Differential metabolome landscape of Kadsura coccinea fruit tissues and potential valorization of the peel and seed tissues

Kadsura coccinea (Lem.) is a woody wine plant with a peculiar fruit enriched in important health-promotingcompounds. The non-editable part of the fruit, i.e., the seed and peel, represents more than 60% of the fruit and isconsidered a biowaste. This significantly restricts the development of the K. coccinea fruit industry. Clarifying themetabolic components of the different fruit parts can help to improve the utilization rate and valorization ofK. coccinea. Herein, we evaluated K. coccinea fruit peel, pulp, and seed using widely-targeted metabolomics andquantified a set of 736 bioactive compounds from 11 major metabolite classes. The most prominent metabolite classesincluded lipids, amino acids, flavonoids, and lignans. Furthermore, our results emphasized a significant accumulationof flavonoids in pulp tissues, while alkaloids and lignans were abundant in peel and seed tissues, respectively. A totalof 183 metabolites were differentially accumulated among the three tissues. Procyanidin C2, rutinoside,2-hydroxyoleanolic acid, 5-hydroxymethyluracil, nootkatol, isoquercitrin, isohyperoside, quercetin-7-O-glucoside,hyperin, and rutin showed elevated accumulation in the peel. In the seed, kadsuralignan G, kadcoccilactone A,kadsuralignan H, lysoPE 20:5, iso-schisandrin ethyl alcohol, and kadangustin were significantly enriched. Our resultshighlight the diverse metabolome composition of K. coccinea fruit parts, which can be further exploited for itsvalorization in various industries.