Background: Rosmarinic acid (RA) is a natural substance that may be useful for treating diabetes mellitus. The present study investigated the effects of RA on glucose homeostasis and insulin regulation in rats with streptozocin (STZ)-induced type 1 diabetes or high-fat diet (HFD)-induced type 2 diabetes. Methods: Glucose homeostasis was determined using oral glucose tolerance tests and postprandial glucose tests, and insulin activity was evaluated using insulin tolerance tests and the homeostatic model assessment for insulin resistance. Additionally, the protein expression levels of PEPCK and GLUT4 were determined using Western blot analysis. Results: RA administration exerted a marked hypoglycemic effect on STZ-induced diabetic rats and enhanced glucose utilization and insulin sensitivity in HFD-fed diabetic rats. These effects of RA were dose-dependent. Meanwhile, RA administration reversed the STZ- and HFD-induced increase in PEPCK expression in the liver and the STZ- and HFD-induced decrease in GLUT4 expression in skeletal muscle. Conclusion: RA reduces hyperglycemia and ameliorates insulin sensitivity by decreasing PEPCK expression and increasing GLUT4 expression.

Oxidative stress is involved in cancer development. Hydrogen (H2) is a potent antioxidant and exhibits anti-inflammatory and potentially anticancer-like activities. This study aimed to investigate the role of H2 incombination with 5-fluorouracil (5-FU) in cancer treatment both in vitro and in vivo using the colon 26 cell line. The survival rate was determined using the Kaplan–Meier survival test, and cell viability was assessed using cell viability imaging kit and the MTT assay, and activation of the cell apoptosis pathway (Phosphorylated adenosine monophosphate activated protein kinase (p-AMPK), Apoptosis-inducing factor (AIF) and Caspase 3) were characterized by western blots. Hydrogen water administration improved the survival of mice with colon 26-induced cancer. Furthermore, hydrogen water enhanced cell apoptosis in cancer cells, resulting in a marked increase in the expression of p-AMPK, AIF and Caspase 3 in colon 26 cells. Hydrogen water also increased the inhibitory effect of 5-FU on colon 26 cells with spect to cell survival rate and anticancer functions. Additionally, high-content hydrogen water exhibited stronger antioxidative and anticancer activity than did the natural hydrogen water. In conclusion, high-content hydrogen water can inhibit colon cancer, particularly in combination with 5-fluorouracil.

The role of peroxisome proliferator-activated receptor delta (PPARδ) in the development of cardiomyopathy, which is widely observed in diabetic disorders, is likely because cardiomyocyte-restricted PPARδ deletion causes cardiac hypertrophy. Thus, we investigated the effect of hyperglycaemia-induced oxidative stress on the expression of cardiac PPARδ both in vivo and in vitro. We used male Wistar rats to examine the effect of hyperglycaemia on PPARδ expression in streptozotocin-induced diabetic rats, primary neonatal rat cardiomyocytes, and H9c2 embryonic rat cardiomyocytes. PPARδ mRNA (messenger ribonucleic acid) and protein levels were measured using northern and western blotting, respectively. The lipid deposition within the heart section was assessed by oil red O staining. The formation of reactive oxygen species (ROS) and changes in morphology, protein synthesis, and α-actinin content in hyperglycaemic cells were also examined. Inhibitors of ROS production or mitogen-activated protein kinase (MAPK) activation were employed to investigate the possible mechanisms. Cardiomyopathy induced in streptozotocin-diabetic rats was associated with a marked decrease in cardiac PPARδ expression. Also, ROS production, cell size, and protein synthesis were increased while PPARδ expression was reduced in cells exposed to hyperglycaemia in vitro. However, these glucose-induced changes were abolished in the presence of tiron or PD98059 (MEK/ERK inhibitor). Our results suggest that inhibitors of ROS production or MAPK activation are involved in reduction of cardiac PPARδ expression in response to hyperglycaemia.