Inhibitory effects of Shiso (Perilla frutescens) extracts on an increase of blood glucose level in rats

Abstract

Diabetes mellitus is considered to be one of the main life style diseases. As one of the treatment methods for post-prandial hyperglycemia in patients with diabetes, several a-glucosidase inhibitors that inhibit the absorption of glucose have been used clinically, with some mild and severe side effects. We prepared a Shiso (Perilla frutescens) -extract fraction containing a large quantity (>5% in weight) of the flavonoid rosmarinic acid. We studied the effects of this fraction in vitro and in vivo, in enzymolog-ical and physiological experiments, using rats with or without diabetes mellitus. Results indicated two diferent hypoglycemic activities, an a-glucosidase inhibitor and a glucose transport inhibitor, which are present at safe levels and which act at the level of the small intestine. This discovery will facilitate the use of Shiso-extract for the control of postprandial hyperglycemia in diabetes mellitus.