Abstract
Palmatine have been reported previously to effectively lower plasma glucose, increase antioxidants enzymes, protect the liver and kidney by modulating their disease markers, lower triglycerides and cholesterol in Streptozotocin induced diabetic rat model. Proteome study showed that Palmatine was differentially cause the expression of Lipid metabolizing, heat shock, antioxidant, calcium channels, glucose and fats metabolizing proteins. The protein-protein interaction and pathway confirms major interaction between the heat shock, antioxidant, channel and lipid metabolizing proteins. The aim of this study is to investigate the effect of Palmatine on insulin signaling pathway targeting IRS, IRS1, PI3K, PDK1, and GLUT4 Genes. Streptozotocin 45mg/kg was administered by intraperitoneal injection to induce diabetes in Sprague dawley rats. A week later rats with plasma glucose level of 200mg/dL and above were orally administered with palmatine (2mg/kg) for 90 days. The skeletal muscle and liver was extracted from the rats after 90 days treatment with Palmatine. RNA was isolated from the harvested tissue by homogening the tissue in 1 mL of trizol using mortar and pestle, incubated for five minutes at 25oC, 0.2mL of chloroform was added into the centrifuge tube containing the homogenized tissue. The tubes was vigorously shaken for fifteen minutes, incubated at 25oC and then centrifuged at 12000 x g for fifteen minutes at 7oC RNA was precipitated by mixing with 0.5 mL isopropyl alcohol incubating at 25oC for ten minutes and centrifuged at 12000 x g for ten minutes at 7oC. Pellet were recovered washed with 1 mL 75% ethanol, centrifuged at 7500 x g for five minutes at 7oC. Pellets were dissolved in 1 mL RNase-free water and incubated for ten minutes RNA purity was A260/280 ratio 2.0. cDNA synthesis was done using SensiFast cDNA Synthesis Kit the steps was according the supplier's instruction. qPCR and western blot were applied to analyze the expression of the genes. Palmatine was able to cause the phosphorylation of GLUT 4 through the activation IRS, IRS-1, PI3K, and therefore, increase the translocation of GLUT4 for glucose uptake. This result shows that the antidiabetic effect of palmatine maybe through the activation of the insulin pathway.
