Glucosyl Hesperidin Has an Anti-diabetic Effect in High-Fat Diet-Induced Obese Mice.

Glucosyl hesperidin (GH) is a water-soluble derivative of hesperidin, a citrus flavonoid. GH has various pharmacological effects, such as hypolipidemic and hypouricemic effects, and may therefore be a useful supplement or drug. In the present study, we evaluated the effects of long- and short-term intake of GH on hyperglycemia and macrophage infiltration into the adipose tissue of high-fat diet (HFD)-fed mice. Long-term (11-week) consumption of GH tended to reduce body weight and the fasting blood glucose concentration of the HFD-fed mice, and ameliorated glucose intolerance and insulin resistance, according to glucose and insulin tolerance tests. Additionally, although GH did not affect fat pad weight, it reduced HFD-induced macrophage infiltration into adipose tissue. Short-term (2-week) consumption of GH did not affect the HFD-induced increases in body weight or fasting blood glucose, and it did not ameliorate glucose intolerance or insulin resistance. However, short-term intake did reduce the HFD-induced macrophage infiltration and monocyte chemotactic protein 1 (MCP-1) expression in adipose tissue. Furthermore, hesperetin, which is an aglycone of GH, inhibited MCP-1 expression in 3T3-L1 adipocytes, 3T3-L1 adipocytes co-cultured with RAW264 macrophages, and tumor necrosis factor-α-treated 3T3-L1 adipocytes. The present findings suggest that daily consumption of GH may have preventive and/or therapeutic effects on obesity-related diseases, such as diabetes mellitus.

Naringenin suppresses neutrophil infiltration into adipose tissue in high-fat diet-induced obese mice.

Recruitment of immune cells to adipose tissue is altered dramatically in obesity, which results in chronic inflammation of the adipose tissue that leads to metabolic disorders, such as insulin resistance and type 2 diabetes mellitus. The regulation of immune cell infiltration into adipose tissue has prophylactic and therapeutic implications for obesity-related diseases. We previously showed that naringenin, a citrus flavonoid, suppressed macrophage infiltration into adipose tissue by inhibiting monocyte chemoattractant protein-1 (MCP-1) expression in the progression phase to high-fat diet (HFD)-induced obesity. In the current study, we evaluated the effects of naringenin on neutrophil infiltration into adipose tissue, because neutrophils also infiltrate into adipose tissue in the progression phase to obesity. Naringenin suppressed neutrophil infiltration into adipose tissue induced by the short-term (2 weeks) feeding of a HFD to mice. Naringenin tended to inhibit the HFD-induced expression of several chemokines, including MCP-1 and MCP-3, in adipose tissue. Naringenin also inhibited MCP-3 expression in 3T3-L1 adipocytes and a co-culture of 3T3-L1 adipocytes and RAW264 macrophages. However, naringenin did not affect the expression of macrophage inflammatory protein-2 (MIP-2), an important chemokine for neutrophil migration and activation, in macrophages or in a co-culture of adipocytes and macrophages. Our results suggest that naringenin suppresses neutrophil infiltration into adipose tissue via the regulation of MCP-3 expression and macrophage infiltration.

Naringenin interferes with the anti-diabetic actions of pioglitazone via pharmacodynamic interactions.

Pioglitazone is a peroxisome proliferator-activated receptor gamma (PPARγ) full agonist and useful for the treatment of type 2 diabetes mellitus. Naringenin is a citrus flavonoid with anti-inflammatory actions, which has been shown to prevent obesity-related diseases and to activate PPARγ. The aim of this study was to investigate whether dietary naringenin affects the actions of pioglitazone. We administered naringenin (100 mg/kg) and pioglitazone (10 mg/kg) to Tsumura Suzuki Obese Diabetes (TSOD) mice for 4 weeks and then conducted an oral glucose tolerance test. We found that oral administration of naringenin attenuated the hypoglycemic action of pioglitazone in TSOD mice. However, pioglitazone and naringenin did not affect fasting blood glucose levels, epididymal fat pad weight and body weight changes in this administration period. Pioglitazone suppressed expression of obesity-related adipokines such as tissue inhibitor of metalloproteinases-1 in adipose tissue of TSOD mice, but this effect was attenuated by naringenin. However, naringenin did not affect the pharmacokinetics of pioglitazone after single or repeated administration. Naringenin exhibited weak partial agonist activity in time-resolved fluorescence resonance energy transfer assay, but naringenin interfered with pioglitazone agonism, consistent with partial agonism. Our results suggest that it is advisable to avoid administering a combination of naringenin and pioglitazone.