Quantification of phenols in cinnamon: A special focus on “total phenols” and phenolic acids including DESI-Orbitrap MS detection

• Solvents and methods were tested for extraction of phenols from cinnamon.
• Total tissue disruption rather than solvent is needed for extraction of phenols.
• Powdered samples are comparable with simple extraction using mortar and pestle.
• Amount of phenolic acids depends on cinnamon type but free sinapic acid was not found.
• DESI-Orbitrap MS was successfully used for identification of phenolic acids in bark.

Despite its wide industrial use, quantitative data of phenolic compounds in cinnamon are scarce. Detailed investigation revealed that not solvent (water, 80% methanol, 60% ethanol) or cinnamon type but rather total tissue disruption (in mortar with pestle and inert sand or the extraction from powdered sample) is needed for maximal/“total” extraction as evidenced by “total soluble phenols” and cinnamic acid measurement. Cassia cinnamon contained higher amount of “total soluble phenols” and individual phenolic acids in the free fraction but Ceylon cinnamon in the cell wall-bound fraction. DESI-Orbitrap MS revealed no signal of sinapic acid by direct desorption from cinnamon bark: subsequent quantification of individual acids by LC–MS/MS confirmed 14 common phenolic acids but only traces of sinapic acid (μg/g) in the cell wall-bound fraction. We conclude that cinnamon does not contain more “total phenols” than known phenol-rich plant tissues and quantitative comparison with limited literature is performed in detail. It is urged that attention should be paid to state “the best extraction” and to identify individual phenols precisely.

Figure optionsDownload as PowerPoint slideImaging analysis of phenolic acids by DESI-Orbitrap MS in cassia cinnamon bark