Correlation analysis of flower color, antioxidant activity, and anthocyanin content in Pueraria montana (Lour.) Merr.

This study investigated the relationships among floral color phenotype, pigment content, antioxidant activity, and anthocyanin glycosides in Pueraria montana (Lour.) Merr.. Fully expanded white (MW) and purple flowers (MP) were analyzed for flower color parameters, pigment content, and antioxidant activity, and targeted anthocyanin metabolomics was employed to identify key anthocyanin glycosides associated with floral pigmentation, followed by correlation analysis. Results showed that pigment content was negatively correlated with L* (lightness) and b* values and positively correlated with a* and C* values, indicating that pigment accumulation decreased floral brightness while increasing color saturation. Purple flowers showed significantly higher antioxidant activity across all three assays than white flowers, and anthocyanin content was significantly positively correlated with antioxidant activity, indicating that anthocyanins are the principal active components. Eight key anthocyanin glycosides associated with flower coloration were identified. Among them, delphinidin-3,5-O-diglucoside, cyanidin-3,5-O-diglucoside, and malvidin-3,5-O-diglucoside were strongly correlated with both flower color and antioxidant activity. Delphinidin-derived anthocyanins played a dominant role in purple flower coloration and the enhancement of antioxidant activity. These findings clarify the contribution of anthocyanin glycosides to flower color formation in P. montana and their association with antioxidant activity, providing a theoretical basis for the development of natural pigments and functional products with high antioxidant capacity.