A Leaf Methanolic Extract of Wercklea insignis Attenuates the Lipopolysaccharide-Induced Inflammatory Response by Blocking the NF-κB Signaling Pathway in RAW 264.7 Macrophages

Abstract

The biological activity of Wercklea insignis (WI) in inflammation and the underlying mechanisms of action of extracts of this plant are largely unknown. In the present study, we investigated the effects of a WI methanolic extract on lipopolysaccharide-stimulated inflammation in the mouse macrophage cell line, RAW 264.7. A WI methanolic extract significantly inhibited NO, PGE(2), IL-6, IL-1β, and TNF-α production in LPS-stimulated RAW 264.7 cells. Expression of iNOS, COX-2, IL-6, IL-1β, and TNF-α were suppressed by the extract at both the mRNA and protein levels in lipopolysaccharide (LPS)-stimulated cells. Additionally, the attenuation of inflammatory responses in RAW 264.7 cells by the WI extract was closely associated with suppression of phosphorylation of mitogen-activated protein kinase (MAPK) molecules, including ERK, JNK1/2, and p38 MAPK and translocation of the nuclear factor (NF)-κB p65 subunit into the nucleus. The effect of WI extract was investigated against carrageenan-induced paw edema in female (20-25 g). Our results collectively indicate that the WI extract inhibits LPS-induced inflammatory responses by blocking the NF-κB signaling pathway in macrophages, supporting use of the extract as a therapeutic anti-inflammatory treatment.

Amelioration of an LPS-induced inflammatory response using a methanolic extract of Lagerstroemia ovalifolia to suppress the activation of NF-κB in RAW264.7 macrophages

“…Many anti-inflammatory agents, such as a methanolic extract of Werklea insignis, exhibit their potency by suppressing NF-κB signaling (34). In particular, natural products targeting the NF-κB pathway are considered to be effective in treating inflammatory diseases due to the inhibition of one or more activation steps in the signaling pathway.…”

Berberine down-regulates the Th1/Th2 cytokine gene expression ratio in mouse primary splenocytes in the absence or presence of lipopolysaccharide in a preventive manner

“…Berberine storage in splenocytes may prevent and suppress LPSinduced pro-inflammatory cytokine secretions and gene expressions [32], via down-regulating nuclear factor (NF)-κB signaling which is one of the inflammation-related signaling pathway [33]. It was found that the attenuation of inflammatory responses in RAW 264.7 cells by certain plant extracts was closely associated with the suppression of phosphorylation in MAPK molecules, including ERK, JNK1/2, and p38 MAPK and translocation of NF-κB p65 subunit into the nucleus [34]. Unfortunately, berberine administration could not significantly inhibit but increase TNF-α relative expression fold in splenocytes in the repair model (Table 6).…”

Anti-Inflammatory Activities of Methanol Extract ofMastixia arboreaC.B. Clarke as to Mouse Macrophage and Paw Edema

“…17) In LPS-stimulated RAW264.7 macrophage cells, the MA extract inhibited iNOS and COX-2 expression by downregulating NF-B translocation to the nucleus (Fig. 4A) and the phosphorylation of MAPKs, including ERK and JNK (Fig.…”