Comparison of The Anti-Inflammatory and Immunomodulatory Mechanisms of Two Medicinal Herbs: Meadowsweet (Filipendula ulmaria) and Harpagophytum (Harpagophytum procumbens)

Author(s): Juliette Cholet, Caroline Decombat, Marjolaine Vareille-Delarbre , Maël Gainche, Alexandre Berry, Clémence Ogéron, Isabelle Ripoche, Laetitia Delort, Marion Vermerie, Didier Frai

Background: Meadowsweet (Filipendula ulmaria) and Harpagophytum (H. procumbens) are two medicinal herbs traditionally used for their anti-inflammatory effect. Nonetheless, if the effects of the single compounds isolated from these plants have been well described, little is known about the molecular mechanisms behind whole extracts.

Methods: We studied and compared the effects of methanolic extracts from the aerial parts of F. ulmaria (FUE) and from the roots of H. procumbens (HPE) on different markers of inflammation such as antioxidant capacity, leukocyte ROS production, COX-2/PGE2 pathway or cytokine secretions.

Results: FUE proved to be better than HPE in terms of antioxidant capabilities. Even if their effect on COX-2/PGE2 were similar, we found that their immune-modulatory activities were quite different. In the basal state, the FUE favored cytokines associated with Th1 lymphocytes whereas the HPE decreased the secretion of IL-21 and IL-23, associated with Th17 cells. In PHA-stimulated cells, the HPE increased the characteristic cytokines of Th1 cells, whereas the effects of the FUE were more nuanced.

Conclusion: Though both plants are known as anti-inflammatory herbs, these results suggested that, apart from their similar anti-inflammatory effect on COX-2/PGE2, both could improve neutrophil and monocyte recruitment, as well as monocytes/macrophages and Th1, and presumably Th17, activation. Therefore, their impact on immune response was more likely immunostimulant.