Abstract:

Litchi water-soluble polysaccharide (LCWSP) was extracted from black leaf litchi through hot water extraction,
alcohol precipitation, centrifugation, and then bleached and deproteinized by Sevag’s method. After dialysis, LCWSP
was added to α-glucosidase solution and PNPG method was used to determine the activity of the enzyme. The results
showed that LCWSP had an obvious inhibition effect on α-glucosidase, which was 1.25 times as high as that of acarbose.
Optimal enzyme reaction parameters were determined by orthogonal array design based on single factor analysis. The
inhibitory effect of LCWSP was impacted by temperature, pH, time and polysaccharide concentration. The optimal
temperature, pH, reaction time and concentration for LCWSP inhibitory effect on α-glucosidase were 30 ℃, 6.8, 25 min and
80 mg/mL, respectively. LCWSP had an obvious inhibitory effect on α-glucosidase and could be used as an α-glucosidase
inhibitor. Meanwhile, LCWSP may have hypoglycemic effect, which provides a new direction for litchi processing and the
development of functional foods.

Key words: LCWSP；&alpha, -gucosidase inhibitor；activity