Analysis of the Secondary Metabolites in Kadsura coccinea Fruit and Their Accumulation Difference in Peel, Pulp and Seed Organs

In order to explore Kadsura coccinea fruit development and utilization, widely-targeted metabolomics was used to identify the compounds in different organs of K. coccinea fruit, according to their structural distribution and categories, the diversity and abundance of the secondary metabolites were analyzed. Results: A total of 307 secondary metabolites were identified in the fruit of K. coccinea, among which phenolic acids (38.8%) and flavonoids (27.7%) were the dominant. In particular, 272 were found in the peel, 286 in the pulp, 201 in the seed, and 180 in all three parts. The amount of phenolic acids, flavonoids, and terpenoidswas significantly lower in seed than in pulp and peel, resulting in a lower diversity of secondary metabolites. The abundance of secondary metabolites in the peel (81.62×10⁷) was much higher than that in the pulp (25.61×10⁷) and seed (24.38×10⁷), mainly due to the high enrichment offlavonoids (quercetins, catechins and cyanidins) and the significant up-regulation of alkaloids. The metabolic components were mainly phenolic acids and flavonoids. The peel of K. coccinea was rich in flavonoids (quercetin, catechins and cyanidins, etc), and the seeds were rich in lignins. All three parts contained triterpenoids with novel structures, indicating that the fruit had significant utilization potential and research value.