Food Science and Technology Research
Online ISSN : 1881-3984
Print ISSN : 1344-6606
ISSN-L : 1344-6606
Original papers
Green Rooibos Extract from Aspalathus linearis, and its Component, Aspalathin, Suppress Elevation of Blood Glucose Levels in Mice and Inhibit α-amylase and α-glucosidase Activities in vitro
Nana Mikami Junko TsujimuraAyumi SatoAkiko NarasadaMayumi ShigetaMotoshi KatoShuichi HataEri Hitomi
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2015 Volume 21 Issue 2 Pages 231-240


To evaluate the suppressive effects of green rooibos (Aspalathus linearis) unfermented tea on postprandial hyperglycemia, we orally administered four carbohydrates with or without green rooibos extract (GRE) and its major flavonoid aspalathin (Asp). GRE significantly suppressed the elevation of blood glucose levels after glucose, maltose, and starch intake. Asp also lowered the levels for all four carbohydrates. To clarify the mechanism underlying these results, we performed an intraperitoneal glucose tolerance test (IPGTT) and measured the ability of GRE and Asp to inhibit the activities of carbohydrate-hydrolyzing enzymes in vitro. In IPGTT, GRE and Asp did not show suppressive effects on blood glucose, while they dose-dependently inhibited the activities of α-glucosidase and α-amylase in vitro. These results showed that GRE and Asp suppress the elevation of blood glucose levels. It was indicated that these effects may result from the suppression of glucose absorption and the inhibition of carbohydrate-hydrolyzing enzyme activities by GRE and Asp.

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© 2015 by Japanese Society for Food Science and Technology
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