Artocarpus lakoocha Roxb. and Oxyresveratrol Inhibits Interleukin 6 Secretion Related with Insulin Resistance in 3T3-L1 Adipocytes

Abstract

Chronic low-grade inflammation plays an important role in insulin resistance and the development of type 2 diabetes in obese people. Adipocytes, the most abundant cell type in adipose tissue, could produce various types of cytokines responsible for chronic inflammation. The purpose of the present study was to investigate the preventive effect of oxyresveratrol and Puag-Haad, which is the oxyresveratrol-enriched aqueous extract from Artocarpus lakoocha Roxb., on the inflammation and insulin resistance demonstrated by adipocytes. The release of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6, were monitored to evaluate the inflammatory status of the adipocyte cells during the 3T3-L1 adipocytes maturation period. Intracellular lipid accumulation and glucose uptake were measured to assess adipogenicity and insulin sensitivity status of mature adipocytes, respectively. The results showed that 3T3-L1 adipocytes substantially secreted IL-6 but not TNF-α, IL-1β. Further, IL-6 secretion was correlated with lipid quantity accumulated in the adipocytes. Oxyresveratrol and Puag-Haad predominantly exhibited anti-inflammatory activity in a dose-dependent manner, inhibiting IL-6 release but showed less effect on lipid accumulation. 3T3-L1 adipocytes treated with Puag-Haad (40 µg/mL) for 15 days showed significant decreases in fat accumulation and IL-6 secretion and promoted the glucose uptake. These outcomes indicate an improvement in insulin sensitivity. Taken all together, the data indicates that Puag-Haad is an interesting natural substance that should be further studied for its preventive effect on obese-mediated inflammation and the consequences of insulin resistance and type 2 diabetes. Keywords: Artocarpus lakoocha Roxb., Oxyresveratrol, Pro-inflammatory cytokine, Insulin resistance, Adipocyte