We examined the effects of ginger and its effective components, zingerone and zingerol (reduced form of zingerone), on oxygen consumption (VO₂) and respiratory quotient (RQ) in rats fed a high-carbohydrate diet or a high-fat (lard) diet. Addition of 2% ginger powder to the high-carbohydrate and high-fat diets caused significant (approximately 7%) and insignificant (6%) increases, respectively, in 12-h cumulative VO₂ during the dark (feeding) period. The RQ values during the period were reduced significantly by the addition of ginger to both diets. Similar effects on VO₂ and RQ were also observed when, for comparison, 2% red pepper was added to the diets. We next examined the effects of zingerone, the major pungent component of ginger. Addition of 0.4% zingerone to the high-fat diet resulted in a marked increase in 12-h cumulative VO₂, a smaller increase in VO₂ being obtained by zingerone supplementation to the high-carbohydrate diet. The RQ values were also decreased by zingerone in both diet groups. On the other hand, addition of 0.4% zingerol, the non-pungent reduced form of zingerone, had little effect on VO₂ or RQ. However, when zingerone and zingerol were added simultaneously, the cumulative VO₂ was increased markedly and synergistically (about 30%) in both diet groups, with significant decreases in RQ. These results indicate that ginger and its pungent component zingerone have stimulatory action on energy expenditure by increasing oxygen consumption and accelerating the combustion of bodily fat.

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Seven cultivars of spinach (Spinacia olerancea L.)-Parade, Hoyo, Jiromaru, Orai, Orakuru, Okame, and Orion-were studied under the same fertilization and climatic conditions. Changes in the contents of reducing sugar, ascorbic acid, oxalate and nitrate in each cultivar were determined. The cultivars were all harvested 41 days after sowing. Hoyo, Jiromaru, and Orai were harvested again 7 days later (at day 48), Orakuru, Okame, and Orion were also harvested again 19 days later (at day 60). The contents of reducing sugar and ascorbic acid in the fast-growing Parade were lower than in the other cultivars. The ascorbic acid contents of Hoyo, Jiromaru, and Orai increased as the harvesting time was delayed. The nitrate content of Hoyo also increased. The amounts of ascorbic acid in Orakuru, Okame, and Orion were higher than those of other cultivars throughout the growing period until day 41. However, they did not show any increase when determined at the harvest time.

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Male Sprague-Dawley rats were fed a 0.2% cholesterol diet containing 20% casein (control group) or 15% casein and 5% black sea cucumber, as protein, for 4 weeks. Serum and hepatic cholesterol concentrations were significantly lower in rats fed black sea cucumber than in those fed a control diet. The ratio of HDL-cholesterol to total cholesterol was higher in the black sea cucumber group than in the control group. Fecal excretion of neutral and acidic steroids was stimulated by ingestion of black sea cucumber. These results suggest that black sea cucumber exerts a hypocholesterolemic effect by increasing the excretion of total steroids in feces.

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The effects of vanillylnonanamide-β-D-glucoside on lipid metabolism were studied in hyperlipidemic rats. Male Wistar rats weighing 280-290g were divided into three groups: a control group receiving a high-fat diet containing 1% cholesterol, and 0.003 and 0.03% glucoside groups receiving the high-fat diet supplemented with 0.003 and 0.03% vanillylnonanamide-β-D glucoside, respectively. All groups were fed ad libitum for 4 weeks. Both glucoside groups showed dose-dependent reductions in serum total cholesterol and triacylglycerol levels, and arteriosclerosis index in comparison with the control group. Their hepatic total lipid and triglyceride contents were also found to be lowered in a dose-dependent manner. Compared with the control group, hepatic cholesterol was lower and the fecal excretion rate of cholesterol was higher in the glucoside groups. In the 0.003% glucoside group, both acetyl-CoA carboxylase (ACC) [EC 6.4.1.2] and fatty acid synthase (FAS) activities were lower than in the other two groups. Hepatic triacylglycerol lipase (HTGL) [EC 3.1.1.3] activity was higher in the 0.03% glucoside group than in the other two groups. Lipoprotein lipase (LPL) [EC 3.1.1.34] activity and LPL mRNA abundance in adipose tissue were found to be higher in both the glucoside groups than in the control group. These results show that vanillylnonanamide-β-D-glucoside, with a slightly hot taste, has a lipid metabolism-improving effect comparable to that of capsaicin.

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