Safflomin A: A novel chemical marker for Carthamus tinctorius L. (Safflower) monofloral honey.

Monofloral safflower honey (MSH), produced from nectar of the medicinal Carthamus tinctorius L., has been shown with excellent nutritional value and biological activity. However, current MSH authenticity verification is insufficient. Herein, we fully characterized MSH from a metabolomic perspective and proposed a chemical marker for its authentication. Using palynological analysis, we confirmed the botanical origin of MSH. Ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/Q-TOF-MS) was applied further to compare MSH/safflower components. MSH and safflowers shared 1297 tentatively identified compounds, of which safflomin A was identified as a reliable characteristic indicator. When applied to commercial non-safflower honeys, none tested safflomin A positive. Solid phase extraction coupled UHPLC/Q-TOF-MS method revealed the LOD and LOQ of safflomin A in MSH to be 0.006 and 0.02 mg/kg, respectively, with concentrations ranging from 0.86 to 3.91 mg/kg. Collectively, safflomin A can be applied as a chemical marker for fingerprinting the botanical origin of safflower honey.