UPLC-MS/MS Metabolomics Profiling of Differential Chemical Constituents and Blood-Absorbed Components Between Raw and Steamed Rhei Radix et Rhizoma
Processing-induced alterations in the material basis of Rhei Radix et Rhizoma were systematically interrogated using UPLC-MS/MS metabolomics coupled with multivariate statistical analysis. In vitro profiling of raw and steamed Rhei Radix et Rhizoma identified 201 constituents, comprising 45 anthraquinones, 43 tannins, 52 flavonoids, 21 stilbenes, 12 phenolic acids, 7 phenylpropanoids, 3 chromones, 2 aromatic aldehydes, and 16 miscellaneous compounds. Twenty-three components exhibited significant differential abundance (P < 0.05) following steaming: seven, including chrysophanol, gallic acid, and catechin, were significantly upregulated, whereas sixteen, including aloe-emodin-1-O-β-D-glucopyranoside, sennoside A, and proanthocyanidins, were significantly downregulated. Serum pharmacochemistry identified 94 migrated components, encompassing 36 prototype compounds and 58 metabolites, with 11 differential constituents detected in vivo between raw and steamed preparations. Steamed Rhei Radix et Rhizoma displayed elevated serum concentrations of select prototypes and metabolites, notably the tannin monomer gallic acid and phase-II anthraquinone metabolites, relative to the raw form. These findings demonstrate that steaming drives the conversion of bound anthraquinones to free aglycones, depolymerization of hydrolyzable tannins into monomeric units, and dynamic interconversion between condensed tannins and flavonoid aglycones. The processing-induced chemical transformation profile provides a mechanistic foundation for the differential therapeutic indications of raw versus steamed Rhei Radix et Rhizoma, supporting quality control strategies and clinical differentiation in purgative versus blood-activating applications.