Aqueous Extracts of Liriope platyphylla Are Tightly-Regulated by Insulin Secretion from Pancreatic Islets and by Increased Glucose Uptake through Glucose Transporters Expressed in Liver Hepatocytes

Abstract

L. platyphylla is a perennial herb plant that is widely-distributed in temperate climate regions of the northern hemisphere. In Korea, these plants mainly grow mountainous regions at low altitude (i.e., <500 m sea level) and their leaves remain green year-round (Huh et al., 2007). L. platyphylla has been the basis of a traditional oriental herbal medicine that has been long-used for the treatment of asthma and bronchial and lung infl ammation (Lee et al., 2005). Data from several sciencebased studies has demonstrated the therapeutic effectiveness of the extract of the roots of L. platyphylla in the treatment of obesity, diabetes and neurodegenerative disease (Choi et al., Liriope platyphylla is a medical herb that has long been used in Korea and China to treat cough, sputum, neurodigenerative disorders, obesity and diabetes. The aims of this study were to study the antidiabetic effects of the aqueous extract of L. platyphylla (AEtLP) through pancreatic and extrapancreatic actions. AEtLP were orally administrated to ICR mice once a day for 7 days. Of three different concentrations of AEtLP, only 10% AEtLP were low toxic to liver, based on body weight and serum biochemical analyses. However, 10% AEtLP-treated mice displayed signifi cant reduction of the glucose concentration and increased insulin concentration; no changes were noted using 5% and 15% AEtLP. Also, the increase of glucose transporter (Glut)-1 expression in liver was dependent on the concentration of AEtLP, and was regulated by the phosphorylation of Akt. The lowest expression of Glut-3 was observed in 15% AEtLP treated mice, followed by 10% AEtLP-and 5% AEtLP-treated mice. This pattern of Glut-3 expression was roughly in accord with the phosphorylation of c-Jun N-teminal kinase (JNK) in the mitogen-activated protein kinase (MAPK) pathway. Furthermore, a signifi cant rise of the superoxide dismutase activity (SOD) was detected in AEtLP-treated mice. The fi ndings suggest that AEtLP should be considered as a diabetes therapeutic candidate to induce insulin secretion from pancreatic β-cells and glucose uptake in liver cells. Department of Experimental Animal Research, Clinical Research Institute, Seoul National University Hospital, 6 College of Pharmacy, Chungbuk National University, Chungju 361-763, Republic of Korea Abstract 2004;Hur et al., 2004;Jeong et al., 2008;Hur et al., 2009). Anti-infl amation and anti-microbial effects have been studied for a very long time. Kim et al. (2002) screened the extracts of many plants for anti-bacterial effects drugs via the detection of the inhibition of sortase (an enzyme found in most Gram-positive bacteria that is important in bacterial adhesion). Among 80 medical plants tested, L. platyphylla, Cocculus trilobus, Fritillaria verticillata, and Rhus vernicifl ua had strong anti-bacterial activity. Also, L. platyphylla potently inhibits airway infl ammation and hyperresponsiveness in a murine model of asthma by modulating the relationship between Th1/Th2 cytokine imbalance (Lee et al., 2005) as well as a...

Red Liriope platyphylla contains a large amount of polyphenolic compounds which stimulate insulin secretion and suppress fatty liver formation through the regulation of fatty acid oxidation in OLETF rats

“…Of these compounds, LP9M80-H induces insulin secretion and differentially regulates the expression of Glut-1 and Glut-3 expression through the mitogen-activated protein kinase (MAPK) and phosphoinisitide-3-kinase (PI3-K) signaling pathways (8). Furthermore, an aqueous extract of LP induces the upregulation of insulin secretion and the downregulation of glucose concentration through an increase in the expression of several Glut proteins regulated by the insulin signaling pathway (9).…”

Phytochemical and pharmacological overview on <i>Liriopes radix</i>

“…AEtLP dramatically decreased the abdominal fat mass and slightly decreased the glucose concentration [35], although no significant differences in body weight, glucose tolerance, and glucose concentration [36] in Otsuka Long-Evans Tokushima Fatty (OLETF) rats. AEtLP to ICR mice displayed a significant reduction of the glucose and increased insulin concentrations [37]. Significant alterations on serum adiponectin and lipid concentration [35,36] with GLUT-3, GLUT-1, JNK, and p38 pathway [35] and SOD expressions [37] were also reported.…”

“…AEtLP to ICR mice displayed a significant reduction of the glucose and increased insulin concentrations [37]. Significant alterations on serum adiponectin and lipid concentration [35,36] with GLUT-3, GLUT-1, JNK, and p38 pathway [35] and SOD expressions [37] were also reported. The insulin level was dramatically elevated upon co-treatment with high glucose and AEtLP in INS-1 cells may be tightly correlated with calcium regulation [38,39].…”

RedLiriope platyphyllastimulated the insulin secretion through the regulation of calcium concentration in rat insulinoma cells and animal models

“…Of these compounds, LP9M80-H dramatically induces insulin secretion and differentially regulates Glut-1 and Glut-3 expression through the mitogen-activated protein kinase (MAPK) and phosphoinisitide-3-kinase (PI3-K) signaling pathways [8]. Moreover, aqueous extracts of L. platyphylla were shown to induce insulin secretion from pancreatic islets as well as increase expression of glucose transporter in hepatocytes [9]. …”