Elucidating the Disparate Impact of Purification Levels on Lycium barbarum Phenolic Extracts: Chemical Composition...

Our study emphasizes the hypoglycemic potential of phenolic compounds extracted and purified from Lycium barbarum L. (L. barbarum) fruits. L. barbarum polyphenol extracts were purified using D101 macroporous resin, Sephadex LH-20 dextran gel, and C18 chromatographic column, with their α-amylase/α-glucosidase inhibitory activities assessed across purity grades. The results revealed 78 chemical components in the crude extract (C1), with 34 phenolic compounds identified after purification with macroporous resin (D1), and 25 phenolic compounds detected after further purification with Sephadex LH-20 gel (S1). Each purification step selectively altered the composition and content of the compounds, with substantial reductions observed in saponins and phenolic acids. Lycibarbarphenylpropanoid I (P1) was identified and characterized as a novel compound. Fraction C1 demonstrated the highest α-amylase inhibitory activity, while S1 exhibited the highest α-glucosidase inhibition. This suggests that different purification levels can enhance specific bioactivities responsible for hypoglycemic effects. The influence of various components on hypoglycemic enzyme activity varies significantly, suggesting the need for deeper exploration. This study presents critical insights into the phenolic extracts from L. barbarum fruits, and their hypoglycemic activity offers significant understanding of the application of these bioactive compounds.