Exploring the Antidiabetic Properties of Polyalthia longifolia Leaf and Stem Extracts: In Vitro α-Glucosidase and Glycation Inhibition

<i>Polyalthia longifolia</i>, a member of the Annonaceae family, is traditionally used for its medicinal properties, including as an antidiabetic remedy, primarily in Asia and sub-Saharan Africa. This study investigated the potential of six <i>P. longifolia</i> extracts in counteracting hyperglycemia and diabetes-related complications. Aqueous, ethanol, and methanol extracts from leaves and stems were evaluated for their antihyperglycemic, antiglycation, and antiradical properties using α-glucosidase, BSA, and ORAC assays, respectively. Phytochemical characterization was conducted using TPC and TFC assays, and HPLC analysis identified specific bioactive compounds, including various phenolic compounds (gallic acid, (+)-catechin, epicatechin, caffeic acid, ellagic acid and rosmarinic acid) and flavonoids (luteolin, kaempferol and baicalein). The MTT assay on the human cell line HT-29 assessed the activity of extracts on cell viability, showing slight cytotoxicity. Results demonstrated significant antidiabetic activity of the ethanol and methanol extracts from <i>P. longifolia</i> leaves. This study provides new insights into the potential use of <i>P. longifolia</i> in diabetes mellitus and supports the valorization of traditional medicinal plants.