Determination of bioactive, free isothiocyanates from a glucosinolate-containing phytotherapeutic agent: a pilot study with in vitro models and human intervention.

Isothiocyanates (ITCs) derived from plants of the order Brassicales are known for their antibacterial, anti-inflammatory or anticarcinogenic potential. Although only the free ITCs exert bioactivity, quantification in vivo is almost exclusively performed on total ITC/metabolite content. We therefore investigated in a pilot study the amount of free ITC at different steps critical for therapeutic efficacy. A sensitive and specific GC-MS/MS method for the simultaneous quantification of individual free ITC after solid-phase extraction (SPE) was developed. We show here that release of biologically active ITC from plants occurs at not only alkaline but also acidic pH. Furthermore, in human urine conversion of the ultimate, inactive mercapturic acid conjugate back into its corresponding bioactive form is increased at alkaline as compared to neutral pH. This was also observed in the urine of human volunteers, where - in correlation with the pH value - a mean of 0.16 to 1.03 µmol ITC was detected after oral application of a phytotherapeutic agent containing 30.4 µmol of the initial pro-drugs. The amounts of free ITC being necessary for bioactivity in vitro were found to be indeed achieved in vivo. These data might be helpful to better understand the beneficial effects of ITC observed in vivo.

Indoor aerosol determination with respect to a soiling phenomenon in private residences.

Indoor aerosol exposure has become of major interest since health hazards arising from fine and ultrafine dust particles have become more evident. The study presented here is dedicated to fine and ultrafine dust characterization and determination in more than 150 private residences with special respect to a phenomenon of enhanced soiling. In the scientific community committed to ecological housing and building it is referred to as "black magic dust" though the staining is often film-like in nature. This phenomenon has been observed for 20 years in residences in Europe and North America and there is strong evidence that it is correlated to emission of semivolatile organic compounds (SVOCs) from refurbishing materials. In this study we show that fine dust particle concentrations are elevated in such homes and that there is characteristic particle morphology for "black magic dust" staining. From the results we suggest that elevated particle concentration and particle size are significant to induce a condensation process which causes the observed blackening. Reduced air exchanges due to new insulation standards may also contribute to its occurrence.