Glucose-lowering effect of DLBS3233 is mediated through phosphorylation of tyrosine and upregulation of PPARγ and GLUT4 expression

BACKGROUND: DLBS3233 is a standardized extract combination containing Lagerstroemia speciosa and Cinnamomum burmannii. The effect of DLBS3233 on glucose uptake, adiponectin secretion, and insulin signaling was examined in this study. METHODS: 3T3 Swiss albino preadipocytes and adipocytes were used to investigate gene expression detected using the reverse transcription polymerase chain reaction method. Immunoblotting assay and in vitro glucose uptake assay were also carried out in the experiment. RESULTS: DLBS3233 was seen to increase phosphorylation at the tyrosine residue of the insulin receptor substrate. DLBS3233 was also found to enhance the expression of genes associated with increased insulin signaling and sensitivity, such as peroxisome proliferator-activated receptor gamma, phosphatidylinositol-3 kinase, Akt, and glucose transporter 4. In addition, glucose transporter 4 protein levels were seen to increase as a result of DLBS3233 administration. The combination of extracts also increased glucose uptake and adiponectin secretion, and decreased resistin secretion significantly relative to control cells. Moreover, DLBS3233 administered to insulin-resistant Wistar rats showed an ability to control blood sugar, insulin levels, and other lipoproteins, including high-density lipoprotein, low-density lipoprotein, triglycerides, and total cholesterol. CONCLUSION: DLBS3233, as a combination of herbal extracts, holds promise in the treatment of type 2 diabetes, and possibly also in prevention of the disease.