Morimoto-Kobayashi Yumie, Ohara Kazuaki, Takahashi Chika, Kitao Sayoko, Wang Guanying, Taniguchi Yoshimasa, Katayama Mikio, Nagai Katsuya
Research Laboratories for Health Science & Food Technologies, KIRIN Company, Ltd., Yokohama, Kanagawa, Japan.
ANBAS Corporation, Osaka, Japan.
PLoS One. 2015 Jun 22;10(6):e0131042. doi: 10.1371/journal.pone.0131042. eCollection 2015.
Obesity is the principal symptom of metabolic syndrome, which refers to a group of risk factors that increase the likelihood of atherosclerosis. In recent decades there has been a sharp rise in the incidence of obesity throughout the developed world. Iso-α-acids, the bitter compounds derived from hops in beer, have been shown to prevent diet-induced obesity by increasing lipid oxidation in the liver and inhibition of lipid absorption from the intestine. Whereas the sharp bitterness induced by effective dose of iso-α-acids precludes their acceptance as a nutrient, matured hop bittering components (MHB) appear to be more agreeable. Therefore, we tested MHB for an effect on ameliorating diet-induced body fat accumulation in rodents. MHB ingestion had a beneficial effect but, compared to iso-α-acids and despite containing structurally similar compounds, acted via different mechanisms to reduce body fat accumulation. MHB supplementation significantly reduced body weight gain, epididymal white adipose tissue weight, and plasma non-esterified free fatty acid levels in diet-induced obese mice. We also found that uncoupling protein 1 (UCP1) expression in brown adipose tissue (BAT) was significantly increased in MHB-fed mice at both the mRNA and protein levels. In addition, MHB administration in rats induced the β-adrenergic signaling cascade, which is related to cAMP accumulation in BAT, suggesting that MHB could modulate sympathetic nerve activity innervating BAT (BAT-SNA). Indeed, single oral administration of MHB elevated BAT-SNA in rats, and this elevation was dissipated by subdiaphragmatic vagotomy. Single oral administration of MHB maintained BAT temperature at a significantly higher level than in control rats. Taken together, these findings indicate that MHB ameliorates diet-induced body fat accumulation, at least partly, by enhancing thermogenesis in BAT via BAT-SNA activation. Our data suggests that MHB is a useful tool for developing functional foods or beverages to counteract the accumulation of body fat.
肥胖是代谢综合征的主要症状，代谢综合征是指一组增加动脉粥样硬化风险的危险因素。近几十年来，肥胖在整个发达国家的发病率急剧上升。异α-酸是啤酒花中的苦味化合物，已被证明可通过增加肝脏中的脂质氧化和抑制肠道脂质吸收来预防饮食诱导的肥胖。然而，有效剂量的异α-酸所引起的强烈苦味使其难以被作为一种营养物质接受，而成熟啤酒花苦味成分（MHB）似乎更容易接受。因此，我们测试了MHB对改善啮齿动物饮食诱导的体脂积累的作用。摄入MHB有有益效果，但与异α-酸相比，尽管含有结构相似的化合物，其通过不同机制来减少体脂积累。补充MHB可显著降低饮食诱导的肥胖小鼠的体重增加、附睾白色脂肪组织重量和血浆非酯化游离脂肪酸水平。我们还发现，在喂食MHB的小鼠中，棕色脂肪组织（BAT）中解偶联蛋白1（UCP1）的mRNA和蛋白质水平均显著增加。此外，给大鼠施用MHB可诱导β-肾上腺素能信号级联反应，这与BAT中的cAMP积累有关，表明MHB可调节支配BAT的交感神经活动（BAT-SNA）。事实上，单次口服MHB可提高大鼠的BAT-SNA，而这种升高可通过膈下迷走神经切断术消除。单次口服MHB可使BAT温度维持在显著高于对照大鼠的水平。综上所述，这些发现表明，MHB至少部分地通过激活BAT-SNA增强BAT中的产热来改善饮食诱导的体脂积累。我们的数据表明，MHB是开发功能性食品或饮料以对抗体脂积累的有用工具。
