» Articles » PMID: 19111603

Echinacea Increases Arginase Activity and Has Anti-inflammatory Properties in RAW 264.7 Macrophage Cells, Indicative of Alternative Macrophage Activation

Overview
Date 2008 Dec 30
PMID 19111603
Citations 18
Authors
Affiliations
Soon will be listed here.
Abstract

Ethnopharmacological Relevance: The genus Echinacea is a popular herbal immunomodulator. Recent reports indicate that Echinacea products inhibit nitric oxide (NO) production in activated macrophages.

Aim Of The Study: In the present study we determined the inhibitory effects of alcohol extracts and individual fractions of alcohol extracts of Echinacea on NO production, and explored the mechanism underlying the pharmacological anti-inflammatory activity.

Materials And Methods: Alcohol extracts of three medicinal Echinacea species, Echinacea angustifolia, Echinacea pallida and Echinacea purpurea, were prepared using Soxhlet apparatus and fractionated using HPLC. NO production by LPS activated RAW 264.7 macrophage cells was measured using a Griess reagent and iNOS detected using immunoblotting. In addition, effects on arginase activity were measured in RAW 264.7 cells stimulated with 8-bromo-cAMP +/- LPS.

Results: Alcohol extracts of all three Echinacea species significantly inhibited NO production by lipopolysaccharide (LPS)-activated the RAW 264.7 macrophage cell line; among them Echinacea pallida was the most active. The Echinacea-mediated decrease in NO production was unlikely due to a direct scavenging of NO because the extracts did not directly inhibit NO released from an NO donor, sodium nitroprusside. An immunoblotting assay demonstrated that the extract of Echinacea pallida inhibited inducible nitric oxide synthase (iNOS) protein expression in LPS-treated macrophages. The enzymes iNOS and arginase metabolize a common substrate, l-arginine, but produce distinct biological effects. While iNOS is involved in inflammatory response and host defense, arginase participates actively in anti-inflammatory activation. Arginase activity of RAW 264.7 cells stimulated with 8-bromo-cAMP was significantly increased by alcohol extracts of all three Echinacea species. The polar fraction containing caffeic acid derivatives enhanced arginase activity, while the lipophilic fraction containing alkamides exhibited a potential of inhibiting NO production and iNOS expression.

Conclusions: These results suggest that the anti-inflammatory activity of Echinacea might be due to multiple active metabolites, which work together to switch macrophage activation from classical activation towards alternative activation.

Citing Articles

Phytochemistry, Mechanisms, and Preclinical Studies of Echinacea Extracts in Modulating Immune Responses to Bacterial and Viral Infections: A Comprehensive Review.

Ahmadi F Antibiotics (Basel). 2024; 13(10).

PMID: 39452214 PMC: 11504277. DOI: 10.3390/antibiotics13100947.


Polyphenolic Characterization and Anti-Inflammatory Effect of In Vitro Digested Extracts of L. Plant Parts in an Inflammatory Model of Human Colon Cells.

Avila-Galvez M, Gimenez-Bastida J, Karadeniz B, Romero-Reyes S, Espin J, Pelvan E Int J Mol Sci. 2024; 25(3).

PMID: 38339018 PMC: 10855148. DOI: 10.3390/ijms25031744.


Sitosterol-rich against 7-ketocholesterol and lipopolysaccharide-mediated atherogenic responses by modulating NF-ΚB/iNOS signalling pathway in macrophages.

Ravi S, Duraisamy P, Krishnan M, Martin L, Manikandan B, Ramar M 3 Biotech. 2023; 13(10):331.

PMID: 37670802 PMC: 10475456. DOI: 10.1007/s13205-023-03741-6.


Fractions Represent Promising Plant-Based Anti-Inflammatory Formulations.

Vieira S, Goncalves S, M F Goncalves V, Llaguno C, Macias F, Tiritan M Antioxidants (Basel). 2023; 12(2).

PMID: 36829986 PMC: 9952182. DOI: 10.3390/antiox12020425.


On the Bioactivity of Extracts to Modulate the Production of Inflammatory Mediators.

Vieira S, M F Goncalves V, Llaguno C, Macias F, Tiritan M, Reis R Int J Mol Sci. 2022; 23(21).

PMID: 36362404 PMC: 9659013. DOI: 10.3390/ijms232113616.


References
1.
MacMicking J, Xie Q, Nathan C . Nitric oxide and macrophage function. Annu Rev Immunol. 1997; 15:323-50. DOI: 10.1146/annurev.immunol.15.1.323. View

2.
Morris Jr S, Chen L . Differential regulation of arginases and inducible nitric oxide synthase in murine macrophage cells. Am J Physiol. 1998; 275(5):E740-7. DOI: 10.1152/ajpendo.1998.275.5.E740. View

3.
Chan M, Mattiacci J, Hwang H, Shah A, Fong D . Synergy between ethanol and grape polyphenols, quercetin, and resveratrol, in the inhibition of the inducible nitric oxide synthase pathway. Biochem Pharmacol. 2000; 60(10):1539-48. DOI: 10.1016/s0006-2952(00)00471-8. View

4.
Rousseau B, Tateya I, Lim X, Munoz-Del-Rio A, Bless D . Investigation of anti-hyaluronidase treatment on vocal fold wound healing. J Voice. 2005; 20(3):443-51. DOI: 10.1016/j.jvoice.2005.06.002. View

5.
Woelkart K, Koidl C, Grisold A, Gangemi J, Turner R, Marth E . Bioavailability and pharmacokinetics of alkamides from the roots of Echinacea angustifolia in humans. J Clin Pharmacol. 2005; 45(6):683-9. DOI: 10.1177/0091270004273493. View