Oxidase by Roselle (Hibiscus sabdariffa) and Ciplukan (Physalis angulata) Extracts.
Abstrak: The enzyme xanthine oxidase catalyses xanthine oxidation into uric acid, which plays a crucial role in gout. Roselle and ciplukan as common medicine herbs used in many traditional treatment because it contains secondary metabolite compounds potentially as xanthine oxidase inhibitory. In this research, to water and ethanol extracts from roselle and ciplukan was conducted phytochemical assay, toxicity to Artemia salina , herbs, extract assay, and inhibition assay to xanthine oxidase activity by in vitro, and than to compared allopurinol as positive control. Uric acid crystal growth rate from saturated solution with turbidimetry method was also observed. Ciplukan phytochemical assay showed that flavonoid, tannin, saponin, alkaloid, and steroid compounds but alkaloid and steroid were not detected in roselle extract. Probit analysis to water and ethanol extracts from roselle calyxes and ciplukan herbs showed lethal concentration 50 value (LC50) of 96.95, 40.03, 252.79, and 63.83 ppm, respectively. Ethanol and water extracts from ciplukan (70.08% and 43.66%) showed higher inhibition activity than ethanol and water roselle extracts (35.53% and 20.42%) but still lower than alloprinol (98.63%) in concentration 100 ppm. Among 4 extracts, only ciplukan ethanol extract had the lowest Inhibition concentration 50 value as 74.49 ppm indicated that it is potential to be developed as medicine. Turbidimetry method was not successful for observing uric acid crystal growth.
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Judul: Aktivitas Inhibisi Xantin Oksidase oleh Ekstrak Air dan Etanol Anting-anting (Acalypha indica L.)
Abstrak: Gout is a disorder in which sodium urate crystals are deposited in and aroud joints. Anting-anting is an original plant of Indonesia that often used in gout therapy The aim of this research for identify phytochemical contents, testing cytotoxic activity and xanthine oxidase inhibition test by water and ethanol extract of anting-anting. In this research, it committed phytochemical test by Harborne Method, cytotoxic test by Brine Shrimp Lethality Test (BSLT), and inhibition test of xanthine oxidase activity by spectrofotometry method. The phytochemical assay result of water and ethanol extract of anting-anting, each of them showed us an existing flavonoid, tannin, saponin, alkaloid and steroid compound. The result of probit analysis of the water and ethanol extract of anting-anting indicated the lethal concentration value 50 (LC50) respectively 446.629 and 156.629 ppm. Highest inhibition by water extract 450 ppm as 66.78%, ethanol extract 150 ppm as 65.84%, and allopurinol 150 ppm as 74.09%. Ethanol extracts of anting-anting still can said to be potential as inhibitor of xantin oksidase and can be use as anti uric acid herb
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Judul: Pengenalan pembicara dengan jaringan syaraf tiruan Backpropagation
Abstrak: Masalah pengenalan pembicara terbagi menjadi dua bagian, yaitu identifikasi pembicara (menentukan identitas pembicara) dan verifikasi pembicara (melakukan verifikasi identitas yang diklaim oleh pembicara). Pengenalan pembicara termasuk dalam masalah nonalgorithmic maka dapat digunakan jaringan syaraf tiruan (JST) untuk mengenali pola-pola suara pembicara. Dalam penelitian ini dibangun suatu sistem yang dapat melakukan pengenalan pembicara menggunakan JST backpropagation. Sebelum diproses dalam JST data suara terlebih dahulu diproses dengan proses-proses sinyal digital melalui suatu proses feature extraction ditambah dengan proses feature selection. Proses feature extraction dilakukan dengan analisis cepstral dan feature selection dilakukan dengan principal component analysis. Hasil dari JST selanjutnya diolah oleh model pembuatan keputusan. Model pembuatan keputusan dalam sistem identifikasi akan menentukan identitas pembicara dan dalam sistem verifikasi akan menerima atau menolak klaim yang diajukan oleh pembicara. Sistem pengenalan pembicara yang dibangun mampu mengidentifikasi dengan tingkat generalisasi tertinggi sebesar 92,3077% dan melakukan verifikasi dengan nilai equal error rate sebesar 6,5657%.
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