Steam Explosion as a Green Pretreatment Strategy to Enhance Total Phenolics Release and Biological Activities in Potentilla discolor Bunge Stems

To efficiently, sustainably, and rapidly extract bioactive compounds, steam explosion (SE) technology was tried to use for the first time as a pretreatment of <i>Potentilla discolor</i> Bunge (PDB) stems. This study systematically investigated the effects of SE on stem structure, total phenolic content, composition and bioactivities. Macroscopic observation showed that SE-treated stems became darker and deeper in color. Microscopic analysis indicated a reduction in hemicellulose and lignin contents, while the basic skeletal structure remained intact, which facilitated the release of active compounds. This structural modification was directly linked to an enhancement in biological activity. Compared with the untreated group, total phenolic content in SE-treated stems increased 1.11-1.94 times. Correspondingly, antioxidant and hypoglycemic activities were enhanced by 1.35-7.19 times, demonstrating a clear relationship between the structural changes and the improved bioactivity. HPLC analysis showed specific changes in chemical composition, with increased levels of total phenolic content, particularly phenolic acids and flavonoids. Compositional analysis using Q Exactive HF LC-MS and standard comparison revealed that complex macromolecules, such as flavonoid glycosides and polyphenols, were hydrolyzed into smaller, more bioavailable molecules, such as quercetin. Overall, SE pretreatment represents a sustainable and effective approach for improving the extraction of bioactive compounds from PDB stems. These active compounds hold significant potential for applications in functional foods, nutraceuticals, and natural health products, offering an innovative strategy to enhance the bioavailability and bioactivity of plant-derived compounds.