ß-Sitosterol Reduces the Expression of Chemotactic Cytokine Genes in Cystic Fibrosis Bronchial Epithelial Cells.

Extracts from Nigella arvensis L. seeds, which are widely used as anti-inflammatory remedies in traditional medicine of Northern Africa, were able to inhibit the expression of the pro-inflammatory neutrophil chemokine Interleukin (IL)-8 in Cystic Fibrosis (CF) bronchial epithelial IB3-1 cells exposed to the Gram-negative bacterium Pseudomonas aeruginosa. The chemical composition of the extracts led to the identification of three major components, ß-sitosterol, stigmasterol, and campesterol, which are the most abundant phytosterols, cholesterol-like molecules, usually found in plants. ß-sitosterol (BSS) was the only compound that significantly reproduced the inhibition of the P. aeruginosa-dependent expression of IL-8 at nanomolar concentrations. BSS was tested in CF airway epithelial CuFi-1 cells infected with P. aeruginosa. BSS (100 nM), showed a significant and consistent inhibitory activity on expression of the P. aeruginosa-stimulated expression chemokines IL-8, GRO-α GRO-ß, which play a pivotal role in the recruitment of neutrophils in CF inflamed lungs. Preliminary mechanistic analysis showed that BSS partially inhibits the P. aeruginosa-dependent activation of Protein Kinase C isoform alpha, which is known to be involved in the transmembrane signaling activating IL-8 gene expression in bronchial epithelial cells. These data indicate BSS as a promising molecule to control excessive lung inflammation in CF patients.

Modulation of expression of IL-8 gene in bronchial epithelial cells by 5-methoxypsoralen.

Persistent recruitment of neutrophils in the bronchi of cystic fibrosis patients contributes to airway tissue damage, suggesting the importance of intervening on the expression of the neutrophil chemokine IL-8. Extracts from plants have been investigated to select components able to reduce IL-8 expression in bronchial epithelial cells challenged with Pseudomonas aeruginosa. Extracts and purified components have been added to cells 24 h before pro-inflammatory challenge with P. aeruginosa and IL-8 transcription was quantified in the IB3-1 CF cells in vitro. P. aeruginosa-dependent IL-8 mRNA induction was increased by Argemone mexicana and Vernonia anthelmintica whereas no significant modification of transcription was observed with Aphanamixis polystachya, Lagerstroemia speciosa and Hemidesmus indicus. Finally, inhibition of IL-8 was observed with Polyalthia longifolia (IC50=200 microg/ml) and Aegle marmelos (IC50=20 microg/ml). Compounds from A. marmelos were isolated and identified by GC-MS. No significant effect was observed with butyl-p-tolyl sulphate, whereas the inhibition obtained with 6-methyl-4-chromanone concentration was accompanied by an anti-proliferative effect. On the contrary, 5-methoxypsoralen resulted in IL-8 inhibition at 10 microM concentration, without effects on cell proliferation. In synthesis, 5-methoxypsoralen can be taken into consideration to investigate mechanisms of neutrophil chemotactic signalling and for its potential application in modulating the excessive CF lung inflammation.

Docking of molecules identified in bioactive medicinal plants extracts into the p50 NF-kappaB transcription factor: correlation with inhibition of NF-kappaB/DNA interactions and inhibitory effects on IL-8 gene expression.

BACKGROUND: The transcription factor NF-kappaB is a very interesting target molecule for the design on anti-tumor, anti-inflammatory and pro-apoptotic drugs. However, the application of the widely-used molecular docking computational method for the virtual screening of chemical libraries on NF-kappaB is not yet reported in literature. Docking studies on a dataset of 27 molecules from extracts of two different medicinal plants to NF-kappaB-p50 were performed with the purpose of developing a docking protocol fit for the target under study. RESULTS: We enhanced the simple docking procedure by means of a sort of combined target- and ligand-based drug design approach. Advantages of this combination strategy, based on a similarity parameter for the identification of weak binding chemical entities, are illustrated in this work with the discovery of a new lead compound for NF-kappaB. Further biochemical analyses based on EMSA were performed and biological effects were tested on the compound exhibiting the best docking score. All experimental analysis were in fairly good agreement with molecular modeling findings. CONCLUSION: The results obtained sustain the concept that the docking performance is predictive of a biochemical activity. In this respect, this paper represents the first example of successfully individuation through molecular docking simulations of a promising lead compound for the inhibition of NF-kappaB-p50 biological activity and modulation of the expression of the NF-kB regulated IL8 gene.

Pyrogallol, an active compound from the medicinal plant Emblica officinalis, regulates expression of pro-inflammatory genes in bronchial epithelial cells.

The most relevant cause of morbidity and mortality in cystic fibrosis (CF) patients is the lung pathology characterized by chronic infection and inflammation sustained mainly by Pseudomonas aeruginosa (P. aeruginosa). Innovative pharmacological approaches to control the excessive inflammatory process in the lung of CF patients are thought to be beneficial to reduce the extensive airway tissue damage. Medicinal plants from the so-called traditional Asian medicine are attracting a growing interest because of their potential efficacy and safety. Due to the presence of different active compounds in each plant extract, understanding the effect of each component is important to pursue selective and reproducible applications. Extracts from Emblica officinalis (EO) were tested in IB3-1 CF bronchial epithelial cells exposed to the P. aeruginosa laboratory strain PAO1. EO strongly inhibited the PAO1-dependent expression of the neutrophil chemokines IL-8, GRO-alpha, GRO-gamma, of the adhesion molecule ICAM-1 and of the pro-inflammatory cytokine IL-6. Pyrogallol, one of the compounds extracted from EO, inhibited the P. aeruginosa-dependent expression of these pro-inflammatory genes similarly to the whole EO extract, whereas a second compound purified from EO, namely 5-hydroxy-isoquinoline, had no effect. These results identify Pyrogallol as an active compound responsible for the anti-inflammatory effect of EO and suggest to extend the investigation in pre-clinical studies in airway animal models in vivo, to test the efficacy and safety of this molecule in CF chronic lung inflammatory disease.