Judul: Identifikasi dan Potensi Antioksidan Flavonoid Kulit Kayu Mahoni (Swietenia macrophylla King)
Abstrak: Mahogany bark as wood processing industrial waste has not widely used compared to other parts of mahogany. This research was conducted to identify the flavonoids from mahogany bark and its role as an antioxidant. Antioxidant activity of mahogany bark’s extract was measured by using two methods namely diphenil-1.1-2-picrylhydrazyl (DPPH) method and tiobarbituric acid (TBA) method. Identification of flavonoids (quersetin) was performed by using HPLC and TLC. Antioxidant activity of flavonoids (quersetin) was measured by using DPPH method.Inhibition activity of mahogany bark’s extract on DPPH method for the extraction of methanol, n-hexane, diethyl ether, ethyl acetate, vitamin E (positive control) and water at concentrations of 50 ppm are respectively for 81.33%, 12.74%, 23:40%, 65.54 %, 30.42%, and 68.04%. The inhibition activity of mahogany bark’s extract on TBA methods for methanol fraction 200, 100, 50 ppm was 59.81%, 59.02%, 58.96%. Extraction of water 200, 100, 50 ppm was 54.65%, 49.01%, 43.09%. Vitamin E 200, 100, 50 ppm was 40.91%, 36.48%, 27.15%. Kuersetin content in the sample is 16 mg/100g sample. Inhibition activity of antioxidants on kuersetin as 50, 100, and 200 ppm for 87.2%, 89.1%, 92.8%.
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Judul: Kandungan Flavonoid Kulit Kayu Mahoni (Swietenia macrophylla King.) dan Toksisitas AkutnyaTerhadap Mencit
Abstrak: Mahoni bark represent industrial waste product of wood industry which have low economic value. Mahoni bark has been known as antioxidant. That activity can’t be separated phytochemicaly compound, flavonoid. This research aim to determine active compound content and total flavonoid concentration of mahoni bark which extracted by water and methanol. Phytochemical analysis done by Harborne methods (1987) and total flavonoid concentration determination done by spectrophotometry methods. LD50 determination of acute toxicity done by Reed-Muench methods. Alkaloid, flavonoid, tannin, saponin, and triterpenoid known represent at water and methanol extract. Total flavonoid concentration of water and methanol extract are 0.0402% (b/b) and 0.2016% (b/b). LD50 of water extract is 21428.91 mg/kg BW and LD50 of methanol extract is 16330.52 mg/kg BW. According to Gleason classification, both of extract included in the non toxic materials. Result of histopatology analysis shown water extract tend to destroy kidney and methanol extract tend to destroy liver. Microscopic picture show tendency of heavier damage effect of administration of both bark extract at dose more than 5000 mg/kg BW.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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