Hexane Extract of Citrus sphaerocarpa Suppresses the Accumulation of Lipid Droplets in 3T3-L1 Adipocytes

In this study, the hexane extract of Citrus sphaerocarpa (CSHE) was demonstrated in a dose-dependent manner to suppress the accumulation of lipid droplets in 3T3-L1 adipocytes. Furthermore, RNA-Seq analysis showed that CSHE treatment affected the expression of 1180 genes that are associated with adipocyte differentiation. Information on gene expression indicated that CSHE treatment may suppress adipogenesis because of the down- and upregulation of glycolysis/gluconeogenesis and β-oxidation, respectively, via insulin, PI3K/Akt, PKA/AMPK, and glucagon signaling pathways. In addition, the elution fraction of n-hexane/ethanol = 9:1 (v/v) from CSHE using silica gel column chromatography contained active components. Liquid chromatography/mass spectrometry (LC/MS) analysis of this fraction revealed the presence of polymethoxyflavones (PMFs) with hydroxyl groups. Based on previous reports, we hypothesize that hydroxylated PMFs have a particularly strong anti-obesity effect among the PMFs contained in citrus fruits.