随着人们生活节奏的加快和生活水平的提高，以肉类为主导的饮食方式日益普遍，由此引发的动脉粥样硬化和肥胖等代谢综合症已成为必须重视的健康主题。最近研究证明，红肉饮食后，肠道菌群代谢其中的左旋肉碱（L-Carnitine)，生成三甲胺（TMA）,三甲胺经肝脏氧化后生成氧化三甲基胺（TMAO）， TMAO 是诱发动脉粥样硬化的独立因素，针对性地开发有效控制TMAO产生的保健手段是当务之急。我们预实验发现药食两用食材-陈皮及其主要活性成分陈皮黄酮可以改变肠道菌群的构成、降低血液中的TMAO水平和减轻体重。因此本项目拟利用已建立的陈皮黄酮分析分离体系及生物活性发现平台，用左旋肉碱喂食小鼠模拟食肉饮食，探讨陈皮及其黄酮组分如何与肠道菌群相互作用，以及这种相互作用模式对TMAO产生的影响，从而在理论上揭示陈皮及其功能组分预防动脉粥样硬化的机理，为基于陈皮及其活性成分为基础的补充膳食开发提供依据。

Recent research has proved that human microbiota can metabolize L-carnitine, existing in red meat, to trimethylamine (TMA), which in turn is oxidized to trimethylamine oxide (TMAO) by liver enzyme flavin-containing monooxygenases (FMOs). TMAO has been shown to promote atherosclerosis and subsequent development of heart disease. Antibiotics has shown effective inhibition of TMA and TMAO production in vivo, however, they have much detrimental property for long term usage. Therefore, it is important and pivotal to explore the mechanism of inhibiting TMAO production in human microbiota with food components, which will serve as a foundation for further research and exploration in functional foods. The aim of this study is to investigate the inhibition mechanism of TMA and TMAO in mice microbiota by nobiletin and aged-tangerine peels, which contain multiple polymethoxyflavones and nobiletin is a major representative. We will use a C57BL/6 male mouse model feeding with L-carnitine to mimic the diet of ominivores to induce the elevated TMA and TMAO levels in vivo. Then we will attempt to inhibit the production of TMA and TMAO in mouse microbiota with nobiletin and citrus peel flavonoids to establish the mechanism based relationship between microbiota adjustment and functional food ingredients. We will also study the details of microbiota environment changes caused by nobiletin and citrus peel flavonoids and to elucidate the mechanism of L-carnitine (red meat) induced TMA production in mouse microbiota including the study of the elevated oxidative potential in microbiota in L-carnitine challenged mice. The ultimate goal of this study is to prove the theory that food ingredients such as nobiletin and mixed flavonoids from aged tangerine peel can have adjustable effect on microbiota and also can further inhibit the production of TMA and TMAO from meat consumption to reduce and prevent the occurrence of heart disease such as atheroscerosis.