Changes in components, glycyrrhizin and glycyrrhetinic acid, in raw Glycyrrhiza uralensis Fisch, modify insulin sensitizing and insulinotropic actions.
We hypothesized that roasted Glycyrrhizae Radix (Glycyrrhizin Radix Praeparata, GRP) might modify anti-diabetic action due to compositional changes. Then we examined the anti-diabetic effect and mechanism of raw Glycyrrhizae Radix (GR) and GRP extracts and their major respective components, glycyrrhizin and glycyrrhetinic acid. In partial pancreatectomized (Px) diabetic mice, both GR and GRP improved glucose tolerance, but only GRP enhanced glucose-stimulated insulin secretion as much as exendin-4. Both GR and GRP extracts enhanced insulin-stimulated glucose uptake through peroxisome proliferation-activated receptor (PPAR)-gamma activation in 3T3-L1 adipocytes. Consistently with the results of the mice study, only GRP and glycyrrhetinic acid enhanced glucose-stimulated insulin secretion in isolated islets. In addition, they induced mRNA levels of insulin receptor substrate-2, pancreas duodenum homeobox-1, and glucokinase in the islets, which contributed to improving beta-cell viability. In conclusion, GRP extract containing glycyrrhetinic acid improved glucose tolerance better than GR extract by enhancing insulinotropic action. Thus, GRP had better anti-diabetic action than GR.
Ko
Byoung-Seob
BS
Deptartment of Quality Control and Inspection, Korea Institute of Oriental Medicine, Korea.
Jang
Jin Sun
JS
Hong
Sang Mee
SM
Sung
So Ra
SR
Lee
Ji Eun
JE
Lee
Mi Young
MY
Jeon
Won Kyung
WK
Park
Sunmin
S
D041721:3T3-L1 Cells; D017667:Adipocytes; D000818:Animals; D002470:Cell Survival; D003920:Diabetes Mellitus / Q000188:drug therapy*; D005786:Gene Expression Regulation / Q000187:drug effects; D005951:Glucose Tolerance Test; D006034:Glycyrrhetinic Acid / Q000494:pharmacology*; D029882:Glycyrrhiza uralensis / Q000737:chemistry*; D019695:Glycyrrhizic Acid / Q000494:pharmacology*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin; D050417:Insulin-Secreting Cells; D051379:Mice; D047495:PPAR gamma / Q000378:metabolism*
D007004:Hypoglycemic Agents; D007328:Insulin; D047495:PPAR gamma; D019695:Glycyrrhizic Acid; D006034:Glycyrrhetinic Acid