Bioactive components and in vitro antioxidant and α-glucosidase inhibitory activities of Ulmus pumila

Ulmus pumila ( U. pumila ) is a widely distributed plant resource with important ecological value and a history of medicinal and edible use. However, the distribution of its bioactive components and associated biological activities across different plant parts and developmental stages remains insufficiently understood.In this study, aqueous extracts from the bark, leaves (at different developmental stages), and fruits of U. pumila were systematically investigated. UV–Vis and FT-IR spectroscopy, combined with standard colorimetric assays, were used to characterize major bioactive components, while antioxidant and α-glucosidase inhibitory activities were evaluated. In addition, a validated LC–MS/MS method based on 5 mmol/L ammonium acetate containing 0.1% formic acid–methanol was established for the simultaneous baseline separation and quantification of six representative phenolic compounds within 8 min. The bark exhibited the highest levels of total phenolics, flavonoids, and polysaccharides, as well as the strongest antioxidant and α-glucosidase inhibitory activities. Leaf extracts showed stage-dependent variation, with June leaves displaying higher antioxidant activity and October leaves showing stronger α-glucosidase inhibition. Total phenolics ranged from 15.336 to 29.854 mg GAE/g DW across samples. The LC–MS/MS method showed good linearity, precision, repeatability, and recovery. Six phenolic compounds were quantified, with chlorogenic acid as the predominant component (1.44–13.76 mg/g DW), followed by epicatechin and catechin. Correlation analysis indicated that phenolics and polysaccharides were significantly associated with antioxidant activity and α-glucosidase inhibitory capacity ( P < 0.01). These findings provide a comparative understanding of bioactive component distribution across plant parts and developmental stages of U. pumila . They also support its potential utilization as a natural source of bioactive compounds for agricultural and health-related applications.