Identification of Monomenthyl Succinate, Monomenthyl Glutarate, and Dimenthyl Glutarate in Nature by High Performance Liquid Chromatography-Tandem Mass Spectrometry

Menthol, menthone, and other natural compounds provide a cooling effect and a minty flavor and have found wide application in chewing gum and oral care products. Monomenthyl succinate, monomenthyl glutarate, and dimenthyl glutarate provide a cooling effect without the burning sensation associated with menthol. Additionally, because they do not have a distinct flavor, they can be used in applications other than mint flavors. Because these menthyl esters have not been reported in nature, we undertook to identify a natural source for these cooling compounds. Using high performance liquid chromatography-tandem mass spectrometry, monomenthyl succinate was identified in Lycium barbarum and Mentha piperita, and monomenthyl glutarate and dimenthyl glutarate were identified in Litchi chinesis. The identifications were based on the correlation of mass spectrometric and chromatographic retention time data for the menthyl esters in the extracts with authentic standards which resulted in a 99.980% confidence in the identifications. Keywords: Lycium barbarum; Mentha piperita; Litchi chinesis; monomenthyl succinate; monomenthyl glutarate; dimenthyl glutarate; high performance liquid chromatography-tandem mass spectrometry (LC/MS/MS); Nature Identical (NI)