CARATTERIZZAZIONE FITOCHIMICA E VALUTAZIONE DELL'ATTIVITA' BIOLOGICA DI INGREDIENTI BOTANICI CONTENUTI IN INTEGRATORI ALIMENTARI

Backround Botanicals and in particular plant food supplements (PFS) receive great acceptance by European consumers. Potentially, they can deliver significant health benefits at relatively low costs. However, quality and efficacy of these products remain a question of concern, and bottlenecks in risk and benefit assessments need to be solved. PlantLIBRA (PLANT food supplements: Levels of Intake, Benefit and Risk Assessment) is an European Community funded project aiming to foster the safe use of food supplements containing botanicals or their preparations, by evaluating the quality and health benefits of PFS, and by increasing science-based decision-making by regulators and food chain operators. Part of the project is dedicated to the methodology of benefit assessment for PFS, application and validation. The first step was to review the evidence for PFS benefit from epidemiological, clinical and intervention studies. A number of pathological conditions where PFS are commonly used were identified and inflammation was one of those. Considering the difficulties and the high costs in performing human studies, it is clear the necessity to develop in vitro models able to represent the in vivo conditions. We developed a gastric inflammation in vitro model which investigate whether infusions of green and black tea inhibit the NF-kB driven transcription in human epithelial gastric AGS cells. Materials and methods The literature review considered Olea europea L., Camellia sinensis L., Vitis vinifera L., Matricaria recutita L., Urtica dioica, L. Symphytum officinalis L., Calendula officinalis L., Curcuma longa L., Boswellia serrata Roxb., and Harpagophytum procumbens L. which are herbal material frequently used also as food. Electronic literature searches were conducted using the following databases: Cochrane library, Scifinder Scholar, Embase and Pubmed from 1970 to 2010. In the experimental work infusions were prepared with green and black tea of different brands, with or without caffeine, available on the Italian market. For comparison, a freeze-dried water extract of green tea dry water extract industrially prepared was also tested. Firstly, the phenolic content of green and black tea water extracts was determined by using Folin-Ciocalteu’s assay and the catechin content by HPLC-UV. Then, the anti-inflammatory activity in human epithelial gastric cells was evaluated by NF-kB assay. The antioxidant activity of the extracts was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay. The decay of phenols and catechin content at the expiry date was also evaluated in two samples. Results The search retrieved 1830 publications. By applying the inclusion/exclusion criteria, the final number of papers was 138. Some plants showed promising results but it is advisable to conduct further studies with more homogeneous population and larger number of subjects by avoiding the heterogeneity of the herbal preparations considered. Surprisingly, it was impossible to draw conclusions for the anti-inflammatory effect of Camellia sinensis L. both as green and black tea. Considering these results and taking into account the difficulties and the high costs in performing human studies, it is clear the necessity to develop in vitro models able to represent the in vivo conditions. We developed a gastric inflammation in vitro model which investigate whether infusions of green and black tea inhibit the NF-kB driven transcription in human epithelial gastric AGS cells. Infusions were prepared with green and black tea of different brands, with or without caffeine, available on the Italian market. For comparison, a freeze-dried water extract of green tea dry water extract industrially prepared was also tested. Catechin and caffeine content were evaluated by HPLC analysis. The decay of phenols and catechin content three months after the expiry date was also evaluated in two samples. Inhibition of NF-B driven transcription and free radical scavenger activity were observed and the effect correlated with catechin levels. In one decaffeinated sample of green tea, the phenol and catechin content was very low, probably a consequence of caffeine removal. At the expiry date, the loss of catechin levels did not cause any reduction of the inhibition of NF-kB driven transcription. Conclusions For the plants considered relevant in inflammation area, it is advisable to conduct further studies with more homogeneous population and larger number of subjects by avoiding the heterogeneity of the herbal preparations considered. The in vitro model developed in this study could be useful to represent the in vivo physiological conditions. The results will be implemented with studies on biological activity of active compounds after gastro-intestinal metabolism.