No abstract

Compositional changes of rice germ oils prepared at different roasting temperatures (160-180°C) and times (5-15 min) from rice germ were evaluated and compared with those of unroasted rice germ oil. The color development and phosphorus content of oils increased significantly as roasting temperature and time increased, whereas the FA compositions of rice germ oils did not change with roasting temperature and time. Four phospholipid classes, i.e., PE, PI, PA and PC, were identified. PE had the lowest stability under roasting conditions. There were no significant differences in γ-oryzanol levels of rice germ oils prepared at different roasting temperatures and times. Four tocopherol isomers (α-, β-, γ-, and δ-tocopherol) and three tocotrienol isomers (α-, γ-, and δ-tocotrienol) were identified, but no β-tocotrienol was detectable. The content of α-and γ-tocopherol in rice germ oil gradually increased as roasting temperature and time increased.

Capsaicin (8-methyl-N-vanillyl-6-nonenamide) is a pungent ingredient of red peppers, and has been reported to reduce body weight gain and adiposity in rodents. The present study investigated the effects of capsaicin on lipid catabolism in differentiated 3T3-L1 adipocytes. Capsaicin decreased the intracellular lipid content in a concentration-dependent manner. The release of glycerol into the medium was increased by the addition of capsaicin. The mRNA levels of genes involved in lipid catabolism such as hormone sensitive lipase (HSL), carnitine palmitoyl transferase-Iα (CPTI-α) and uncoupling protein 2 (UCP2) were up-regulated significantly. These results suggest that capsaicin exerts its lipolytic action by increasing the hydrolysis of triacylglycerol in adipocytes, and that these effects are mediated at least partially by regulation of the expression of multiple genes that are involved in the lipid catabolic pathway, such as HSL and CPT-Iα, and those involved in thermogenesis such as UCP2.

This study investigated the antiobesity effect of garlic in diet-induced obese mice. Male C57BL/6J mice were fed a high-fat diet (45% fat) for 8 wk to induce obesity. Subsequently, they were fed a high-fat control diet, high-fat diets supplemented with 2%, or 5% garlic (wt:wt) for another 7 wk. Dietary garlic reduced body weight and the mass of various white adipose tissue deposits and also ameliorated the high-fat diet-induced abnormal plasma and liver lipid profiles. Garlic supplementation significantly decreased the mRNA levels of adipogenic genes in white adipose tissues (WAT). However, consumption of garlic increased the expression of mRNA for uncoupling proteins in brown adipose tissue (BAT), liver, WAT, and skeletal muscle. Mice treated with garlic maintained a significantly higher body temperature than untreated mice during a 6-h, 4°C cold challenge and, notably, AMP-activated protein kinase (AMPK) activity was stimulated in BAT, liver, WAT, and skeletal muscle. These results suggest that the antiobesity effects of garlic were at least partially mediated via activation of AMPK, increased thermogenesis, and decreased expression of multiple genes involved in adipogenesis.

Cardiovascular disease (CVD) is one of the main causes of mortality worldwide, and dyslipidemia is a major risk factor for CVD. Ginseng has been widely used in the clinic to treat CVD. Ginsenoside Rg3, one of the major active components of ginseng, has been reported to exhibit antiobesity, antidiabetic, and cardioprotective effects. However, the effect of ginsenoside Rg3 on hepatic lipid metabolism remains unclear. Therefore, we investigated whether ginsenoside Rg3 would regulate hepatic lipid metabolism with AMP-activated protein kinase (AMPK) activation in HepG2 cells. Ginsenoside Rg3 significantly reduced hepatic cholesterol and triglyceride levels. Furthermore, ginsenoside Rg3 inhibited expression of sterol regulatory element binding protein-2 (SREBP-2) and 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGCR). Ginsenoside Rg3 increased activity of AMPK, a major regulator of energy metabolism. These results suggest that ginsenoside Rg3 reduces hepatic lipid accumulation with inhibition of SREBP-2 and HMGCR expression and stimulation of AMPK activity in HepG2 cells. Therefore, ginsenoside Rg3 may be beneficial as a food ingredient to lower the risk of CVD by regulating dyslipidemia.

Decreased mitochondrial number and dysfunction in skeletal muscle are associated with obesity and the progression of obesity-associated metabolic disorders. The specific aim of the current study was to investigate the effects of rutin on mitochondrial biogenesis in skeletal muscle of high-fat diet-induced obese rats. Supplementation with rutin reduced body weight and adipose tissue mass, despite equivalent energy intake (p < 0.05). Rutin significantly increased mitochondrial size and mitochondrial DNA (mtDNA) content as well as gene expression related to mitochondrial biogenesis, such as peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), nuclear respiratory factor-1 (NRF-1), transcription factor A (Tfam), and nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, sirtulin1 (SIRT1) in skeletal muscle (p < 0.05). Moreover, rutin consumption increased muscle adenosine monophosphate-activated protein kinase (AMPK) activity by 40% (p < 0.05). Taken together, these results suggested at least partial involvement of muscle mitochondria and AMPK activation in the rutin-mediated beneficial effect on obesity.

Changes in nutraceutical lipid components of rice at different degrees of millingThe concentrations of several nutraceutical lipid components [tocol (i.e. tocopherol 1 tocotrienol) phytosterol, g-oryzanol, octacosanol, and squalene] in milled rice and brown rice were determined. The lipid content decreased significantly (p ,0.05) as the degree of milling increased, as did the total tocol content. Significant differences (p ,0.05) were observed in the relative percentages of a-tocopherol, a-tocotrienol, and g-tocotrienol in brown rice and milled rice. b-Sitosterol was the most abundant sterol, representing 50-56% of the total sterol content of all samples analyzed. There were no significant differences in the relative percentages of the sterol isomers as the degree of milling increased. The concentrations of g-oryzanol, squalene, and octacosanol in rice decreased significantly (p ,0.05) as the degree of milling increased.

The aim of the present study was to evaluate the effects of green tea (-)-epigallocatechin-3-gallate (EGCG) on the depletion of accumulated fat in differentiated 3T3-L1 adipocytes. Intracellular lipid accumulation was decreased significantly after 24 h of incubation with 10 microm EGCG, while the viability of adipocytes was reported to be unaffected. Under the same experimental conditions, the amount of glycerol released from cells into the medium was increased by 10 microm EGCG. The level of mRNA in the 3T3-L1 adipocytes was analysed by quantitative real-time RT-PCR. EGCG notably increased the mRNA level of hormone sensitive lipase (HSL), which catalyses the rate-limiting stage in hydrolysis of stored triacylglycerol to monoacylglycerol and free fatty acids. In conclusion, the experiment produced results which showed that green tea EGCG effectively depleted fat accumulation via the stimulation of lipolysis and increased HSL gene expression in 3T3-L1 adipocytes. These results may relate to the mechanism by which EGCG modulates lipolysis in adipocytes.