SEPARATIONS/STRUCTURE/BIOAVAILABILITY/KRAUS, GEORGE

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The Separations/Structure/Bioavailability core will provide a resource for the extraction, fractionation and structural determination of phytochemicals. The core will build upon the experience gained by the Kraus group in the preparation of standards and structural identification of phytochemicals plus the experience gained by the Murphy group in the extraction and fractionation of Echinacea and Hypericum samples. Extraction, fractionation and structural determination/standard preparation will be conducted in close partnership with individual projects within the Center. Bioavailability studies will be conducted on bioactive compounds to determine if these chemicals are absorbed and reach relevant cellular targets. Our objectives are to: 1. Provide project researchers with extracts of medicinal plants including Hypericum, Echinacea and Prunella vulgaris. Ultrasonication and Soxhlet extraction methods will be compared to determine which method provides the most useful extracts. 2. Fractionate bioactive extracts to determine if activities separate into specific or multiple fractions. Collection of compounds of interest across gradients on HPLC will be a primary fractionation strategy. 3. Determine the structures of individual components of medicinal plants. A combination of spectroscopic methods (IR, NMR, mass spectroscopy) 4. Provide standards for chemical fingerprinting and testing. The preparation of herbal compound standards that are not commercially available will be based upon novel methods for synthesizing Echinacea alkamide- related ketones and a patented method for procyanidin synthesis developed by the Kraus laboratory. Other synthetic approaches will be developed as needed for compounds of important bioactivity. 5. Determine the bioavailability of extracts, fractions and components. CaCo-2 cells will be used as a model for human intestinal uptake and metabolism of herbal compounds of interest, as well as interactions between fractions that may alter compound uptake. Glucuronide conjugates are expected to be major and less bioactive metabolites from herbal phenolics; the inducibility of glucuronide metabolism by herbal components will also be studied.