Influence of Processing on the Content of Toxic Carboxyatractyloside and Atractyloside and the Microbiological Status of Xanthium sibiricum Fruits (Cang'erzi).

The dried ripe fruits of Xanthium sibiricum (Cang'erzi) are used in traditional Chinese medicine for the treatment of nasal congestion, nasal discharge, allergic rhinitis, sinusitis, and wind-cold headaches. Carboxyatractyloside and atractyloside are important constituents of the fruits because these diterpenoid glycosides are responsible for their toxicity. In order to evaluate procedures for reducing the amount of the more toxic carboxyatractyloside, the fruits were dried and heated with different methods. Carboxyatractyloside and atractyloside were analysed by a new reversed-phase high-performance liquid chromatographic method using liquid chromatography-diode array detector-tandem mass spectrometry analysis. The results revealed that temperature and drying methods have a strong influence on the content of carboxyatractyloside and atractyloside. Fruits which were treated at higher temperatures showed a lower content of carboxyatractyloside and an increased content of atractyloside, which is 50 times less toxic. This indicates that the roasting process can reduce toxicity effectively. The microbiological colonisation of Xanthium fruits is also reduced by roasting and by drying above 100 °C. For the safe use of Cang'erzi, the effect of processing should be monitored and analysis of carboxyatractyloside and atractyloside should be obligatory in quality control.

In vitro detection of contact allergens: development of an optimized protocol using human peripheral blood monocyte-derived dendritic cells.

Allergic contact dermatitis is a delayed T-cell mediated allergic response associated with relevant social and economic impacts. Animal experiments (e.g. the local lymph node assay) are still supplying most of the data used to assess the sensitization potential of new chemicals. However, the 7th amendment to the EU Cosmetic Directive will introduce a testing ban for cosmetic ingredients after 2013. In vitro alternative methods are thus being actively developed. Although promising results have been obtained with cell lines, their reduced functionality and inherent genomic instability led us to reinvestigate the use of peripheral blood monocyte-derived dendritic cells (PBMDCs) for the establishment of a reliable in vitro sensitization test. To solve the issues associated with the use of primary cells, the culture and exposure conditions (cytokine concentrations, incubation time, readout, pooled vs. single donors and cytotoxicity) were re-assessed and optimized. Here we propose a stable and reproducible protocol based on PBMDCs. This should allow a wider acceptance of PBMDCs as a reliable test system for the detection of human skin sensitizers and the inclusion of this protocol in an integrated testing strategy.

A novel in vitro method for the detection and characterization of photosensitizers.

Photoactivation and binding of photoactive chemicals to proteins is a known prerequisite for the formation of immunogenic photoantigens and the induction of photoallergy. The intensive use of products and the availability of new chemicals, along with an increasing exposure to sun light contribute to the risk of photosensitizing adverse reactions. Dendritic cells (DC) play a pivotal role in the induction of allergic contact dermatitis. Human peripheral blood monocyte derived dendritic cells (PBMDC) were thus perceived as an obvious choice for the development of a novel in vitro photosensitization assay using the modulation of cell surface protein expression in response to photosensitizing agents. In this new protocol, known chemicals with photosensitizing, allergenic or non-allergenic potential were pre-incubated with PBMDCs prior to UVA irradiation (1 J/cm(2)). Following a 48 h incubation, the expression of the cell surface molecules CD86, HLA-DR and CD83 was measured by flow cytometry. All tested photosensitizers induced a significant and dose-dependent increase of CD86 expression after irradiation compared to non-irradiated controls. Moreover, the phototoxicity of the chemicals could also be determined. In contrast, (i) CD86 expression was not affected by the chosen irradiation conditions, (ii) increased CD86 expression induced by allergens was independent of irradiation and (iii) no PBMDC activation was observed with the non-allergenic control. The assay proposed here for the evaluation of the photoallergenic potential of chemicals includes the assessment of their allergenic, phototoxic and toxic potential in a single and robust test system and is filling a gap in the in vitro photoallergenicity test battery.