Suppression of blood glucose level by a new fermented tea obtained by tea-rolling processing of loquat (Eriobotrya japonica) and green tea leaves in disaccharide-loaded Sprague-Dawley rats.
BACKGROUND
In the field of food science, much interest has been focused on the development of alternative medicinal foods with the ability to regulate excess blood glucose level (BGL) rise. The authors have successfully developed a new fermented tea product (LG tea) by co-fermentation of loquat (Eriobotrya japonica) leaf and summer-harvested green tea leaf. The objective of this study was to examine the acute suppression effect of LG tea on BGL rise in disaccharide-loaded Sprague-Dawley (SD) rats and to evaluate its possible usage as an antidiabetic functional food material.


RESULTS
As a result of single oral administration of hot water extract of LG tea (50 mg kg(-1)) to maltose-loaded SD rats, BGL at 30 min was significantly decreased by 23.8% (P < 0.01) compared with the control. A corresponding reduction in serum insulin secretion was also observed. The ED(50) value of LG tea (50.7 mg kg(-1)) was estimated to be about 16-fold higher than that of the therapeutic drug acarbose (3.1 mg kg(-1)).


CONCLUSIONS
No significant change in BGL was observed when sucrose or glucose was administered, suggesting that the suppression effect of LG tea was achieved by maltase inhibition, not by sucrase inhibition or glucose transport inhibition at the intestinal membrane.
Tamaya
Kei
K
Industrial Technology Center of Nagasaki, Ohmura, Nagasaki 856-0026, Japan. tamaya@tc.nagasaki.go.jp
Matsui
Toshiro
T
Toshima
Asami
A
Noguchi
Mai
M
Ju
Qiu
Q
Miyata
Yuji
Y
Tanaka
Takashi
T
Tanaka
Kazunari
K
D000818:Animals; D001628:Beverages; D001786:Blood Glucose / Q000032:analysis*; D003924:Diabetes Mellitus, Type 2 / Q000178:diet therapy; D031983:Eriobotrya; D005285:Fermentation; D005511:Food Handling; D055951:Functional Food; D005951:Glucose Tolerance Test; D006943:Hyperglycemia / Q000517:prevention & control; D007328:Insulin / Q000097:blood; D008297:Male; D008320:Maltose / Q000008:administration & dosage*; D018515:Plant Leaves; D019518:Postprandial Period; D051381:Rats; D017207:Rats, Sprague-Dawley; D013395:Sucrose / Q000008:administration & dosage; D013662:Tea; D013997:Time Factors
D001786:Blood Glucose; D007328:Insulin; D013662:Tea; D013395:Sucrose; D008320:Maltose