Comparative evaluation of two Leaf types in Callicarpa Nudiflora Hook. & Arn. Based on Leaf phenotypes and Metabolomics

This study compared the phenotypic traits of two leaf types of Callicarpa nudiflora Hook. & Arn. and to explore the differences in their secondary metabolites using a broad-targeted metabolomics approach. We measured the leaf phenotypic traits of both large-leaf (DBC) and small-leaf (DSC) types using leaf area analysis software, protractors, and vernier calipers. Our analysis revealed significant differences in phenotypic traits such as leaf base angle, area, perimeter, length, apex angle, width, density, and thickness, except for the leaf shape index and the number of primary lateral veins. Utilizing Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS), we detected secondary metabolites in the dried leaves, identifying 652 secondary metabolites across 8 categories, with 206 differential components accounting for 31.6% of the total. Among the differential components, flavonoids (67 types) and phenolic acids (75 types) were predominant, with the DSC type showing a significantly higher relative content of 50 flavonoids, including notable compounds such as rutin, coumarin, and apigenin, compared to DBC. Moreover, a strong correlation was observed between between leaf phenotypic traits and phenolic acid components, whereas this correlation appeared weaker with flavonoid components. Our findings highlight significant differences exist in the leaf phenotypic traits and secondary metabolites between the two leaf types of Callicarpa nudiflora, suggesting that the small-leaf type showing greater potential for high-quality breeding compared to the large-leaf type. This provides a scientific basis for quality control, breeding, and production of this medicinal material.