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: Daya Inhibisi Ekstrak Rimpang Jahe Merah dan Kulit Kayu Manis terhadap Aktivitas Enzim Siklooksigenase 2 dan Enzim Xantin Oksidase Secara In Vitro
Abstrak: Red ginger and cinnamon are medicine plants which can be used as anti-inflammation and lowering uric acid level in blood. In this study, water and ethanol extracts of red ginger root and cinnamon bark have been assayed for phytochemical constituent, toxicity by brine shrimp lethality test, and in vitro inhibition of cyclooxygenase 2 and xanthine oxidase activities. Diclofenac, ibuprofen and allopurinol were used as positive control. Based on phytochemical assay, water and ethanol extracts of red ginger root contained alkaloids, steroids, and flavonoids, while its water extract of cinnamon bark contained kaloids, triterpenoids, saponins, flavonoids, and tannins. The result of probit analyses of water and ethanol extracts of red ginger root and cinnamon bark showed that their LC50 values were 144 ppm, 108 ppm, 125 ppm, and 107 ppm, respectively. Ethanol extract of red ginger root showed very low inhibitory effect to cyclooxygenase 2 activity (23.81%) as compared to diclofenac (95,43%) and ibuprofen (93,59%). Water and ethanol extracts of cinnamon bark that have inhibitory effect more than 50% to xanthine oxidase were, 54.64% and 56.80%, with their IC50 values of 70 ppm and 63 ppm, respectively. Allopurinol exhibited the highest inhibitory effect (97.91%). The value of inhibitory effect showed that ethanol extract of red ginger root have low potential as inhibitor to cyclooxygenase 2 and rheumatoid drugs; water and ethanol extracts of cinnamon bark can be considered as potential as inhibitor of xanthine oxidase and can be used for uric acid drugs.
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Judul: Massa Graviton Berdasarkan Teori De Rham- Gabadadze-Tolley Dalam Model Alam Semesta Datar Friedmann-Lemaitre- Roberson-Walker
Abstrak: Teori Relativitas Umum memprediksi ekspansi alam semesta diperlambat, sedangkan hasil observasi supernova tipe Ia mendapati ekspansi alam semesta dipercepat. Teori Relativitas Umum dimodifikasi melalui pendekatan teori gravitasi bermassa nonlinier oleh de Rham-Gabadadze-Tolley (dRGT). Massa graviton dimunculkan untuk dinamika skala sangat besar. Persamaan medan Einstein teori dRGT dapat dirumuskan dari prinsip variasi. Selanjutnya dengan memilih metrik datar Friedmann-Lemaitre-Roberson-Walker dapat diformulasikan bentuk persamaan Friedmann yang relevan dengan model ekspansi dipercepat. Hasil akhirnya, dengan membandingkan massa graviton dari metode Extremely Low Energy (ELE) dapat dihitung massa kritis graviton yaitu sekitar - . .
Keyword: massa graviton, teori dRGT, persamaan medan Einstein, persamaan Friedmann, ekspansi alam semesta dipercepat