Caffeic acids from roots of Arctium lappa and their neuroprotective activity / 中草药

ABSTRACT

Objective: To investigate the caffeic acid compounds from the roots of Arctium lappa and their neuroprotective activity. Methods: The compounds were isolated by column chromatography over silica gel, octadecylsilane (ODS) chemically bonded silica gel, Sephadex LH-20, and AB-8 macroporous resin coupled with preparative HPLC. Their structures were elucidated by spectroscopic analysis and their neuroprotective activity against glutamate-induced neurotoxicity was evaluated in SH-SY5Y cells by MTT assay. Results: Eight caffeic acid compounds were isolated from the roots of A. lappa, which were identified as 1,5-O-dicaffeoyl-3-O-(4-malic acid methyl ester)-quinicacid (1), 3,5-O-dicaffeoyl-quinic acid methyl ester (2), 3,4-O-dicaffeoyl-quinic acid methylester (3), 4,5-O-dicaffeoyl-quinic acid methyl ester (4), (2E)-1,4-dimethyl-2- [(4-hydroxyphenyl)methyl]-2-butenedioicacid (5), chlorogenic acid methyl ester (6), caffeic acid mtheyl ester (7), and 3,4,3',4'-tetrahydroxy-δ-truxinate (8). In vitro, these compounds showed the neuroprotective activity against glutamate-induced neurotoxicity on different levels. Conclusion: The neuroprotective activity of the roots in A. lappa against glutamate-induced neurotoxicity is related to the caffeic acid compounds. Compound 1 is a new compound; Compound 5 is a new natural compound; Compounds 2-4 and 6-7 are isolated from A. lappa for the first time; Compound 8 is isolated from the plants of Arctium L. for the first time.