Integrated serum pharmacochemistry-guided evaluation of Diyu Huanglian San against ethanol-induced gastric injury: involvement of kaempferol and PI3K/AKT signaling.

Diyu-Huanglian San (DYHLS) is a classical traditional Chinese herbal formula composed of Sanguisorba officinalis L. (Diyu), Coptis chinensis Franch. (Huanglian), Dolomiaea costus (Falc.) Kasana & A.K.Pandey (Muxiang), and Angelica sinensis (Oliv.) Diels (Danggui). It is traditionally indicated for gastrointestinal disorders characterized by damp-heat syndrome and mucosal damage. This study aimed to identify the bioavailable constituents of DYHLS and to clarify its protective mechanism against ethanol-induced gastric injury. Ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) was used to analyze the DYHLS extract and medicated serum. Network pharmacology, molecular docking, and molecular dynamics (MD) simulations were applied to screen the blood-absorbed constituents of DYHLS. Ethanol-induced gastric injury models in mice and human gastric epithelial GES-1 cells were established to evaluate its gastroprotective activity. Multiple indicators including ulcer index, histopathology, inflammatory cytokines, oxidative stress, apoptosis, and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway-related proteins were determined. Serum pharmacochemical analysis identified 24 blood-absorbed constituents of DYHLS, among which kaempferol exhibited the highest network connectivity. 83 candidate anti-ulcer targets were significantly enriched in the PI3K/AKT signaling pathway. Molecular docking and 100-ns MD simulations revealed strong and stable interactions between kaempferol and PI3K/AKT proteins. In mice, DYHLS and kaempferol effectively alleviated gastric injury, suppressed the release of inflammatory mediators, and reduced oxidative stress, while restoring antioxidant defenses. In GES-1 cells, kaempferol elevated cell viability and restrained inflammatory responses. Consistently, DYHLS and kaempferol modulated the PI3K/AKT pathway by regulating protein phosphorylation and the expression of anti-apoptotic proteins, thereby inhibiting cellular apoptosis. DYHLS protects against ethanol-induced gastric injury via coordinated anti-inflammatory, antioxidant, and anti-apoptotic effects, partly through kaempferol-mediated activation of PI3K/AKT signaling.