Judul: Penghambatan Peroksidasi Lipid oleh Ekstrak Kulit Batang Mahoni (Swietenia macrophylla King) pada Tikus Hiperurisemia
Abstrak: Increased blood uric acid (hyperuricemia) has been reported in the increased of lipid peroxidation. To overcome lipid peroxide formed, natural antioxidant compounds could be used, one of them is mahony bark extract. The purposes of this research are to analyze lipid peroxidation level and to determine the effect of mahony bark extract on blood lipid peroxide concentration in hyperuricemic rats. A total of 33 rats divided into 5 groups consist of normal control, hyperuricemic control (HU I), allopurinol (HU II, 3.3 mg/Kg BB), HU and water extract (HU III, 500 mg/Kg BB), and HU and methanol extract (HU IV, 500 mg/Kg BB). Hyperuricemia was induced by chicken liver juice fed in 28 days, thus, extract were given everyday in 7 days after, furthermore experiment was done in 35 days. Serum lipid peroxide concentration was analyzed in day-0, 14, 21, 28, and 35 using spectrophotometry method at 532 nm. The result of this research showed that average lipid peroxide concentration of all rats before experiment is 0.586±0.177 nmol/mL. Hyperuricemic induction had increased lipid peroxide concentration up to 11.23%. There was an increased of 11.41% after supplementation of allopurinol, on the contrary water extract could decrease blood lipid peroxide concentration over 26.86% (p= 0.006).
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Judul: Khasiat antioksidasi ekstrak kulit kayu mahoni (Swietenia macrophylla King) terhadap peroksidasi lipid pada hati tikus hiperurisemia
Abstrak: The bark of mahogany (Swietenia macrophylla King) contains bioactive compounds, which has been reported as an antioxidant. But there had been very few in vivo evidence of the antioxidant effectiveness on the liver lipid peroxidation in hyperuricemic rats. This study aimed to test the effect of mahogany (Swietenia macrophylla King) bark extracts against lipid peroxidation in hyperuricemic rat liver. Thirty three rats were divided into 5 groups, namely normal, hyperuricemic (HU), allopurinol (HU I), aqueous extract (HU II) and methanol extract (HU III). Hyperuricemic induction was carried out by giving the juices of chicken liver and sodium carboxyl methyl cellulose 0.5%. The induction was administered orally for 4 weeks with dosage of 25 g/kg BW. Afterwards, rat were administered by aqueous extract and methanol extract at 500 mg/Kg BW day for 7 days. Liver lipid peroxides analysis was determined by using thiobarbituric acid (TBA) method. The results showed that the lipid peroxide concentrations of hyperuriemic, allopurinol and methanol extracts group were 101.51 ± 54.74 nmol/gram, 108.55 ± 45, nmol/g and 101.04 ± 26.68 nmol/gram, respectively. The aqueous extract has the antioxidants effect on rat liver lipid peroxidation with the concentration of 63.57 ± 16.84 nmol/g, smaller than that of the normal group (93.83 ± 29.55 nmol/gram). Statistically, the aqueous extract tend to decrease the liver lipid peroxide concentration of hiperuricemic rat by 32.25% (p = 0.054).
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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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