Judul: Total Fenolik dan Flavonoid serta Aktivitas Antioksidan Ekstrak Kulit Kayu Sengon (Paraserianthes falctaria (L.))
Abstrak: (Paraserianthes falcataria (L)) is widely used in wood industry and resulted many wastes. The leaf was found to have antioxidant activity, but the bark is still reused. The researches about (Paraserianthes falcataria (L)) bark that have been conducted was not studied to show potency of natural antioxidant. This research was performed to determine the antioxidant activity of (Paraserianthes falcataria (L)) bark extract. Phytochemical scavenging showed that aqueous, ethanol 70%, and 96% bark extracts were positively reacted to saponin, flavonoid, tanin, steroid, and triterpenoid test, while the only negative result was happened to alkaloid test. The highest ammount of total phenolic and flavonoid was found in ethanol 70% extract, those were 161.57 ± 3.93 GAE (mg/g) and 64.46 ± 2.94 CE (mg/g) respectively. The highest IC50 value was found in ethanol 96% extract with value of 40.17 ± 0.65 mg/L.
Keyword: antioxidant, flavonoid, phenolic, Paraserianthes falcataria (L) bark

Judul: Analisis Fitokimia Dan Aktivitas Antioksidan Ekstrak Daun Sengon (Paraserianthes falcataria (L) Nielsen) Menggunakan Metode DPPH
Abstrak: Kedawung (Mimosaceae family) has been shown to have high antioxidant content. Therefore, sengon leaf that belong to the Mimosaceae family is alleged to have potential as a source of natural antioxidants. Utilization of sengon leaf as food supplements with antioxidant activity has not been done. Therefore, this study aims to examine and to analyze the antioxidant activity of bioactive components. The antioxidant activity was determined by DPPH method and measured with a spectrophotometer at a wavelength of 517 nm. The results showed that the antioxidant activity is highest in the 96% ethanol extract of leaves sengon expressed as IC50, specifically 2.76 ppm. The antioxidant activity was caused by the content of secondary metabolites in the sengon leaf, such as alkaloids, saponins, flavonoids, tannins and phenolics, steroids and triterpenoids. The analysis showed that the antioxidant activity, total phenolic content (275.74 GAE mg/g) and total flavonoid (83.60 CE mg/g) sengon leaf are quite good and can be used as benchmark for natural antioxidant source.
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Judul: Solusi Geometri Schwarzschild untuk Dimensi 4+1 dengan Invarian Rotasi Isotropik
Abstrak: Metrik Schwarzschild merupakan solusi eksak pertama dari persamaan medan Einstein dengan mangasumsikan metrik statik dan simetris. Metrik Schwarzschild yang ditemukan oleh Karl Schwarzschild masih dalam dimensi 3+1, namun seiring dengan teori-teori terbaru yang menunjukkan bahwa alam semesta tidak hanya di dimensi 3+1. Maka melalui penambahan dimensi, tujuan penelitian ini memperoleh solusi pada geometri Schwarzschild untuk dimensi 4+1 dengan memodifikasi koordinat bola yang invarian rotasi isotropik dan melalui penurunan rumus seperti koordinat bola, simbol Christoffel, dan tensor Ricci. Selain mendapatkan solusi ini, metrik Schwarzschild dimensi 4+1 dapat digunakan sebagai metrik dasar untuk memperoleh solusi blackhole dan wormhole pada dimensi 4+1. Hasil akhirnya, dengan memanfaatkan modifikasi koordinat bola, metrik Schwarzschild dapat dibentuk sehingga diperoleh solusi geometri Schwarzschild untuk dimensi 4+1.
Keyword: metrik Schwarzschild, persamaan medan Einstein, modifikasi koordinat bola, penambahan dimensi, invarian rotasi isotropik