Antiallergic Activity of Ethanol Extracts of Arctium lappa L. Undried Roots and Its Active Compound, Oleamide, in Regulating FcεRI-Mediated and MAPK Signaling in RBL-2H3 Cells

Abstract

The antiallergic potential of Arctium lappa L. was investigated in Sprague-Dawley rats, ICR mice, and RBL-2H3 cells. Ethanol extract (90%) of A. lappa (ALE, 100 μg/mL) inhibited the degranulation rate by 52.9%, determined by the level of β-hexosaminidase. ALE suppressed passive cutaneous anaphylaxis (PCA) in rats and attenuated anaphylaxis and histamine release in mice. To identify the active compound of ALE, we subsequently fractionated and determined the level of β-hexosaminidase in all subfractions. Oleamide was identified as an active compound of ALE, which attenuated the secretion of histamine and the production of tumor necrosis factor (TNF)-α and interleukin-4 (IL-4) in cells treated with compound 48/80 or A23187/phorbol myristate acetate (PMA). Oleamide suppressed FcεRI-tyrosine kinase Lyn-mediated pathway, c-Jun N-terminal kinases (JNK/SAPK), and p38 mitogen-activated protein kinases (p38-MAPKs). These results showed that ALE and oleamide attenuated allergic reactions and should serve as a platform to search for compounds with antiallergic activity.

Interference of oleamide with analytical and bioassay results

“…In the last part of this study, oleamide and a plastic syringe extract, which showed to contain oleamide, appeared to interfere with the current (inflammatory) bioassay as they exhibited activity. Several biological studies have already reported anti-inflammatory activity of oleamide [9][10][11][12][13] in concentration of 100 μg mL −1 12 . In our employed bioassay system, oleamide showed small but significant (p < 0.001) anti-inflammatory activity in high doses (100 μg mL −1 ).…”

“…Various other pharmacological effects of oleamide such as cannabinoid like behaviour 6,14 , inhibition of the enzyme human monoamine oxidase B 8,15 , closure of gap-junctions 16 and activation of TRPV1 vanilloid receptors 16 are also communicated. Despite the already reported studies regarding bioassay interferences 8,15,17 from plastic labware leachables, including oleamide, it has been continuously reported as analyte in natural extracts 5,11,12,[18][19][20][21] . At the same time, it has been rarely double checked to be a possible plastic labware interference 22-25 , perhaps due to its natural origin.…”

“…The next aim of the study was to develop a simple UHPLC-ESI-MS method, which will help researchers to identify oleamide-leaching labware. Due to oleamide's proven activity in some cell-based bioassays, including anti-inflammatory effects [9][10][11][12][13] , experiments on TLR4 antagonistic activity aiming to show interferences in the biological response were performed as well.…”

Anti-inflammatory effects of cinnamon extract and identification of active compounds influencing the TLR2 and TLR4 signaling pathways

“…Bioassay-guided fractionation is a well-established approach for untargeted, but focused screening of active compounds in complex matrices. [44][45][46][47][48] From the identified compounds (Table S2 †), p-cymene, cinnamyl alcohol, cinnamic acid and cinnamalde-hyde are present in Cinnamomum verum extract, with the latter as major active principle. 15,24,49,50 To the best of our knowledge, the other compounds shown in Table S2 † were not reported to be present in cinnamon extract so far.…”

Therapeutic Value of Arctium Lappa Linn. – A Review

“…Ethanol extract (90%) of AL (ALE, 100 µg/mL) inhibited the degranulation rate by 52.9%, determined by the level of β-hexosaminidase. ALE suppressed PCA in rats and attenuated anaphylaxis and histamine release in mice [68].…”