Abstract
INTRODUCTION: This study systematically evaluated the therapeutic potential of polysaccharides from the agricultural plant Orobanche cumana for diabetes management. METHODS: Three polysaccharide fractions (OCP-1, OCP-2, OCP-3) with distinct structural profiles were obtained through sequential extraction using water at room temperature, high-temperature water, and alkaline solution, respectively. RESULTS: Among them, the alkaline-extracted OCP-3 exhibited the most favorable properties, which was characterized as a rhamnogalacturonan-I-rich polysaccharide with a low molecular weight of 66,273 Da. OCP-3 demonstrated strong antioxidant activity by effectively scavenging 2,2-diphenyl-1-picrylhydrazyl, hydroxyl, and superoxide anion radicals, and significantly inhibited both α-amylase (IC₅₀ = 98.5 μg/mL) and α-glucosidase (IC₅₀ = 56.1 μg/mL). In streptozotocin-induced type 2 diabetic male C57BL/6 mice, OCP-3 treatment alleviated hyperglycemic symptoms, improved insulin sensitivity, and provided substantial protection against pancreatic, hepatic, and renal damage. Specifically, OCP-3 reduced fasting blood glucose from 31.3 to 17.2 mM and restored insulin levels to 10.34 mU/L, and improved oral glucose tolerance (AUC = 39.83 h·mmol/L), while maintaining an excellent safety profile in toxicological assessment. DISCUSSION: These findings not only validate the traditional use of Orobanche cumana but also establish OCP-3 as a safe and effective candidate for diabetes treatment, offering a sustainable approach to valorizing this agricultural plant.