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. (C) 2020 Elsevier Ltd. All rights reserved.