Stir-Frying Reshapes the Chemical Profile and Metabolic Effects of Raphani Semen in Diabetic Mice: Integrated Analysis of Hepatic Metabolism and Gut Microbiota

Stir-frying can alter the chemical composition and biological functionality of Raphani Semen (RS), but whether this processing improves its glucose-regulating properties remains unclear. In this study, a representative laboratory-scale stir-frying condition (160 °C for 3 min) was selected through exploratory chromatographic, macroscopic, and organoleptic assessment. Raw RS and stir-fried Raphani Semen (SF-RS) were subsequently compared using chemical and serum-exposure profiling, metabolic phenotyping, liver histopathology, hepatic proteomics and metabolomics, gut microbiota analysis, and targeted molecular validation in a diet/streptozotocin-induced mouse model of type 2 diabetes. Stir-frying altered relative LC-MS chemical response patterns and serum-detectable feature profiles, with selected glucosinolate-related signals showing the most consistent processing-associated differences. Functionally, SF-RS produced significantly greater reductions in terminal fasting glucose, insulin, and HOMA-IR than raw RS at all three matched doses (p < 0.05), while its advantage in OGTT AUC was particularly evident at the low dose. SF-RS also enhanced hepatic PAS-positive glycogen restoration across the tested dose range and improved lipid accumulation and collagen deposition at selected doses. Multi-omics analyses indicated processing-dependent regulation of PI3K–Akt/FoxO, PPAR, lipid, and cofactor metabolic pathways, together with distinct remodeling of the gut microbial community. Targeted validation further showed stronger regulation of PI3K-Akt signaling, Forkhead Box O1 (FoxO1) nuclear accumulation, and PPAR-α/CPT1A/ACOX1-associated fatty-acid metabolism after stir-frying. These findings indicate that thermal processing strengthens the glucose- and insulin-related functionality of Raphani Semen and enhances its potential value as a functional food ingredient for metabolic health.