Judul: Potensi Antioksidan dan Sitotoksisitas Ekstrak Buah Ceremai (Phyllanthus acidus L.)
Abstrak: Ceremai is an indigenous plant from India, belongs to Euphorbiaceae family. Ceremai plnat not only be used as an ornamental plant but can also be used as a herbal supplement. Ceremai Plants reported to have efficacy as a hepatoprotective, antibacterial, antifungal, antioxidant potency is not known yet. The purpose of this study to prove the antioxidant activity and cytotoxicity of fruit Ceremai. Ceremai was extracted by maceration using 70% ethanol, 30% ethanol, and water as solvents. Results were determined by antioxidant activity using of 2,2-diphenyl-1-pikrilhidrazil (DPPH) and its cytotoxicity (biological potency) was determined by Brine Shrimp Lethality Test (BSLT) method. IC50 values were 26.06 ppm, 72.39 ppm, and 62, 17 ppm for water, 30% ethanol and 70% ethanol exstract respectively. LC50 values were produced from three extracts water, ethanol 30%, and 70% ethanol, they were 473.26 ppm, 486.78 ppm, 618.55 ppm. Water extract is the best antioxidant activity compared with 30% ethanol extract and 70% ethanol. However, ceremai fresh fruit extracts are not good for human consumption herbal supplements because it is toxic.
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Judul: Aktivitas Antioksidan Dan Potensi Hayati Dari Kombinasi Ekstrak Empat Jenis Tanaman Obat Indonesia
Abstrak: The crude ethanol extracts combination of four Indonesia medicinal plants namely Curcuma xanthorriza, Phyllanthus niruri, Andrographis paniculata, and Curcuma aeruginosa were examined for their antioxidant (radical scavenging) activity using 2,2-diphenyl-1-picrylhidrazyl (DPPH) free radical and biological activities or cytotoxicity using brine shrimp lethality test (BSLT). IC50 values for DPPH radical scavengeing activity ranged from 1.923 to 211.127 ppm, with extract combination of Curcuma xanthorriza and Curcuma aeruginosa (1:0:0:1) having the lowest value and therefore the most potent, and extract combination of Phyllanthus niruri, Andrographis paniculata, and Curcuma aeruginosa (0:1:1:1) having the highest value. LC50 values for BSLT ranged from 31.796 to 620.165 ppm, with extract combination of Curcuma xanthorriza, Phyllanthus niruri, Andrographis paniculata, and Curcuma aeruginosa (1:1:1:1) having lowest value and therefore the most potent, and extract of Curcuma aeruginosa (0:0:0:1) having the highest value. A positive correlation between antioxidant and biological activities of extract combination was obtained from combination (1:1:1:1), with antioxidant and biological or cytotoxicity values were 41.87 and 31.79 ppm, respectively.
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Judul: Bifurkasi Hopf pada siklus bisnis IS-LM tanpa dan dengan waktu tunda
Abstrak: One of business cycle models in dynamical economics is the IS-LM business cycle model with time delay, where the time delay lies in stock capital variables. It is a time delay between the existence of stock capital and the time to get ready to invest. In a model without time delay, changing the parameter of investment rate on income could affect the system stability. On the other hand, in a model with time delay, there exists critical time delay changing the system stability. This shows limit cycle, which can be concluded that Hopf bifurcation occurs
Keyword: Bogor Agricultural University (IPB), time delay, Hopf bifurcation, business cycle model