Prevention of diet-induced obesity by dietary isomerized hop extract containing isohumulones, in rodents

Abstract

OBJECTIVE: Isomerized hop extract (IHE), which consists mainly of isohumulones and is required in the beer brewing process, was investigated for its effects on diet-induced obesity in two strains of mice. DESIGN: C57BL/6N and KK-A y mice were fed a standard or high-fat diet containing IHE and their body and tissue weights were measured at various time points. Oral glucose tolerance tests (OGTT) and insulin tolerance tests (ITT) were carried out in high-fat diet-fed C57BL/6N mice. The effects of IHE on intestinal lipid absorption were examined in Wistar rats using a plasma triacylglycerol assay after oral administration of a lipid emulsion. Fecal lipid levels were also measured in these animals after they were fed a high-fat diet containing IHE for 15 days. The effects of IHE on pancreatic lipase activity and the expression of genes involved in hepatic lipid metabolism were also examined using an in vitro assay and quantitative RT-PCR, respectively. RESULTS: Supplementation of high-fat-containing chow with IHE reduced body weight gain and improved glucose tolerance in our experimental mice. A reduction in body weight gain was also observed in C57BL/6N mice fed a standard diet containing IHE. Wistar rats fed a high-fat diet containing IHE showed reduced plasma triacylglycerol levels and an increase in their fecal lipid excretion. Similarly, their pancreatic lipase activity was inhibited and their elevation in plasma triacylglycerol levels seen after the oral administration of lipid emulsion was significantly suppressed. IHE-fed mice showed an increased expression in their lipid oxidation genes and a decreased expression in genes involved in triacylglycerol biosynthesis. CONCLUSION: The inhibition of intestinal dietary fat absorption may be the mechanism by which IHE induces its weightlowering effects in high-fat diet-fed mice. The modulatory effect of IHE on lipid metabolism may also, at least partly, be responsible for its beneficial effects on body weight gain. These results suggest that IHE may be helpful in humans in preventing diet-induced obesity and perhaps even metabolic syndrome, the latter of which is known to be associated with obesity.

Yamabushitake Mushroom (Hericium erinaceus) Improved Lipid Metabolism in Mice Fed a High-Fat Diet

“…Activators of PPAR, such as fibrates and isohumulones, lower body weight gain, retroperitoneal adipose tissue weight, plasma TG level, and hepatic TG content. 4,[14][15][16] We investigated to determine whether activation of PPAR is involved in the anti-obesity effects of Yamabushitake mushroom Mean values were significantly different from those of the control group: Ã p < 0:05; ÃÃ p < 0:01. Ppara, peroxisome proliferator-activated receptor (PPAR); Apoa1, apo A-I; Lpl, lipoprotein lipase; Slc27a1, fatty acid transport protein 1; Slc27a4, fatty acid transport protein 4; Acsl1, acyl-CoA synthetase long-chain family member 1; Acox1, palmitoyl acyl-CoA oxidase 1; Acadm, acyl-CoA dehydrogenase, medium chain; Acadl, acyl-CoA dehydrogenase, long-chain; Srebf1, sterol regulatory element binding factor 1; Fasn, fatty acid synthase; Acaca, acetyl-CoA carboxylase extracts in mice fed a high-fat diet.…”

Isohumulones from hops (Humulus lupulus) and their potential role in medical nutrition therapy

“…Subsequent studies reported by this Japanese group indicated that the hops-derived isohumulones reduced elevated triglycerides associated with insulin resistance, and raised HDL cholesterol levels while reducing liver fat stores in diabetic animal models [19,20]. In a companion study this same group reported that the administration of isohumulones prevented high fat diet-induced obesity in the C57BL/6N mouse model [21]. Nozawa et al also reported that dietary supplementation with isohumulones was found to reduce the production of the proinflammatory prostaglandin E 2 in the rat colon suggesting a tissue-specific anti-inflammtory effect [22].…”

Tetrahydro iso-Alpha Acids from Hops Improve Glucose Homeostasis and Reduce Body Weight Gain and Metabolic Endotoxemia in High-Fat Diet-Fed Mice

“…In addition to these effects hops-derived compounds (including iso -alpha acids) have been found to block TNF-α-induced production of IL-6 and to inhibit the transactivation of NF-κB, activator protein-1 (AP-1), and cAMP-response element-binding protein (CREB) in fibroblasts [17]. More recently, it has been proposed that hops has positive impact on adipocyte metabolism [18] and glucose tolerance in obese and diabetic rodents; however, the exact mechanisms explaining these effects are not well characterized [19], [20]. Therefore, in the present study we investigated the impact of a well-defined hop extract (META060) on body weight gain, fat mass development, glucose homeostasis and gut barrier function markers in diet-induced obese and type 2 diabetic mice.…”