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: Aktivitas Antioksidan Superoksida Dismutase Pada Hati Tikus Hiperkolesterolemia Yang Diberi Ekstrak Kulit Mahoni (Swietenia macrophylla)
Abstrak: Mahoni’s stem bark is wood industrial waste that rich in secondary metabolites. Research about its antioxidant potency has been done previously. This research was performed to study about the mahoni’s bark extract mechanism on lowering lipid peroxidation by determining the activity of endogenous antioxidant in the liver. Thirty five male rats were divided into 5 groups (n=7) normal, hypercholesterolemic, lovastatin, extract 1, and extract 2 group. Normal group fed with standard rat chow, hypercholesterolemic group (HK) with cholesterol chow (1,5%) and PTU (0,5 mg/KgBW), lovastatin group (HK + lovastatin 0,2857 mg/KgBW), E1 group (HK+ mahoni extract 4,2 mg/KgBW), and E2 group (HK + mahoni extract 21 mg/KgBW). Experiments were carried out for 8 consecutive weeks. The rat liver superoxide dismutase (SOD) antioxidant activity were determined by calculating the inhibition percentage of pyrogallol autooxidation process became purpurogallin by SOD, total formed purpurogallin was measured using spectrophotometer with 340 nm wavelength. The SOD antioxidant activities in normal group of rats was 47.96±12.37%. There was not any significant SOD antioxidant activities difference between all rats group of treatment (=0.05). These result showed that mahoni’s bark extract roles as antioxidant in rats was achieve not by increasing the activity of superoxide dismutase but by other mechanism.
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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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