Carthamusuchuric acid, an enolic glucoside of phenylpyruvic acid from the florets of Carthamus tinctorius and anti-adipogenic phenolic compounds

Abstract A new unique enolic glucoside of phenylpyruvic acid, carthamusuchuric acid (1), and five known phenolic compounds (2–6) were isolated from the florets of Carthamus tinctorius. The structure of the new compound was elucidated by extensive spectroscopic analyses using one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy, high-resolution electrospray ionization mass spectrometry, and enzymatic hydrolysis. The anti-adipogenic activity of compounds 1–6 was evaluated by staining lipid droplets in 3T3-L1 preadipocytes with Oil Red O and assessing mRNA expression of adipocyte markers. The results showed that compounds 2 and 4 inhibited the differentiation of 3T3-L1 preadipocytes to adipocytes.