Catalpol was tested for various disorders including diabetes mellitus. Numerous molecular mechanisms have emerged supporting its biological effects but with little information towards its insulin sensitizing effect. In this study, we have investigated its effect on skeletal muscle mitochondrial respiration and insulin signaling pathway. Type-2 diabetes (T2DM) was induced in male C57BL/6 by a high fat diet (60% Kcal) and streptozotocin (50 mg/kg, i.p.). Diabetic mice were orally administered with catalpol (100 and 200 mg/kg), metformin (200 mg/kg), and saline for four weeks. Fasting blood glucose (FBG), HbA1c, plasma insulin, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), oxygen consumption rate, gene (IRS-1, Akt, PI3k, AMPK, GLUT4, and PGC-1α) and protein (AMPK, GLUT4, and PPAR-γ) expression in muscle were measured. Catalpol (200 mg/kg) significantly (p < 0.05) reduced the FBG, HbA1C, HOMA_IR index, and AUC of OGTT whereas, improved the ITT slope. Gene (IRS-1, Akt, PI3k, GLUT4, AMPK, and PGC-1α) and protein (AMPK, p-AMPK, PPAR-γ and GLUT4) expressions, as well as augmented state-3 respiration, oxygen consumption rate, and citrate synthase activity in muscle was observed in catalpol treated mice. The antidiabetic activity of catalpol is credited with a marked improvement in insulin sensitivity and mitochondrial respiration through the insulin signaling pathway and AMPK/SIRT1/PGC-1α/PPAR-γ activation in the skeletal muscle of T2DM mice.

Despite significant medical advancement, nasopharyngeal carcinoma (NPC) remains one of the most difficult cancers to detect and treat where it continues to prevail especially among the Asian population. miRNAs could act as tumour suppressor genes or oncogenes in NPC. They play important roles in the pathogenesis of NPC by regulating specific target genes which are involved in various cellular processes and pathways. In particular, studies on miRNAs related to the Epstein Barr virus (EBV)-encoded latent membrane protein one (LMP1) and EBVmiRNA- BART miRNA confirmed the link between EBV and NPC. Both miRNA and its target genes could potentially be exploited for prognostic and therapeutic strategies. They are also important in predicting the sensitivity of NPC to radiotherapy and chemotherapy. The detection of stable circulating miRNAs in plasma of NPC patients has raised the potential of miRNAs as novel diagnostic markers. To conclude, understanding the roles of miRNA in NPC will identify ways to improve the management of patients with NPC.