Sami Fattouch

Quince (Cydonia oblonga Miller) peel polyphenols modulate LPS-induced inflammation in human THP-1-derived macrophages through NF-κB, p38MAPK and Akt inhibition.

Chronic inflammation is a hallmark of several pathologies, such as rheumatoid arthritis, gastritis, inflammatory bowel disease, atherosclerosis and cancer. A wide range of anti-inflammatory chemicals have been used to treat such diseases while presenting high toxicity and numerous side effects. Here, we report the anti-inflammatory effect of a non-toxic, cost-effective natural agent, polyphenolic extract from the Tunisian quince Cydonia oblonga Miller. Lipopolysaccharide (LPS) treatment of human THP-1-derived macrophages induced the secretion of high levels of the pro-inflammatory cytokine TNF-α and the chemokine IL-8, which was inhibited by quince peel polyphenolic extract in a dose-dependent manner. Concomitantly, quince polyphenols enhanced the level of the anti-inflammatory cytokine IL-10 secreted by LPS-treated macrophages. We further demonstrated that the unexpected increase in IL-6 secretion that occurred when quince polyphenols were associated with LPS treatment was partially responsible for the polyphenols-mediated inhibition of TNF-α secretion. Biochemical analysis showed that quince polyphenols extract inhibited the LPS-mediated activation of three major cellular pro-inflammatory effectors, nuclear factor-kappa B (NF-κB), p38MAPK and Akt. Overall, our data indicate that quince peel polyphenolic extract induces a potent anti-inflammatory effect that may prove useful for the treatment of inflammatory diseases and that a quince-rich regimen may help to prevent and improve the treatment of such diseases.

Use of Optimised PCR Methods for the Detection of GLRaV3: A Closterovirus Associated with Grapevine Leafroll in Tunisian Grapevine Plants

We report a modification and optimisation of a previously published procedure (Minafra and Hadidi, 1994) for the detection of GLRaV3 in infected grapevine plants. GLRaV3 RNA was successfully detected not only in total crude nucleic acid extracts of infected grapevine tissues but also in viruliferous mealybug extracts by IC-RT-PCR. This detection was rapid, sensitive and specific without occurrence of any background. A comparative ELISA, RT-PCR and IC-RT-PCR assays were carried out and revealed the greater sensitivity and specificity of PCR techniques.

RNA oligoprobe capture RT-PCR, a sensitive method for the detection ofGrapevine fanleaf virus in Tunisian grapevines

A simple, sensitive and specific RNA capture method is described for the detection of Grapevine fanleaf virus (GFLV) in infected grapevines. This method consists of hybridizing GFLV-RNAs to oligoprobes immobilized on nylon membranes, followed by RT-PCR amplification of targeted viral sequences. The RNA oligoprobe capture RT-PCR method is 10-fold more sensitive than IC-RT-PCR. The efficiency of the RNA oligoprobe capture RT-PCR and the reuse of immobilized oligoprobe membranes without loss of efficiency could make this procedure suitable for the routine diagnosis of GFLV in grapevines.

Quince peel polyphenolic extract blocks human colon adenocarcinoma LS174 cell growth and potentiates 5-fluorouracil efficacy

BackgroundDevelopment of alternative cancer-specific drugs would be of paramount importance to overcome toxicity toward normal tissues and tumor resistance. Here, we investigated the potential anti-tumoral effect of peel (Peph) and pulp polyphenolic extracts from the Tunisian quince Cydonia oblonga Miller on both no-tumorigenic cells NIH 3T3 Fibroblasts and HEK 293 cells and human colon adenocarcinoma LS174 cells.MethodsCell proliferation and cytotoxicity were measured with MTT and LDH assays respectively. Cell cycle distribution and the apoptosis levels were assessed by flow cytometry. Intracellular reactive oxygen species (ROS) levels were determined using the fluorescent probe CM-H2DCFDA. Western blot was used to further characterize cell death and analyze the signaling pathways affected by Peph treatment. The expression level of VEGF-A was evaluated by real time quantitative PCR and further verified by quantifying the secreted cytokines by enzyme-linked immunosorbent assay.ResultsWe found that Peph extract displayed the highest anti-proliferative effect specifically on LS174 cells. However, each Peph phenolic compound alone did not exhibit any anti-proliferative activity, suggesting a synergistic effect of phenolic molecules. Such effect was associated with a cell cycle arrest in the G1/S phase, a caspase-independent apoptosis and an increase of the ROS production. Peph extract inhibited the pro-survival signaling pathway NFκB and suppressed the expression of various cellular markers known to be involved in cell cycling (cyclin D1) and angiogenesis (Vascular Endothelial Growth Factor, VEGF). Interestingly, the combination Peph extract and 5-FU exerted synergistic inhibitory effect on cell viability.ConclusionThese data propose the quince Peph extract as a promising cost effective non toxic drug to employ alone or in combination with conventional anti-colorectal cancer. Moreover, quince rich regimen may prevent the development and the progress of colon cancer.