The Potency of Immunomodulatory Herbs May Be Primarily Dependent upon Macrophage Activation

Abstract

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 B), 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.

The Inhibitory Effect of Echinacea purpurea and Echinacea pallida on BT-549 and Natural Killer Cells

“…16 The current study, however, supports an in vitro study that exposed NK cells to a series of concentrations of Echinacea and noted that cytotoxicity activity of the cells through the synthesis of granzyme B was not observed. 33 It supported another in vivo study that did not observe an altered NK cell activity in rats that were fed a commercial Echinacea product as well. 34 In all, in vitro studies of the effects of crude and water soluble extracts of E pallida leaf and E pallida root on BT-549 are needed.…”

Uncaria tomentosa stimulates the proliferation of myeloid progenitor cells

“…One of the possible pathways of action of Uncaria tomentosa is the prolongation of WBC survival due to the inhibited activation of NF-B (Sandoval et al, 2000;Fazio et al, 2008), which activates several different signals and can regulate the expression of several pro-inflammatory cytokines, including TNF-␣ (Groom et al, 2007), interleukin-1 (IL-1), interleukin-2 (IL-2), interleukin-6 (IL-6), and interleukin-8 (IL-8). These effects subsequently decrease oxidative stress (Pilarski et al, 2006) in the cell, which in turn reduces damage to DNA (Mammone et al, 2006).…”

Design and Evaluation of a Complex Phytoceutical Formulation for Circulatory Diseases

“…Due to: a) reduction of IL-2 production (Sasagawa et al, 2006); and b) downregulation of COX-2 expression (Groom et al, 2007). Immune-stimulant due to: a) macrophage phagocytosis stimulation (Raso et al, 2002); b) cellular immunity and neutrophils' phagocytosis stimulation.…”