immunomodulatory herbs: macrophage activation: Echinacea, cat's claw, saw palmetto

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The potency of immunomodulatory herbs may be primarily dependent upon

macrophage activation.

Groom SN, s T, Oldfield PR.

Department of Nutrition, McGill University, Montreal, Quebec, Canada.

J Med Food. 2007 Mar;10(1):73-9.

http://www.liebertonline.com/doi/pdfplus/10.1089/jmf.2006.233

Standardized extracts of Echinacea, cat's claw, and saw palmetto were

each evaluated for ability to activate macrophage and natural killer

cells, in vitro, using two independent measures of activation for each

immune cell population. A standard series of exposure concentrations

were tested for each herbal extract in a panel of four assays that

evaluated macrophage phagocytosis, macrophage synthesis of

interleukin-12, natural killer (NK) cell cytocidal activity (synthesis

of granzyme , and NK cell synthesis of interferon-gamma. Macrophage

phagocytosis was stimulated by all three herbs tested: saw palmetto (up

to 2.3-fold, P < .05), Echinacea (up to 3.6-fold, P < .01), and cat's

claw (up to 4.7-fold, P < .01). Additionally, NK cell synthesis of

interferon-gamma was stimulated by saw palmetto (up to 6.3-fold, P <

..01) and Echinacea (up to 8.1 fold, P < .01) but not by exposure to

cat's claw. None of the three herbs stimulated macrophage synthesis of

interleukin-12 or NK cell synthesis of granzyme B. Comparison of the in

vitro data with our earlier observations that cat's claw and Echinacea

(but not saw palmetto) were each effective in reducing B16/F10 lung

tumor colony formation in C57BL/6J mice suggests macrophage activation

is the primary means by which these herbs modulate the immune system.

Thus, macrophage activation (phagocytosis) may provide a potentially

higher throughput method to identify herbal extracts with in vivo

stimulatory effects.

PMID: 17472470

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