Tamarix gallica phenolics protect IEC-6 cells against H 2 O 2 induced stress by restricting oxidative injuries and MAPKs signaling pathways.

Polyphenolic compounds gained interest in the pharmaceutical research area due to their beneficial properties. Herein, antioxidant and cytoprotective capacities of T. gallica extract on H2 O2 -challenged rat small intestine epithelial cells were investigated. To set stress conditions, IEC-6 cultures were challenged with numerous H2 O2 doses and durations. Then, 40μM H2 O2 during 4h were selected to assess the cytoprotective effect of different T. gallica extract concentrations. Oxidative parameters, measured through CAT and SOD activities as well as MDA quantification were assessed. In addition, the expression of possibly involved MAPKs was also valued. Main results reported that T. gallica was rich in polyphenols and exhibited an important antioxidant activity (DPPH Assay, IC50 =6μgmL-1 ; ABTS+ test, IC50 =50μgmL-1 ; Fe-reducing power, EC50 =100μgmL-1 ). The exposure of IEC-6 cultures to 40μM H2 O2 during 4h caused oxidative stress manifested by (i) over 70% cell mortality, (ii) over-activity of CAT (246%), (iii) excess in MDA content (18.4nmolmg-1 ) and (iiii) a trigger of JNK phosphorylation. Pretreatment with T. gallica extract, especially when used at 0.25μgmL-1 , restored cell viability to 122%, and normal cell morphology in H2 O2 -chalenged cells. In addition, this extract normalized CAT activity and MDA content (100% and 14.7nmolmg-1 , respectively) to their basal levels as compared to control cells. Furthermore, stopping cell death seems to be due to dephosphorylated JNK MAPK exerted by T. gallica bioactive compounds. In all, T. gallica components provided a cross-talk between regulatory pathways leading to an efficient cytoprotection against harmful oxidative stimulus.