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Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/26/2014 Publication Date: 1/26/2014 Citation: Zeller, W.E. 2014. Synthesis of 1-O-methylchlorogenic acid: reassignment of structure for MCGA3 isolated from bamboo (Phyllostachys edulis) leaves. Journal of Agricultural and Food Chemistry. 62:1860-1865. Interpretive Summary: Investigation of the benefits of substances isolated from plant material remains an important area of study in human food and health issues. Some of these substances have been implicated in the slowing or prevention of a variety of human diseases such as hypertention, inflammation, and cancer. 1-O-Methylchlorogenic acid, a substance isolated from bamboo leaves, shows promise in these disease areas in initial laboratory tests. Our interest in this substance stems from previous studies showing that substances of this type help in the preservation of utilizable protein in dairy forages during the ensiling process. 1-O-Methylchlorogenic acid is not available for purchase, and only small quantities can be obtained through the isolation procedure from bamboo leaves. Therefore, we developed a laboratory synthesis of 1-O-methylchlorogenic acid which is described in this paper. The synthetic sequence described here should be applicable to other scientists needing reasonable quantities of 1-O-methylchlorogenic acid and similar substances. The simple procedure for making 1-O-methylchlorogenic acid will help further research on understanding and utilizing this compound for both human and animal nutrition. Technical Abstract: The first synthesis of 1-O-methylchlorogenic acid is described. The short and efficient synthesis of this compound provides laboratory-scale quantities of the material to investigate its biological properties. The synthesis involved C-1 alkylation of the known (-)-4,5-cyclohexylidenequinic acid lactone followed by methoxide opening to the hydroxyl ester. Acylation of the C-5 hydroxyl group followed by sequential removal of protecting groups afforded 1-O-methylchlorogenic acid. The NMR spectroscopic characteristics of this compound did not coincide with those reported for the original isolation from bamboo (Phyllostachys edulis) leaves of the compound designated MCGA3. Comparison of the published spectroscopic data reported for MCGA3, with both reported literature values and spectroscopic data obtained from an authentic sample, lead to the conclusion that the compound isolated from bamboo (Phyllostachys edulis) leaves is instead methyl chlorogenate. |
