Abstract: Objective: This study aimed to investigate the in vitro probiotic properties of Lactobacillus plantarum Sc52 and its application in a hypoglycemic product and to analyze the hypoglycemic effect of the product. Methods: The in vitro probiotic properties of L. plantarum Sc52 were evaluated by its acid and bile salt tolerance, surface hydrophobicity and aggregation ability and minimum inhibitory concentration (MIC) of antibiotics against it. A mixed culture of L. plantarum Sc52 and other probiotics was used to ferment a composite aqueous extract of different both edible and medicinal plant materials to develop a solid beverage. In order to evaluate the hypoglycemic activity of the product, a diabetic mouse model was established by feeding high fat diet combined with streptozotocin injection. All the mice were divided into three groups: control, model and treatment groups. The mice in the treatment group were continuously administered with the solid beverage by gavage for four weeks. The levels of fasting blood glucose, the area under the blood glucose curve, the levels of serum lipids, insulin and inflammatory factor were measured. Results: L. plantarum Sc52 exhibited excellent resistance to acid and bile salt. When it was cultivated for 3 and 4 h in a medium at pH 3.0 with 1 g/100 mL bile salt concentration respectively, the survival rates were higher than 55% and 32%. L. plantarum Sc52 possessed strong aggregation ability, which reached (89 ± 0.3)% after standing for 48 h, and showed high sensitivity to penicillin and rifampicin. Compared with the model group, the auxiliary hypoglycemic product could significantly decrease the levels of fasting blood glucose, blood lipid and tumor necrosis factor-α and significantly elevate insulin levels. Conclusions: L. plantarum Sc52 exhibited good in vitro probiotic properties, and the solid beverage developed in this study had obvious hypoglycemic effects.

Key words: Lactobacillus plantarum, tolerance, adhesion, probiotic properties, hypoglycemic activity