Integrative metabolomics and antioxidant activity uncovers the chemical basis of heartwood color and quality markers in Dalbergia odorifera

Dalbergia odorifera heartwood represents a valuable traditional Chinese medicine, and its quality is closely related to its color in traditional practices. However, the link between the color, chemical composition, and bioactivity of D. odorifera heartwood remains unclear. In this study, metabolomic analyses of volatile and non-volatile compounds were conducted on purple, red, and yellow heartwood using Gas Chromatography - Mass Spectrometry (GC-MS) and Ultra Performance Liquid Chromatography - Tandem Mass Spectrometry (UPLC-MS/MS). Distinct metabolic variations were observed among the different color groups. Trans -nerolidol and 10 flavonoids served as major markers of color variation. Quantitative methods for these key metabolites were established using GC-MS and Ultra Performance Liquid Chromatography - Diode Array Detector (UPLC-DAD). Antioxidant assays demonstrated that purple heartwood exhibited the strongest antioxidant activity, followed by red and yellow, with butin and luteolin identified as the principal contributors. These findings elucidate the metabolic basis of color differentiation and antioxidant potential in D. odorifera heartwood, providing a scientific foundation for its quality evaluation and pharmacodynamic material basis.