Laboratory of Pharmaceutical Analysis, Division of Pharmaceutical Chemistry, Faculty of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistiomiopolis, Zografou, 157 71 Athens, Greece.
Division of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, School of Health Sciences, National and Kapodistrian University of Athens, Panepistiomiopolis, Zografou, 157 71 Athens, Greece.
Talanta. 2018 Feb 1;178:246-257. doi: 10.1016/j.talanta.2017.09.029. Epub 2017 Sep 11.
Metabolic syndrome (MetS) represents a group of abnormalities that enhances the risk for cardiovascular disease, diabetes and stroke. The Mediterranean diet seems to be an important dietary pattern, which reduces the incidence of MetS. Hydroxytyrosol (HT) - a simple phenol found in olive oil - has received increased attention for its antioxidant activity. Recently, the European Foods Safety Authority (EFSA) claimed that dietary consumption of HT exhibits a protective role against cardiovascular disease. In this study, an experimental protocol has been setup, including isolated HT administration in a diet induced model of MetS in young Wistar rats, in order to find out whether HT has a protective effect against MetS. Rats were randomly divided into two groups nurtured by high-carbohydrate high-fat (H) (MetS inducing diet) and high-carbohydrate high-fat + HT (HHT). HT (20mg/kg/d oral gavage, water vehicle) was administered for 8 weeks on the basal diet. Previous pharmacological evaluation of HT showed that hepatic steatosis was reduced and the inflammatory cells into the liver were infiltrated. These indicate that HT shows bioactivity against metabolic syndrome. Therefore, the metabolomics evaluation of liver extracts would indicate the putative biochemical mechanisms of HT activity. Thus, the extracts of liver tissues were analyzed using Ultra Performance Liquid Chromatography - High Resolution Mass Spectrometry (UPLC-HRMS, Orbitrap Discovery) and Nuclear Magnetic Resonance (NMR) spectroscopy (Bruker Avance III 600MHz). Multivariate analysis was performed in order to gain insight on the metabolic effects of HT administration on the liver metabolome. Normalization employing multiple internal standards and Quality Control-based Robust LOESS (LOcally Estimated Scatterplot Smoothing) Signal Correction algorithm (QC-RLSC) was added in the processing pipeline to enhance the reliability of metabolomic analysis by reducing unwanted information. Experimentally, HHT rats were clearly distinguished from H in PLS-DA, showing differences in the liver metabolome between the groups and specific biomarkers were determined supporting the pharmacological findings. More specifically, HT has shown to be effective towards the mobilization of lipids as various lipid classes being differentially regulated between the H and HHT groups. Interestingly branched fatty acid esters of hydroxy oleic acids (OAHSA) lipids have been shown to be up regulated to the HHT group, denoting the alleviation of the MetS to the animals administered with HT.
代谢综合征（MetS）代表一组增加心血管疾病、糖尿病和中风风险的异常。地中海饮食似乎是一种重要的饮食模式，可以降低 MetS 的发病率。羟基酪醇（HT）——一种在橄榄油中发现的简单酚类物质——因其抗氧化活性而受到越来越多的关注。最近，欧洲食品安全局（EFSA）声称，膳食中 HT 的摄入对心血管疾病具有保护作用。在这项研究中，建立了一个实验方案，包括在年轻 Wistar 大鼠的 MetS 饮食诱导模型中单独给予 HT 饮食，以确定 HT 是否对 MetS 具有保护作用。大鼠随机分为两组，一组用高碳水化合物高脂肪（H）（MetS 诱导饮食）喂养，另一组用高碳水化合物高脂肪+HT（HHT）喂养。HT（20mg/kg/d 口服灌胃，水载体）在基础饮食上给药 8 周。HT 的先前药理学评价表明，HT 可减少肝脂肪变性和浸润肝脏的炎症细胞。这表明 HT 对代谢综合征具有生物活性。因此，对肝提取物的代谢组学评价将表明 HT 活性的潜在生化机制。因此，使用超高效液相色谱-高分辨率质谱（UPLC-HRMS，Orbitrap Discovery）和核磁共振（NMR）光谱（Bruker Avance III 600MHz）分析肝组织提取物。为了深入了解 HT 对肝脏代谢组的代谢作用，进行了多变量分析。采用多种内标物进行归一化，并添加基于质量控制的稳健局部估计散点平滑信号校正算法（QC-RLSC），通过减少不必要的信息，增强代谢组学分析的可靠性。实验中，HHT 大鼠在 PLS-DA 中明显与 H 区分开来，显示出两组之间的肝脏代谢组存在差异，并确定了特定的生物标志物，支持药理学发现。更具体地说，HT 已被证明可有效动员脂质，各种脂质类别的调节在 H 和 HHT 组之间存在差异。有趣的是，羟基油酸的支链脂肪酸酯（OAHSA）脂质被上调到 HHT 组，这表明 HT 减轻了动物的 MetS。
