Chen Ying, Xu Xiaomeng, Tang Chunping
University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
Molecules. 2025 Aug 1;30(15):3242. doi: 10.3390/molecules30153242.
Lotus ( Gaertn.) is a quintessential medicinal and edible plant, exhibiting marked differences in therapeutic effects among its various parts. The lotus seed constitutes a key component of this plant. Notably, the entire seed and the plumule display distinct medicinal properties. To investigate the "homologous plants with different effects" phenomenon in traditional Chinese medicine, this study established a Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI-MSI) method. This study employed immature lotus seeds as the experimental material, diverging from the mature seeds conventionally used. Conductive double-sided tape was employed for sample preparation, and complete longitudinal sections of the seeds were obtained, followed by MALDI-MSI analysis to identify and visualize the spatial distribution of characteristic secondary metabolites within the entire seeds. The results unveiled the diversity of metabolites in lotus seeds and their differential distribution across tissues, with pronounced distinctions in the plumule. A total of 152 metabolites spanning 13 categories were identified in lotus seeds, with 134, 89, 51, and 98 metabolites discerned in the pericarp, seed coat, cotyledon, and plumule, respectively. Strikingly, young lotus seeds were devoid of liensinine/isoliensinine and neferine, the dominant alkaloids of mature lotus seed plumule, revealing an early-stage alkaloid profile that sharply contrasts with the well-documented abundance found in mature seeds and has rarely been reported. We further propose a biosynthetic pathway to explain the presence of the detected benzylisoquinoline and the absence of the undetected bisbenzylisoquinoline alkaloids in this study. These findings present the first comprehensive metabolic atlas of immature lotus seeds, systematically exposing the pronounced chemical divergence from their mature counterparts, and thus lays a metabolomic foundation for dissecting the spatiotemporal mechanisms underlying the nutritional and medicinal value of lotus seeds.
莲（莲属）是一种典型的药食两用植物，其不同部位的治疗效果存在显著差异。莲子是这种植物的关键组成部分。值得注意的是，整个种子和莲子心表现出不同的药用特性。为了研究中药中的“同株异效”现象，本研究建立了基质辅助激光解吸/电离质谱成像（MALDI-MSI）方法。本研究采用未成熟莲子作为实验材料，与传统使用的成熟种子不同。使用导电双面胶带进行样品制备，获得种子的完整纵切面，然后进行MALDI-MSI分析，以识别和可视化整个种子内特征性次生代谢物的空间分布。结果揭示了莲子中代谢物的多样性及其在不同组织中的差异分布，莲子心中差异尤为明显。在莲子中总共鉴定出13类152种代谢物，在果皮、种皮、子叶和莲子心中分别识别出134种、89种、51种和98种代谢物。令人惊讶的是，未成熟莲子中没有莲心碱/异莲心碱和甲基莲心碱，而这些是成熟莲子心的主要生物碱，这表明早期生物碱谱与成熟种子中大量存在的情况形成鲜明对比，且鲜有报道。我们进一步提出了一条生物合成途径，以解释本研究中检测到的苄基异喹啉的存在以及未检测到的双苄基异喹啉生物碱的缺失。这些发现展示了未成熟莲子的首个全面代谢图谱，系统地揭示了其与成熟莲子明显的化学差异，从而为剖析莲子营养和药用价值的时空机制奠定了代谢组学基础。
