ABSTRACT Longan is an ancient and popular plant with highly nutritious fruit. The pulp is the main part of the fruit which is consumed. However, the potentials of other longan fruit parts such as the peel and the seed as reservoirs of important bioactive components have not yet fully been explored. This study aimed at exploring the diversity of primary and secondary metabolites in two commercial longan varieties, i.e., Shixia and Chuliang, concerning fruit, pulp, peel, and seed based on a widely targeted metabolomics approach. A total of 706 metabolites were identified grouped into eight diverse classes of metabolites, including flavonoids, amino acids and its derivatives, alkaloids, tannins, phenolic acids, organic acids, nucleotides and derivatives, lipids, and lignans. Chuliang peel showed a higher accumulation of metabolites viz. flavonoids, alkaloids, and tannins, while Shixia seeds showed abundance in amino acids, organic acid, nucleic acids and its derivatives. Chuliang pulp showed relatively higher accumulation of lipids when compared with other fruit parts. Differential metabolome profiling between fruit parts indicates the prevalence of key metabolites, i.e., O-Phosphocholine, betaine, piperidine, L-Arginine, and L-Phenylalanine, in seed and peel of the longan fruit. The findings in this research provide a new glance on the nutritional value and biochemical basis of longan fruit pharmaceutical value, with emphasis on valorization of longan peel and seed tissues for their pharmaceutical properties and nutritional values.

中文翻译：

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全面了解两个龙眼 (Dimocarpus longan Lour.) 品种的果肉、果皮和种子的代谢情况

摘要 龙眼是一种古老而受欢迎的植物，具有很高的营养价值。果肉是水果被消耗的主要部分。然而，其他龙眼果实部分（如果皮和种子）作为重要生物活性成分的储存库的潜力尚未得到充分探索。本研究旨在基于广泛靶向的代谢组学方法探索两个商业龙眼品种（即石夏和楚梁）在果实、果肉、果皮和种子方面的初级和次级代谢物的多样性。共鉴定出 706 种代谢物，分为八类不同的代谢物，包括黄酮类、氨基酸及其衍生物、生物碱、单宁、酚酸、有机酸、核苷酸及其衍生物、脂质和木脂素。楚良果皮表现出较高的代谢物积累，即。类黄酮，生物碱和单宁，而石夏种子则显示出丰富的氨基酸、有机酸、核酸及其衍生物。与其他果实部位相比，楚良果肉的脂质积累量相对较高。水果部分之间的差异代谢组分析表明关键代谢物，即 O-磷胆碱、甜菜碱、哌啶、L-精氨酸和 L-苯丙氨酸在龙眼果实的种子和果皮中的流行。本研究的发现为龙眼果实药用价值的营养价值和生化基础提供了新的视角，重点是龙眼果皮和种子组织的药用特性和营养价值。与其他果实部位相比，楚良果肉的脂质积累量相对较高。水果部分之间的差异代谢组分析表明关键代谢物，即 O-磷胆碱、甜菜碱、哌啶、L-精氨酸和 L-苯丙氨酸在龙眼果实的种子和果皮中的流行。本研究的发现为龙眼果实药用价值的营养价值和生化基础提供了新的视角，重点是龙眼果皮和种子组织的药用特性和营养价值。与其他果实部位相比，楚良果肉的脂质积累量相对较高。水果部分之间的差异代谢组分析表明关键代谢物，即 O-磷胆碱、甜菜碱、哌啶、L-精氨酸和 L-苯丙氨酸在龙眼果实的种子和果皮中的流行。本研究的发现为龙眼果实药用价值的营养价值和生化基础提供了新的视角，重点是龙眼果皮和种子组织的药用特性和营养价值。