Diethyl Blechnic Exhibits Anti-Inflammatory and Antioxidative Activity via the TLR4/MyD88 Signaling Pathway in LPS-Stimulated RAW264.7 Cells

Abstract

Inflammation is a common pathogenesis in many diseases. Salvia miltiorrhiza Bunge (Danshen), a traditional Chinese medicine, has been considered to have good anti-inflammatory effects. In the present study, we investigated the anti-inflammatory effect of diethyl blechnic (DB), a novel compound isolated from Danshen, and its possible mechanisms in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. The results showed that DB can inhibit the LPS-induced pro-inflammatory cytokines release of prostaglandin E2 (PGE2) and mRNA expression of TNF-α, IL-6, and IL-1β. In addition, the results of the flow cytometry assay and the fluorometric intracellular ROS kit assay indicated that DB reduced the generation of ROS in LPS-stimualted RAW264.7 cells. DB reversed the LPS-induced loss of the mitochondrial membrane potential (MMP). Furthermore, DB suppressed the LPS-stimulated increased expression of Toll-like receptor 4 (TLR4), myeloid differential protein-88 (MyD88) and phosphorylation of TAK1, PI3K, and AKT. DB promoted NF-E2-related factor 2 (Nrf2) into the nucleus, increased the expression of heme oxygenase-1 (HO-1) and NAD(P)H dehydrogenase [quinone] 1 (NQO1) and reduced the expression of Keap1. In summary, DB may inhibit LPS-induced inflammation, which mainly occurs through TLR4/MyD88 and oxidative stress signaling pathways in RAW264.7 cells.

Native Chilean Berries Preservation and In Vitro Studies of a Polyphenol Highly Antioxidant Extract from Maqui as a Potential Agent against Inflammatory Diseases

“…In this study, we demonstrated that our extract (Ach) presented a protective activity against OS (DCF) on RAW 264.7 cells, along with the absence of cytotoxicity effect, in the same way as reported by Cespedes et al [24]. Moreover, it has been demonstrated that other natural products decrease intracellular ROS levels in LPS-stimulated macrophages [52,53], indicating the close relationship between oxidative mechanisms and inflammation. An experimental study published by Zhou et al [29] showed that the ethyl acetate fraction of maqui extract (MWE) contained a high content of total phenols and flavonoid and that exhibited stronger antioxidant activities than the other extracts such as n-butanol fraction.…”

Polysaccharide of Atractylodes Macrocephala Koidz(PAMK) Enhance the Immunomodulatory Activity of RAW264.7 Through TLR4/MyD88/NF-κB Pathway

“…These ndings were consistent with previous research. However, Zheng, He and Jun suggested that Diethyl Blechnic Exhibits, an inulin-type fructan from Codonopsis pilosula, a novel polysaccharide from Acorus tatarinowii could inhibit release of pro-in ammatory factors caused by LPS such as prostaglandin E2 (PGE2) and relative mRNA expression of TNF-α, IL-1β, IL-6 and myeloperoxidase (MPO) through TLR4/MyD88/NF-κB in RAW264.7 [30][31][32][33] . That also indicated that polysaccharide regulate RAW264.7 immune function by TLR4/MyD88/NF-κB signal pathway.…”

Rotundic acid reduces LPS‐induced acute lung injury in vitro and in vivo through regulating TLR4 dimer

“…According to a previous study (He et al, 2019), the cells were seeded into six-well plates overnight. The determination of NO and ROS levels was achieved by cell treatment with RA (0, 15, 30, 60 μM) for 1 h and subsequent stimulation with LPS for 8 h. In parallel, the determination of calcium was evaluated in macrophages treated with LPS for 4 h. Subsequently, the treated cells were hatched with 1 μM DAF-FM for 60 min, 1 μM DCFH 2 -DA for 30 min, and 1 μM Fluo-3AM for 60 min, respectively.…”

“…According to a previous study (He et al, 2019), the macrophages were seeded into culture dishes and cultured in an incubator for 14 h. Following treatment with RA (60 μM) and LPS, the extraction of cytoplasmic and nuclear proteins was carried out according to the kit scheme. The concentration of nuclear and cytoplasmic proteins was determined using the BCA protein kit.…”