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: Peroksidasi Lipid pada Tikus Hiperkolesterolemia selama Pemberian Ekstrak Kulit Batang Mahoni (Swietenia macrophylla)
Abstrak: Mahogany’s bark is known as wood industrial waste that contains potential secondary metabolites. However, its potency as an antioxidant, especially in rats which are subjected to hypercholesterolemic treatment, has not been carried out. The aim of this study was to test the effect of mahogany’s water extract consumption on the concentration of lipid peroxides in hypercholesterolemic rats. Thirty five male rats were divided into 5 groups (n=7) namely normal group fed with standard rat chow, hypercholesterolemic group (HK) fed with cholesterol chow (1,5%) and PTU (0,5 mg/KgBW), lovastatin group (HK+lovastatin 0,2857 mg/KgBW), E1 group (HK+ mahogany’s extract 4,2 mg/KgBW), and E2 group (HK+mahogany’s extract 21 mg/KgBW). Experiments were carried out for 8 consecutive weeks. The concentration of lipid peroxides in blood were measured with thiobarbituric acid assay at week 0, 2, 4, 6, and 8 using spectrophotometer. Cholesterol chow (0.86%) and PTU increased the lipid peroxides concentration of HK group by 20.92% compared to the normal group (3.380±0.436 nmol/mL). However, it is not statistically significant (p=0.239). The lipid peroxides concentration in E1 and E2 weren’t increased and relatively similar to normal group at concentration of 2.353±0.196 nmol/mL, 2.786±0.256 nmol/mL, and 2.673±0.279 nmol/mL, respectively. Although it is not statistically significant, both doses of extracts tend to prevent the lipid peroxidation in the rat’s blood.
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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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