Monoterpene phenolic compound thymol promotes browning of 3T3-L1 adipocytes

• DOI: 10.1007/s00394-016-1273-2
• Publication Date: 2016-07-18T12:18:00Z
• Authors: Jae Heon Choi; Sang Woo Kim; Rina Yu; Jong Won Yun
• Keywords: Browning; Thymol; Lipogenesis; 3T3-L1; PRDM16

Appearance of brown-like adipocytes within white adipose tissue depots (browning) is associated with improved metabolic phenotypes, and thus a wide variety of dietary agents that contribute to browning of white adipocytes are being studied. The aim of this study was to assess the browning effect of thymol, a dietary monoterpene phenolic compound, in 3T3-L1 white adipocytes.Thymol-induced fat browning was investigated by determining expression levels of brown fat-specific genes and proteins by real-time RT-PCR and immunoblot analysis, respectively. Moreover, the molecular mechanism underlying the fat-browning effect of thymol was investigated by determining expression levels of key players responsible for browning in the presence of kinase inhibitors.Thymol promoted mitochondrial biogenesis and enhanced expression of a core set of brown fat-specific markers as well as increased protein levels of PPARγ, PPARδ, pAMPK, pACC, HSL, PLIN, CPT1, ACO, PGC-1α, and UCP1, suggesting its possible role in browning of white adipocytes, augmentation of lipolysis, fat oxidation, and thermogenesis, and reduction of lipogenesis. Increased expression of UCP1 and other brown fat-specific markers by thymol was tightly coordinated with activation of β3-AR as well as AMPK, PKA, and p38 MAPK.Our findings suggest that 3T3-L1 is a potential cell model for screening browning agents. Thymol plays multiple modulatory roles in the form of inducing the brown-like phenotype as well as enhancing lipid metabolism. Thus, thymol may be explored as a potentially promising food additive for prevention of obesity.