The effects of hydroxycinnamic acid derivatives on adiponectin secretion

Adiponectin is positively correlated with insulin sensitivity. Hydroxycinnamic acid derivatives (HADs), observed ubiquitously in plants, have some physiological functions. In this study, we investigated the effect of HADs on serum adiponectin concentrations in mice and on adiponectin secretion of 3T3-L1 adipocytes. In mice, serum adiponectin concentrations were increased by γ-oryzanol administration. CAPE, curcumin, and trans-ferulic acid markedly enhanced the adiponectin secretion of 3T3-L1 adipocytes, but not γ-oryzanol. To clarify the effects of γ-oryzanol in mice or the effects of HADs on the underlying mechanisms of adiponectin secretion, we further investigated the effect of HADs on adiponectin secretion in the NF- κB activation state. Although the adiponectin secretion was reduced in the presence of lipopolysaccharide plus TNF- α and IFN- γ, only γ-oryzanol supported the activity of adiponectin secretion under NF- κB activated condition. The results indicate that these HADs might regulate adiponectin secretion by the inhibition of NF- κB activation. HADs might be effective for ameliorating type 2 diabetes.