Anti-adipogenic effect of oat hull extract containing tricin on 3T3-L1 adipocytes

Abstract

Oat hull ethyl acetate extract (50μg/μL) significantly inhibited triglyceride accumulation in 3T3-L1 adipocytes without causing cytotoxicity. The major active compound in the extract was isolated and identified as 5,7,4′-trihydroxy-3′,5′-dimethoxyflavone, tricin by mass spectrometry and 1H and 13C NMR analyses. The tricin content in oat hull was approximately 18mg/kg dry weight, and tricin constituted 9.6% of the total phenolic compounds in oat hull extract. The treatment of 3T3-L1 cells either with extract or purified tricin resulted in decreased lipid accumulation. The extract significantly decreased the activity of glycerol-3-phosphate dyhydrogenase, a marker of adipocyte differentiation in a dose dependent manner. The expression of major transcription factors, such as peroxisome proliferator-activated receptor (PPAR)-γ, CCATT/enhancer binding protein-α (CEBP/α), sterol regulatory binding protein 1 (SREBP1) and fatty acid synthase (FAS) was also significantly suppressed by the extract. When commercial purified tricin was added to 3T3-L1 cells the expression of all transcription factors were significantly decreased as low as 1.5μg/μL treatment. These results suggest that oat hull extract containing tricin possesses anti-adipogeneic effect.