A study to evaluate the effect of decreasing postprandial glucose levels of the botanical extract

INTERVENTION: Subjects will take the food containing botanical extract (1) once a day. After more than 5 days of washout period, subjects will take the beverage containing botanical extract (2) once a day. After more than 5 days of washout period, subjects will take the placebo beverage once a day. Subjects will take the beverage containing botanical extract (2) once a day. After more than 5 days of washout period, subjects will take the placebo beverage once a day. After more than 5 days of washout period, subjects will take the beverage containing botanical extract (1) once a day. Subjects will take the placebo beverage once a day. After more than 5 days of washout period, subjects will take the beverage containing botanical extract (1) once a day. After more than 5 days of washout period, subjects will take the beverage containing botanical extract (2) once a day. CONDITION: Not applicable PRIMARY OUTCOME: Efficacy : Area under the curve of blood glucose level. ; Safety : Incidence of adverse effects INCLUSION CRITERIA: 1. Males and females from 20 to 64 years of age 2. Understanding the study and submitting the written informed consent before the study