Hypoglycemic effect of aspalathin, a rooibos tea component from Aspalathus linearis, in type 2 diabetic model db/db mice.
Effects of aspalathin, a green rooibos tea component, on glucose metabolism were studied in vitro and in vivo. We first examined the effect of aspalathin on glucose uptake by cultured L6 myotubes and on insulin secretion from cultured RIN-5F pancreatic beta-cells in vitro, and then investigated the effect of dietary aspalathin on fasting blood glucose level and conducted an intraperitoneal glucose tolerance test (IPGTT) using type 2 diabetes model mice in vivo. Aspalathin dose-dependently and significantly increased glucose uptake by L6 myotubes at concentrations 1-100 microM. It also significantly increased insulin secretion from cultured RIN-5F cells at 100 microM. Dietary aspalathin (0.1-0.2%) suppressed the increase in fasting blood glucose levels of db/db mice for 5 weeks. In IPGTT, aspalathin improved impaired glucose tolerance at 30, 60, 90, and 120 min in db/db mice. These results suggest that aspalathin has beneficial effects on glucose homeostasis in type 2 diabetes through stimulating glucose uptake in muscle tissues and insulin secretion from pancreatic beta-cells.
Kawano
Atsutoshi
A
Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
Nakamura
Hiromichi
H
Hata
Shu-ichi
S
Minakawa
Miki
M
Miura
Yutaka
Y
Yagasaki
Kazumi
K
D000818:Animals; D036903:Aspalathus; D002478:Cells, Cultured; D047188:Chalcones / Q000494:pharmacology / Q000627:therapeutic use*; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D007004:Hypoglycemic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D013662:Tea
D047188:Chalcones; D007004:Hypoglycemic Agents; D007328:Insulin; D010936:Plant Extracts; D013662:Tea; C517016:aspalathin; D005947:Glucose