Arbutus unedo L., (Ericaceae) inhibits intestinal glucose absorption and improves glucose tolerance in rodents

Ethnopharmacological relevance: Arbutus unedo L., (Ericaceae) is one of the most traditional plants commonly used to treat diabetes in people living in Eastern Morocco region particularly in Taza and Beni Mellal. Aim of the study: The aim of the study was to find if there is a scientific support to the ethnopharmacological relevance use of Arbutus unedo L., roots bark (AU) to treat diabetes. Materials and methods: We studied the effects of crude aqueous extract of AU on intestinal glucose absorption using short-circuit current technique in vitro and oral glucose tolerance test in vivo. Results: The aqueous extract of AU (10 µg/mL to 1 mg/mL) induced concentration-dependent inhibition of sodium-dependent glucose transport across isolated mouse jejunum. The maximal inhibition was obtained with 1 mg/mL, which exhibited more than 80% of the Phloridzin inhibition with an IC 50 close to 216 µg/mL. A 6-week AU ingestion (2 g/(kg day)), improved oral glucose tolerance as efficiently as metformin (300 mg/(kg day)). Arbutus unedo L. and metformin also reduced body weight. Conclusions: Arbutus unedo L. roots bark aqueous extract directly inhibited the electrogenic intestinal absorption of glucose in vitro. In addition it improved oral glucose tolerance and lowered body weight in rats after chronic oral administration in vivo. These results add a scientific support to the ethnopharmacological relevance use of Arbutus unedo L. roots bark to treat diabetes.