Division of Pharmacognosy and Natural Products Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece.
Division of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece.
Phytochem Anal. 2022 Jan;33(1):83-93. doi: 10.1002/pca.3070. Epub 2021 Jun 6.
Nuclear magnetic resonance (NMR)-based metabolic profiling has been widely used in food and plant sciences. Despite its simplicity and inherent reproducibility, the determination of the appropriate pre-processing procedures greatly affects the obtained metabolic profile.
The current study represents a detailed guide of use for untargeted NMR-based metabolic profiling of table olives (Olea europaea L.).
Greek Kalamon table olives from different geographical origins were selected as reference materials. Differently treated samples were extracted using different solvents and/or solvent systems. Chemical profiles were evaluated with high-performance thin layer chromatography (HPTLC). Different deuterated solvents and sample concentrations were evaluated for the recording of optimal quality spectra.
The methanol extract of freeze-dried table olives was found to contain the most representative secondary metabolites, in higher concentrations, as well. The optimal deuterated solvent for the NMR analysis was methanol-d , while final sample concentration should be within the range of 10 to 15 mg/mL. Multivariate data analysis was also used to estimate and confirm the variation and clustering caused by different characteristics of the samples.
Results of the present study make evident the necessity for thorough planning and method development prior to any extensive metabolomic study based on NMR spectroscopy. Pre-processing and sample preparation stages seemed to greatly affect the metabolic profile and spectral quality in the case of table olives, which by extrapolation could apply to other food commodities. Nevertheless, the nature of the samples must be fully described in general, in order to proceed to solid conclusions.
基于核磁共振（NMR）的代谢组学分析已广泛应用于食品和植物科学领域。尽管 NMR 分析具有简单性和固有可重复性，但确定适当的预处理程序对获得的代谢谱有很大影响。
本研究详细介绍了基于 NMR 的橄榄（Olea europaea L.）代谢组学分析的使用方法。
选择来自不同地理起源的希腊卡拉蒙橄榄作为参考材料。采用不同的溶剂和/或溶剂系统对不同处理的样品进行提取。采用高效薄层色谱（HPTLC）评估化学图谱。评估了不同氘化溶剂和样品浓度，以记录最佳质量谱。
发现冻干橄榄的甲醇提取物含有更具代表性的次生代谢物，浓度也更高。用于 NMR 分析的最佳氘化溶剂是甲醇-d ，而最终样品浓度应在 10 至 15mg/mL 范围内。还使用多元数据分析来估计和确认由于样品的不同特性引起的变化和聚类。
本研究的结果表明，在基于 NMR 光谱的广泛代谢组学研究之前，需要进行彻底的规划和方法开发。预处理和样品制备阶段似乎对橄榄的代谢谱和光谱质量有很大影响，这可以推断适用于其他食品。然而，为了得出可靠的结论，必须全面描述样品的性质。
