Instituto de Química, Universidade Federal de Goiás, Campus Samambaia, Goiânia, 74690-900, Goiás, Brazil.
Instituto de Ciências Biológicas, Universidade Federal de Goiás, Campus Samambaia, Goiânia, 74690-900, Goiás, Brazil.
Phytochem Anal. 2018 Jan;29(1):69-76. doi: 10.1002/pca.2715. Epub 2017 Sep 6.
Species of the genera Psychotria and Palicourea are sources of indole alkaloids, however, the distribution of alkaloids within the plants is not known. Analysing the spatial distribution using desorption electrospray ionisation mass spectrometry imaging (DESI-MSI) has become attractive due to its simplicity and high selectivity compared to traditional histochemical techniques.
To apply DESI-MSI to visualise the alkaloid distribution on the leaf surface of Psychotria prunifolia and Palicourea coriacea and to compare the distributions with HPLC-MS and histochemical analyses.
Based upon previous structure elucidation studies, four alkaloids targeted in this study were identified using high resolution mass spectrometry by direct infusion of plant extracts, and their distributions were imaged by DESI-MSI via tissue imprints on a porous Teflon surface. Relative quantitation of the four alkaloids was obtained by HPLC-MS/MS analysis performed using multiple-reaction monitoring (MRM) mode on a triple quadrupole mass spectrometer.
Alkaloids showed distinct distributions on the leaf surfaces. Prunifoleine was mainly present in the midrib, while 10-hydroxyisodeppeaninol was concentrated close to the petiole; a uniform distribution of 10-hydroxyantirhine was observed in the whole leaf of Psychotria prunifolia. The imprinted image from the Palicourea coriacea leaf also showed a homogeneous distribution of calycanthine throughout the leaf surface.
Different distributions were found for three alkaloids in Psychotria prunifolia, and the distributions found by MSI were in complete accordance with HPLC-MS analysis and histochemical results. The DESI-MSI technique was therefore demonstrated to provide reliable information about the spatial distribution of metabolites in plants. Copyright © 2017 John Wiley & Sons, Ltd.
Psychotria 和 Palicourea 属的物种是吲哚生物碱的来源，但植物体内生物碱的分布情况尚不清楚。与传统的组织化学技术相比，解吸电喷雾电离质谱成像（DESI-MSI）因其简单性和高选择性而成为一种有吸引力的分析方法。
应用 DESI-MSI 可视化 Psychotria prunifolia 和 Palicourea coriacea 叶片表面生物碱的分布，并将其与 HPLC-MS 和组织化学分析进行比较。
基于之前的结构解析研究，通过直接进样植物提取物，使用高分辨率质谱法鉴定了本研究中靶向的四种生物碱，并通过在多孔聚四氟乙烯表面进行组织印迹，使用 DESI-MSI 对其分布进行成像。通过三重四极杆质谱仪在多反应监测（MRM）模式下进行 HPLC-MS/MS 分析，获得四种生物碱的相对定量。
生物碱在叶片表面表现出明显的分布。Prunifoleine 主要存在于中脉，而 10-羟基异去甲育亨宾则集中在靠近叶柄的地方；在 Psychotria prunifolia 的整个叶片中观察到 10-羟基安替林均匀分布。从 Palicourea coriacea 叶片上的印痕图像也显示出整个叶片表面 calycanthine 的均匀分布。
在 Psychotria prunifolia 中发现了三种生物碱的不同分布，MSI 发现的分布与 HPLC-MS 分析和组织化学结果完全一致。因此，DESI-MSI 技术被证明能够提供有关植物代谢物空间分布的可靠信息。版权所有©2017 约翰威立父子公司
