Ko Byoung-Seob, Jang Jin Sun, Hong Sang Mee, Sung So Ra, Lee Ji Eun, Lee Mi Young, Jeon Won Kyung, Park Sunmin
Deptartment of Quality Control and Inspection, Korea Institute of Oriental Medicine, Korea.
Biosci Biotechnol Biochem. 2007 Jun;71(6):1452-61. doi: 10.1271/bbb.60533.
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.
我们推测，炙甘草（甘草蜜炙品，GRP）可能因其成分变化而改变抗糖尿病作用。然后，我们研究了生甘草（GR）和GRP提取物及其主要成分甘草酸和甘草次酸的抗糖尿病作用及机制。在部分胰腺切除（Px）的糖尿病小鼠中，GR和GRP均改善了葡萄糖耐量，但只有GRP能像艾塞那肽-4一样增强葡萄糖刺激的胰岛素分泌。GR和GRP提取物均通过激活3T3-L1脂肪细胞中的过氧化物酶体增殖激活受体（PPAR）-γ增强胰岛素刺激的葡萄糖摄取。与小鼠研究结果一致，只有GRP和甘草次酸能增强分离胰岛中葡萄糖刺激的胰岛素分泌。此外，它们诱导胰岛中胰岛素受体底物-2、胰腺十二指肠同源盒-1和葡萄糖激酶的mRNA水平，这有助于提高β细胞活力。总之，含有甘草次酸的GRP提取物通过增强促胰岛素作用比GR提取物能更好地改善葡萄糖耐量。因此，GRP比GR具有更好的抗糖尿病作用。
