Endogenous levels of Echinacea alkylamides and ketones are important contributors to the inhibition of prostaglandin E2 and nitric oxide production in cultured macrophages.
Because of the popularity of Echinacea as a dietary supplement, researchers have been actively investigating which Echinacea constituent or groups of constituents are necessary for immune-modulating bioactivities. Our prior studies indicate that alkylamides may play an important role in the inhibition of prostaglandin E2 (PGE(2)) production. High-performance liquid chromatography fractionation, employed to elucidate interacting anti-inflammatory constituents from ethanol extracts of Echinacea purpurea, Echinacea angustifolia, Echinacea pallida, and Echinacea tennesseensis, identified fractions containing alkylamides and ketones as key anti-inflammatory contributors using lipopolysaccharide-induced PGE(2) production in RAW264.7 mouse macrophage cells. Nitric oxide (NO) production and parallel cytotoxicity screens were also employed to substantiate an anti-inflammatory response. E. pallida showed significant inhibition of PGE(2) with a first round fraction, containing gas chromatography-mass spectrometry (GC-MS) peaks for Bauer ketones 20, 21, 22, 23, and 24, with 23 and 24 identified as significant contributors to this PGE(2) inhibition. Chemically synthesized Bauer ketones 21 and 23 at 1 microM each significantly inhibited both PGE(2) and NO production. Three rounds of fractionation were produced from an E. angustifolia extract. GC-MS analysis identified the presence of Bauer ketone 23 in third round fraction 3D32 and Bauer alkylamide 11 making up 96% of third round fraction 3E40. Synthetic Bauer ketone 23 inhibited PGE(2) production to 83% of control, and synthetic Bauer alkylamide 11 significantly inhibited PGE(2) and NO production at the endogenous concentrations determined to be present in their respective fraction; thus, each constituent partially explained the in vitro anti-inflammatory activity of their respective fraction. From this study, two key contributors to the anti-inflammatory properties of E. angustifolia were identified as Bauer alkylamide 11 and Bauer ketone 23.
LaLone
Carlie A
CA
Center for Research on Dietary Botanical Supplements at Iowa State University, Iowa State University, Ames, Iowa 50011, USA.
Rizshsky
Ludmila
L
Hammer
Kimberly D P
KD
Wu
Lankun
L
Solco
Avery K S
AK
Yum
Manyu
M
Nikolau
Basil J
BJ
Wurtele
Eve S
ES
Murphy
Patricia A
PA
Kim
Meehye
M
Birt
Diane F
DF
D000577:Amides / Q000032:analysis* / Q000138:chemical synthesis / Q000494:pharmacology; D000818:Animals; D000893:Anti-Inflammatory Agents; D002460:Cell Line; D015232:Dinoprostone / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D020900:Echinacea / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D007659:Ketones / Q000032:analysis* / Q000138:chemical synthesis / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000037:antagonists & inhibitors* / Q000096:biosynthesis
D000577:Amides; D000893:Anti-Inflammatory Agents; D007659:Ketones; D009569:Nitric Oxide; D015232:Dinoprostone