Polar extract inhibits leptin release by adipose tissue derived from overweight and obese people

Abstract

Obesity escalates at an alarming rate worldwide. It is associated with chronic low-grade inflammation, which is implicated in the pathogenesis of type 2 diabetes and cardiovascular diseases. Adipose tissue is a primary site of obesity-induced pro-inflammatory factors such as leptin. Curcuminoids are potent anti-inflammatory agents; however, evidence on the polar fraction of Curcuma longa is scarce and the effect on leptin release has never been investigated. Therefore, we will investigate the influence of aqueous C. longa extract on leptin release from human subcutaneous adipose tissue (SAT). To achieve this, SAT explants were obtained from patients who underwent abdominal surgery. Patients were both males (67%) and females (33%). Their average body mass index (BMI) and age were 33.4 kg/m 2 and 43 years, respectively. Tissue explants were treated in triplicate with or without 0.1 and 1 mg/mL aqueous C. longa extracts and incubated for 24 and 48 h. Enzyme-linked immunosorbent assay (ELISA) was used to determine the concentration of leptin secreted by SAT. We have shown that 24 h treatment of SAT with 0.1 and 1 mg/mL of C. longa polar extract inhibited the release of leptin, while 48 h treatment of SAT with only 1 mg/mL of C. longa polar extract inhibited leptin release. Concentration of basal leptin released from SAT derived from females was higher than from males. However, this could be because females were morbidly obese. Our data demonstrate for the first time the inhibitory effect of aqueous C. longa extract on leptin release, shedding light on the role of leptin and adipose tissue in the mechanism of C. longa in reducing low-grade inflammation. This avoids the poor solubility and consequently the low bioavailability disadvantages of curcuminoids.