VALIDATION OF PLANTS TRADITIONALLY USED FOR SKIN INFLAMMATION
Creators: name: KHALILPOUR, SABA
Publisher: name: Universit� degli Studi di Milano
Year: 2019

description: Rhus coriaria L. (R. coriaria), Arctium lappa L. (A. lappa) and Echium amoenum Fisch. (E. amoenum) are medicinal herbs with extensive traditional uses, covering anti-inflammatory skin therapy. The present research aims to investigate the anti-inflammatory effects of different extracts of R. coriaria fruit, A. lappa roots and the E. amoenum flowers in human keratinocytes (HaCaT cells), evaluating extracts prepared using different techniques. Firstly, the herbal extracts were prepared using different methods including cold extraction, maceration, and decoction. The extraction solvents used were water, ethanol, ethanol-water (50:50), acetone, ethyl acetate, and dichloromethane. In the first phase of this study the extracts of E. amoenum, A. lappa and the polar (water (WRC), ethanol-water (EWRC), ethanol (ERC) and macerated ethanol (mERC)) extracts of R. coriaria were tested. The cytotoxicity and IL-8 release using, respectively, MTT and ELISA assays, were performed after 6 hours of TNF-? (10 ng/mL) treatment. Based on these results, the mERC and the EWRC were selected as the active extracts and assessed for NF-?B driven transcription, following identical treatment conditions. A non-toxic extract of A. lappa (EWAL) was also tested for its effect on NF-?B signaling. According to the preliminary data obtained, R. coriaria showed the most consistent and promising effects in inhibition of lL-8 and NF-?B signaling.Therefore, starting from this phase of the research the main focus of the study was on this herb and selectively mERC and the EWRC as the active extracts. The challenged cells by TNF-?, under treatment conditions with mERC and EWRC, were analysed for ICAM-1, VEGF, and MMP-9 releases, as well as NF-?B translocation, by ELISA assays. In addition, both active extracts were investigated for the inflammation induced by UVB (40 mJ/cm2) and were chemically profiled through HPLC-UV-DAD analysis. In the second phase of this research, the lipophilic extracts of R. coriaria (ARC, EARC and DCMRC) were evaluated using the cytotoxicity and IL-8 release assays in TNF-? or PMA-treated cells. Based on these results, active extracts were measured for their effects on NF-?B driven transcription. Among the evaluated herbs, only R. coriaria extracts achieved anti-IL-8 activity. Although all the polar extracts of this plant inhibited the TNF-?-induced IL-8 release, just mERC and EWRC suppressed NF-?B activation, ICAM-1, and MMP-9 secretion. EWRC showed higher inhibition on ICAM-1 and MMP-9 with IC50s of 1.76 � 0.24 and 1.24 � 0.33 �g/mL, respectively (mean � s.d.). On the contrary, mERC significantly decreased VEGF levels whereas EWRC did not show any effect. The HPLC-UV profile of the extracts revealed higher amount of anthocyanins in EWRC in comparison with mERC. mERC, which showed lower amount of anthocyanins than EWRC, blocked both UVB-induced IL-8 release (with IC50 of 7.61 ?g/mL) and translocation of NF-?B (at 10 ?g/mL), measured by ELISA assay. The R. coriaria acetone (ARC) and ethyl acetate (EARC) extracts significantly inhibited the IL-8 release (at 25 ?g/mL), as well as NF-?B driven transcription (at 50 ?g/mL), when induced by TNF-?. The dichloromethane extract of this herb failed to show IL-8- inhibitory activity against TNF-?. ARC (with IC50s of 25.77 ?g/mL ) and mERC (at 50 ?g/mL) showed a significant effect in inhibiting the PMA induced IL-8 release. ARC modulated PMA-induced NF-?B signaling with IC50 of 27.82 ?g/mL. Our results suggest the potential positive effect of R. coriaria fruit extracts, mostly mERC, as preventive agent in the treatment of keratinocyte inflammation through their inhibitory effect on the production of skin pro-inflammatory mediators. Our findings on the promising inhibitory effects of R. coriria on NF-?B signaling seem to confirm the traditional use of this herb as a remedy to treat skin inflammatory conditions. Its use as skin anti-inflammatory agent deserves further investigation.