Dehydroabietic acid, a diterpene, improves diabetes and hyperlipidemia in obese diabetic KK-Ay mice.

Terpenoids, which are contained in a large number of dietary and herbal plants, have many biological effects. In this study, the effects of dehydroabietic acid (DAA), a diterpene, on glucose and lipid metabolism were examined using obese diabetic KK-Ay mice. We showed here that DAA treatment decreased not only plasma glucose and insulin levels but also plasma triglyceride (TG) and hepatic TG levels. To examine the mechanism underlying the effects of DAA, the production of inflammatory cytokines was measured. It was shown that the DAA treatment suppressed the production of monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNFalpha) (proinflammatory cytokines) and increased that of adiponectin (an anti-inflammatory cytokine). As a result of the changes in the production of inflammatory cytokines caused by the DAA treatment, the accumulation of macrophages in adipose tissues was reduced. These results indicate that treatment with DAA improves the levels of plasma glucose, plasma insulin, plasma TG, and hepatic TG through the decrease in the macrophage infiltration into adipose tissues, suggesting that DAA is a useful food-derived compound for treating obesity-related diseases.