Physicochemical Characterization and In Vitro Hypoglycemic Activity of a Low‐Molecular‐Weight Extracellular Polysaccharide From Deep‐Sea Beauveria bassiana

ABSTRACT Deep‐sea microorganisms constitute a valuable source of structurally diverse natural products. In this study, an extracellular polysaccharide was isolated from the deep‐sea fungus Beauveria bassiana T2‐2 by ultrasonic‐assisted hot water extraction followed by Sephadex LH‐20 chromatography, yielding a fraction designated BPS‐2. Physicochemical characterization revealed that BPS‐2 is a glucose‐rich polysaccharide (>90% molar ratio) with a weight‐average molecular weight of approximately 3.62 kDa and moderate levels of uronic acid (2.84%) and sulfate (3.15%). In vitro enzyme assays demonstrated that BPS‐2 inhibited α‐amylase and α‐glucosidase in a concentration‐dependent manner, with an IC 50 value of 1.3 × 10 −4 M for α‐glucosidase. Within the tested range, its inhibitory activity was stronger than that of Astragalus polysaccharide (APS) but weaker than that of acarbose. In a palmitic acid‐induced insulin‐resistant HepG2 model, BPS‐2 significantly enhanced glucose consumption and increased 2‐Deoxy‐2‐[(7‐nitro‐2,1,3‐benzoxadiazol‐4‐yl) amino]‐D‐glucose (2‐NBDG) uptake by 44.9% at 0.75 mg/mL without detectable cytotoxicity, suggesting a potential role in improving cellular glucose utilization under insulin‐resistant conditions. To the best of our knowledge, this is the first report describing hypoglycemic‐related activity of extracellular polysaccharides derived from deep‐sea B. bassiana . These findings provide initial evidence linking the structural features of BPS‐2 to glucose metabolism–associated bioactivity, while further studies are required to clarify detailed structural characteristics and underlying molecular mechanisms.