1-Carbomethoxy-β-Carboline, Derived from Portulaca oleracea L., Ameliorates LPS-Mediated Inflammatory Response Associated with MAPK Signaling and Nuclear Translocation of NF-κB

Abstract

Portulaca oleracea is as a medicinal plant known for its neuroprotective, hepatoprotective, antidiabetic, antioxidant, anticancer, antimicrobial, antiulcerogenic, and anti-inflammatory activities. However, the specific active compounds responsible for the individual pharmacological effects of P. oleracea extract (95% EtOH) remain unknown. Here, we hypothesized that alkaloids, the most abundant constituents in P. oleracea extract, are responsible for its anti-inflammatory activity. We investigated the phytochemical substituents (compounds 1–22) using nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESI-MS) and screened their effects on NO production in lipopolysaccharide (LPS)-induced macrophages. Compound 20, 1-carbomethoxy-β-carboline, as an alkaloid structure, ameliorated nitric oxide (NO) production, inducible nitric oxide synthase (iNOS), and proinflammatory cytokines associated with the mitogen-activated protein kinase (MAPK) pathways, p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK). Subsequently, we observed that compound 20 suppressed nuclear translocation of nuclear factor κB (NF-κB) using immunocytochemistry. Moreover, we recently reported that compound 8, trans-N-feruloyl-3’, 7’-dimethoxytyramine, was originally purified from P. oleracea extracts. Our results suggest that 1-carbomethoxy-β-carboline, the most effective anti-inflammatory agent among alkaloids in the 95% EtOH extract of P. oleracea, was suppressing the MAPK pathway and nuclear translocation of NF-κB. Therefore, P. oleracea extracts and specifically 1-carbomethoxy-β-carboline may be novel therapeutic candidates for the treatment of inflammatory diseases associated with the activation of MAPKs and NF-κB.

Deubiquitinase Inhibitor b-AP15 Attenuated LPS-Induced Inflammation via Inhibiting ERK1/2, JNK, and NF-Kappa B

“…These showed the important roles of MAPK and NF-κB in anti-inflammation research. In fact, many studies have reported that the inhibition of MAPK or NF-kB activation suppressed LPS-induced inflammation in macrophages (Dong et al, 2019;Kim et al, 2019;Ma et al, 2019;Shin et al, 2019;Somensi et al, 2019;Tian et al, 2019). Similarly, here, we found that b-AP15 inhibited phosphorylation of ERK1/2 and JNK and suppressed inflammatory reactions in THP-1 and mouse peritoneal macrophages.…”

Anti-Inflammatory Activity of Diterpenoids fromCelastrus orbiculatusin Lipopolysaccharide-Stimulated RAW264.7 Cells

“…The whole cell lysate were extracted using a Cell Lysis Buffer (Cell Signaling Technology, Beverly, MA, USA). Immunoblot analysis was performed using a previously described method [ 34 ]. After transfer to nitrocellulose (NC) membrane, the blocking membrane with 5% skimmed milk powder was incubated overnight at 4°C with primary antibody, including anti-phospho-JNK (1 : 1000), anti-JNK (1 : 1000), anti-phospho-p38 (1 : 1000), anti-p38 (1 : 1000), anti-phospho-ERK (1 : 1000), anti-ERK (1 : 1000), anti-phospho-p65 (1 : 1000), anti-p65 (1 : 1000), anti-phospho-I κ B α (1 : 1000), anti- I κ B α (1 : 1000), anti-COX-2 (1 : 1000), anti-iNOS (1 : 1000), and anti- β -actin antibodies (Cell Signaling, Beverly, MA, USA).…”

“…Measurement of NO Contents and Cell Cytotoxicity. NO assay was carried out for measurements of NO release using a previously reported method [34]. Briefly, RAW264.7 cells were plated at 1 × 10 5 cell density in 96-well microplate and cultured for 24 h. Compounds (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) were pretreated with increasing dose concentrations (0.5, 1, 5, 10, 25, 50, and 100 μM) and then stimulated with LPS (1 μg/mL, Sigma-Aldrich, St. Louis, MO, USA) for 18 h. The mixture of cell supernatant (100 μL) and Griess reagent (1% sulfanilamide +0.1% N-(1-naphthyl)ethylenediamine (Sigma-Aldrich, St. Louis, MO, USA)) in 5% phosphoric acid was recorded at 550 nm using a microplate reader (Varioskan LUX, Thermo Fisher Scientific Inc., Waltham, MA, USA).…”

“…IC 50 values were calculated by nonlinear regression analysis as described previously [35]. RAW264.7 cell cytotoxicity was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay [34].…”

Anti-Inflammatory Activity of Extracts and Pure Compounds Derived from Plants via Modulation of Signaling Pathways, Especially PI3K/AKT in Macrophages

“…The NF-κB pathway and additionally ERK1/2 and JNK were inhibited by Aster incisus [ 109 ] and Fructus sophorae [ 110 ] extracts; ERK1/2 and p38 were attenuated by Hibiscus syriacus [ 111 ] and Rodgersia podophylla [ 112 ] extracts; JNK and p38 were decreased by Populus deltoides [ 113 ] and Xanthii fructus [ 114 ] extracts in macrophage cell lines. Furthermore, deoxynimbidiol and trinorditerpenoid, diterpenoids from Celastrus orbiculatus [ 115 ], torilin, a sesquiterpene obtained from Torilis japonica [ 96 ], shikonofuran E, a phenolic compound isolated from Onosma paniculatum [ 116 ], scandoside, an iridoid from Hedyotis diffusa [ 117 ], bellidifolin, a xanthone from Swertia chirayita [ 118 ], 1-carbomethoxy-β-carboline, an alkaloid from Portulaca oleracea [ 119 ] and strictosamide, an alkaloid from Nauclea officinalis [ 120 ] inhibited both NF-κB and MAPK signaling ( Figure 3 ).…”