• • Steaming significantly upregulated 7 constituents (P < 0.05), including chrysophanol, gallic acid, and catechin, while downregulating 16 constituents (P < 0.05), including aloe-emodin-1-O-β-D-glucopyranoside, sennoside A, and proanthocyanidins, among 201 identified compounds; this shift underpins the reduced purgative potency and enhanced blood-activating efficacy of steamed Rhei Radix et Rhizoma in clinical practice.
• • Serum pharmacochemistry identified 94 migrated components (36 prototypes, 58 metabolites) with 11 differential constituents between raw and steamed preparations; steamed Rhei Radix et Rhizoma showed elevated serum levels of gallic acid and phase-II anthraquinone metabolites, indicating enhanced glucuronidation and accelerated excretion of emodin and rhein, which mechanistically explains the attenuated hepatotoxicity observed after processing.
• • The conversion of bound anthraquinones to free aglycones in steamed Rhei Radix et Rhizoma increases the bioavailability of emodin and rhein, yielding a synergistic potentiation effect; this transformation supports the clinical preference for steamed Rhei Radix et Rhizoma in elderly, pediatric, and postpartum patients requiring purgation without severe depletion of vital qi.
• • Depolymerization of hydrolyzable tannins into monomeric gallic acid and dynamic interconversion between condensed tannins and flavonoid aglycones were observed, providing a chemical basis for the enhanced blood-activating and stasis-dissipating properties of steamed Rhei Radix et Rhizoma; these markers can serve as quality control indicators for processing standardization.