Correlation between the composition and content of anthocyanins and leaf coloration in Nekemias grossedentataz,2

the raw material for processing vine tea. Purple vine tea holds market potential for diversifying products, yet the mechanism underlying purple leaf formation remains unclear. This study aimed to elucidate the relationship between anthocyanin profiles and leaf coloration in this species. Green leaves (LM1, LM2) exhibited higher total chlorophyll content (2.011–2.218 mg/g). Anthocyanins were identified as the dominant pigments for color, with total content in purple leaves (ZM1, ZM2, ZM3; 2322.31–7493.18 µg/g) significantly exceeding that in green leaves (166.11–1014.05 µg/g). A total of 81 anthocyanin components were putatively characterized, primarily containing derivatives of cyanidin, delphinidin, and peonidin (32, 10, and 10, respectively; MSI Level 2, see Fig. 10 legend). Distinct accumulation patterns were observed: ZM1 was enriched with cyanidin-3-O-glucoside (809.87 µg/g), ZM2 with malvidin-3,5-O-digucoside (1620.16 µg/g), and ZM3 with delphinidin-3,5-O-digucoside (1884.85 µg/g). OPLS-DA analysis identified cyanidin-3-O-glucoside, delphinidin-3-O-galactoside, delphinidin-3,5-O-digucoside, and petunidin-3-O-glucoside as key differential compounds. Correlation analysis revealed that the a* value is critical for hue distinction (positive in purple/reddish leaves, negative in green leaves). Total anthocyanin content showed a highly significant negative correlation with the L* value (lightness), while peonidin derivatives displayed a highly significant positive correlation with the a* value, identifying them as a key driver for purple coloration. This study clarifies the correlation between specific anthocyanins and color parameters in N. grossedentata leaves. The findings provide new insights into the biochemical mechanism of leaf color variation and offer a theoretical foundation for breeding new cultivars with diverse and desirable leaf color traits.