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).
Keyword: 

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.
Keyword: 

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.
Keyword: