Cytokine-Suppressive Activity of a Hydroxylated Alkylamide from Echinacea purpurea

Abstract

Echinacea purpurea has been widely used to treat upper respiratory tract infections. Bioassay-guided fractionation of hexane and ethanol extracts of this plant yielded 4[(2-methylbutyl)amino]-4-oxo-2-butenoic acid (1) and 8,11-dihidroxy-dodeca-2E,4E,9E-trienoic acid isobutylamide (2), both of which are new to Echinacea. Compound 2 suppressed the production of TNF-α from RAW 264.7 cells with an IC₅₀ value of 6.8 µM, while 1 was inactive. Neither compound showed cytotoxicity at concentrations up to 100 µM. These findings support a growing body of literature demonstrating that E. purpurea contains an array of compounds that suppress cytokine secretion by macrophage-type cells in vitro.

Key words

Echinacea purpurea - Asteraceae - alkylamides - alkamides - anti-inflammatory - tumor necrosis factor-α

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