Identification and Characterization of Two New Derivatives of Chlorogenic Acids in Arnica (Arnica montana L.) Flowers by High-Performance Liquid Chromatography/Tandem Mass Spectrometry
journal contributionposted on 27.04.2011, 00:00 by Rakesh Jaiswal, Nikolai Kuhnert
Arnica montana is a medicinally important plant due to its broad health effects, and it is used in Ayurvedic, Homeopathic, Unani, and folk medicines. We have used LC−MSn (n = 2−5) to detect and characterize in Arnica flowers 11 quantitatively minor fumaric and methoxyoxalic acid-containing chlorogenic acids, nine of them not previously reported in nature. These comprise 1,5-dicaffeoyl-3-methoxyoxaloylquinic acid, 1,3-dicaffeoyl-4-methoxyoxaloylquinic acid, 3,5-dicaffeoyl-4-methoxyoxaloylquinic acid, and 1-methoxyoxaloyl-4,5-dicaffeoylquinic acid (Mr 602); 3-caffeoyl-4-feruloyl-5-methoxyoxaloylquinic acid and 3-feruloyl-4-methoxyoxaloyl-5-caffeoylquinic acid (Mr 616); 1,5-dicaffeoyl-4-fumaroyl and 1,5-dicaffeoyl-3-fumaroylquinic acid (Mr 614); 3,5-dicaffeoyl-1,4-dimethoxyoxaloylquinic acid (Mr 688); and 1-methoxyoxaloyl-3,4,5-tricaffeoylquinic acid and 1,3,4-tricaffeoyl-5-methoxyoxaloylquinic acid (Mr 764). All of the structures have been assigned on the basis of LC−MSn patterns of fragmentation, relative hydrophobicity, and analogy of fragmentation patterns if compared to caffeoylquinic acids. This is the first time when fumaric acid-containing chlorogenic acids are reported in nature.