Alcohol extracts of Echinacea inhibit production of nitric oxide and tumor necrosis factor-alpha by macrophagesin vitro

Abstract

It has been suggested that Echinacea has anti-inflammatory activity in vivo. Nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), and interleukin-1beta are important mediators in the inflammatory response. The effect of alcohol extracts of E. angustifolia (EA), E. pallida (EPA) and E. purpurea (EP) on the production of these inflammatory mediators in both LPS-stimulated RAW 264.7 macrophages in vitro and murine peritoneal exudate cells (PECs) in vivo were investigated. As macrophages produce these inflammatory mediators in response to pathogenic infection, parallel cultures of macrophages were studied for phagocytosis and intracellular killing of Salmonella enterica. EPA and EP in vitro inhibited NO production and TNF-α release in a dose-dependent manner. RAW 264.7 cells treated with EA or EP showed decreased killing over 24 h, although EA enhanced bacterial phagocytosis. Upon bacterial infection, RAW 264.7 cells produce high levels of NO; however, an Echinacea-mediated decrease in NO production was observed. Echinacea alcohol extracts administered orally at 130 mg/kg per day for seven days had a weak effect on NO production and phagocytosis by LPS-stimulated PECs. The results indicated that all Echinacea species significantly decreased inflammatory mediators in vitro, however, only EA and EP reduced bacterial killing. Oral administration of Echinacea alcohol extracts did not adversely affect the development and anti-bacterial function of inflammatory PECs in vivo, however, NO production was decreased during bacterial infection of PECs.

Echinacea increases arginase activity and has anti-inflammatory properties in RAW 264.7 macrophage cells, indicative of alternative macrophage activation

“…However, improper upregulation of these inflammatory players are implicated in a pathological role in inflammatory processes (Yamamoto and Gaynor, 2001; Kiemer et al, 2002). Our results demonstrated the suppressive effects of Echinacea extracts and certain individual fractions on production of NO and TNF-α in an activated macrophage cell line, in accordance with previous in vitro observations (Chen et al, 2005; Matthias et al, 2007; Zhai et al, 2007a). In order to understand the cellular mechanism as well as the biological implication underlying the herbal anti-inflammatory activity, we carried out additional experiments.…”

“…Both alkamide-containing Echinacea extracts and purified alkamides inhibit production of proinflammatory tumor necrosis factor-alpha (TNF-α) and nitric oxide (NO) in an activated murine macrophage cell line (Chen et al, 2005; Matthias et al, 2007) with low cytotoxicity in vitro (Zhai et al, 2007a). Orally administered alcohol extracts of Echinacea significantly decreased production of TNF-α and interleukin (IL)-1βby activated splenocytes (Zhai et al, 2007b).…”

Caffeic acid derivatives, total phenols, antioxidant and antimutagenic activities of Echinacea purpurea flower extracts

“…This result is in agreement with the report of Zhai et al (2007). Several studies (Stuart & Wills, 2000;Wu et al, 2008) have shown that cichoric acid and other active ingredients in E. purpurea root are optimally extracted with 60% ethanol.…”

Echinacea for Treating the Common Cold

“…(10) Nevertheless, much of the foundational biomedical research on echinacea was done in Germany, where the plant was introduced in the 1920s, and used for a variety of illnesses, including respiratory infection. (11;12) Immunoactivity, including macrophage activation and cytokine expression, has been widely reported,(13–22) but specific pathways, pharmacokinetics, and mechanism of action of the various phytochemical constituents are incompletely understood. (23–29) Most commercially available echinacea products derive primarily from two species, Echinacea purpurea and E. angustifolia ,(30;31) and can be divided into two general categories.…”