Optimal extraction of a polysaccharide with antioxidant and hypoglycemic activities from the root of <i>Radix Puerariae lobatae</i> (Willd.) Ohwi

Radix Pueraria lobata has been recognized as a medicine and functional food, whose polysaccharide is its main bioactive component. In this study, we employed the response surface method to optimize the extraction of a polysaccharide from Radix Puerariae lobatae (PLP). Based on a single-factor experiment, three levels of liquid–material ratio, extraction time, and extraction temperature were selected for the response surface experiment. We established a quadratic regression equation of the extraction rate. The optimal combination conditions were obtained through regression analysis and ridge analysis. The optimal extraction yield of PLP was up to 5.526%, which was not significantly different from the verified value. Biologically, PLP1, a homogeneous P. lobatae polysaccharide isolated and purified from PLP, exhibited significant antioxidant and hypoglycemic properties in vitro. These findings provide an important foundation for the development and utilization of P. lobatae resources.