Judul: Aktivitas antioksidan ekstrak selaginella
Abstrak: Selaginella (Selaginellaceae) is a pteridophyte plant, having a lot of potential and benefits as food material and pharmaceutical. As a medicinal plant, Selaginella has been used as anti-cancer, anti-tumor, and antioxidant. The objective of the study was to analyze the potential of S. ornata, S. plana, and S. willdenovii extract as antioxidant by measuring lipid peroxidation (MDA level) and Superoxide Dismutase (SOD) activity. This experiment was started with LD50 test of three kinds of Selaginella extract as preliminary experiment. The experiment was designed as complete randomize design with two factors. The first factor was three species of Selaginella and the second factor was four doses of Selaginella extracts, which were 0, 0.3, 0.6, and 1.2 g extract/kg bw. The result showed that at the dose of 0.6 g extract/kg bw, Selaginella extract could decrease the MDA level to the lowest level. The dose of 0.3 g extract/kg bw could increase the SOD activity. Among the three species of Selaginella extract, S. ornata showed the best antioxidant activity.
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Judul: Biodiversity, Ethnobotany, and Antioxidant Ability of Selaginella spp. from Halimun-Salak Mountain National Park (TNGHS).
Abstrak: Biodiversity and ethnobotany of Selaginella were studied in Halimun-Salak Mountain National Park (TNGHS) to describe the diversity and the use of Selaginella as medicinal plant. The diversity study of Selaginella was done by exploring Selaginella at 6 sampling points. The ethnobotany study of Selaginella was done by interviewing respondents at the villagers around Bunder Mountain, Citalahab Sentral, and Kasepuhan Adat Banten Kidul. There were eight species Selaginella found in TNGHS which were S. willdenovii, S. ornata, S. plana, S. intermedia, S. involvens, S. alutacia, S. subalpina and one species that has not been identified yet. The first two species were found dominantly in this location. The community in the location of study called Selaginella as paku rane. At the villages around Bunder mountain and Citalahab Sentral, Selaginella is also called as rande. The plant was traditionally used as fresh vegetables, postnatal and wound treatment, and body fitness maintenance. Antioxidant ability of Selaginella was tested by performing hydroxyl radical scavenging activity based on Fenton reaction. Three species of Selaginella were tested their hydroxyl radical scavenging activity. S. plana was the most potential species as an antioxidant followed by S. ornata and S. willdenovii. The crude extract of S. plana showed the best antioxidant activity at concentration of 75 μg/ml. Key words: Selaginella, biodiversity, ethnobotany, antioxidant, Halimun-Salak Mountain National Park (TNGHS)
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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