2011 Annual Report
Objective 2: Develop and evaluate spectral fingerprinting and chromatographic profiling methods to characterize components in lipid soluble, water soluble, and intermediate fractions of food materials. Sub-objective 2.A.: Develop spectral fingerprinting methods for identification of plant materials and individual components using direct analysis (no prior chromatographic separation) and pattern recognition algorithms. Sub-objective 2.B.: Develop chromatographic profiling methods for identification and quantification of individual components in plant materials.
Objective 3: Develop methods to determine variability of biologically active components in food materials through profiles and/or fingerprints.
Objective 2: Spectral fingerprinting methods will be developed based on ultraviolet and visible molecular absorption (UV/Vis), infrared (IR), near-infrared (NIR), and mass spectrometric (MS) detection. The overlapping complex spectra will be interpreted using pattern recognition programs. The patterns will be used to determine the sensitivity of the different detection systems for discriminating between plant materials based on genera, species, variety, growing year, growing site, and processing conditions. These methods will be developed using 3 food materials and 3 botanical supplement materials. Repeat samples will be examined over a period of years to determine the stability of the spectra and the ability to compare spectra of new materials to archived spectra. The phenolic and vitamin content of the plant materials will also be determined using chromatographic profiling using LC-DAD-ESI/MS. This will make it possible to determine which compounds are contributing most to differences arising from the various growing factors.
Objective 3: The spectral fingerprints can be used with nested analysis of variance to determine the relative variance contributed by each growing factor: species, variety, site, year, plant-to-plant variation, and analytical uncertainty. Samples will be obtained from collaborators across the country and representing a variety of foods and botanical supplements. UV/Vis, IR, and NIR spectra will provide variance data for the integrated chemical composition of the plant materials and MS will provide variance data for specific masses and, with the assistance of chromatographic profiling, specific compounds of health interest.
During this fiscal year, FCMDL has worked on a quantification scheme for flavonoids. In the first phase, we have identified an approach for quantifying flavonol and flavone glycosides and hydroxycinnamic acid derivatives using a single standard. This scheme is critical since there are more than 4600 of these compounds and only 100 standards (fewer than 3%).
FCMDL worked with AOAC INTERNATIONAL to develop guidelines for botanical identification methods. This project is particularly critical to supplement and botanical producers who now must establish appropriate quality assurance methods for all ingredients under FDA’s new GMPs (Good Manufacturing Practices) for dietary supplement ingredients. The guidelines and explanatory appendices are based largely on research at FCMDL.
During this fiscal year, FCMDL established initial contact with the University of Maryland Chemistry Department and FDA for the use of FDA's high-field nuclear magnetic resonance (NMR) spectrometer for metabolomic research. The extreme stability and the universal quantification capability of proton NMR make it the ideal tool for characterizing food materials for small molecules and providing reference spectra for different genus and species.
FCMDL developed methods for the extraction of phenolic compounds from wheat and determined the phenolic concentration in each ground wheat fraction. We compared the phenolic acid composition and the antioxidant capacity of five spring wheat cultivars from eastern Washington state: two soft white cultivars (Alpowa and Louise), two hard wheat cultivars (Blanca Grande and Macon), and a hard red cultivar (Westbred 936). To date we have compared three commonly used extraction solvent mixtures for extracting soluble phenolics from the grain samples.
Luthria, D.L., Mukhopadhyay, S., Lin, L., Harnly, J.M. 2011. A statistical evaluation of spectral fingerprinting methods using analysis of variance and principal component analysis. Food Chemistry. 65:80-85.
Singh, A.P., Luthria, D.L., Freeman, M., Olson, R., Bilenker, D., Shah, S., Somasundaram, S., Vorsa, N., Wilson, T. 2011. LC-MS-MS characterization of curry leaf flavonols and antioxidant activity. Food Chemistry. 127:80-85.
Chen, P., Harnly, J.M. 2011. Rapid Mass Spectroscopic Fingerprinting Method and Principal Component Analysis for Differentiation between American Ginseng, Chinese Ginseng, and Notoginseng. Journal of the Association of Official Analytical Chemists. 94:90-99. Sun, J., Chen, P., Lin, L., Harnly, J.M. 2011. A non-targeted approach to chemical discrimination between green tea extract-based dietary supplements and green tea leaves by LC/MS. Journal of the Association of Official Analytical Chemists. 94:487-497.
Lin, L., Jianghao, S., Chen, P., Harnly, J.M. 2011. LC-PDA-EIS/MSn identification of new anthocyanins in purple radish (Raphanus sativus L. variety). Journal of Agricultural food Chemistry . 59:6616-6627.
Sun, J., Long-Ze, L., Chen, P. 2011. A flow-injection mass spectrometry fingerprinting method for authentication and quality assessment of Scutellaria lateriflora-based dietary supplements. Analytical and Bioanalytical Chemistry. 401:1577-1584.
Sun, J., Chen, P. 2011. Differentiation of Panax quinquefolius grown in United States and China using LC/MS-based chromatographic fingerprinting and metabolomic approaches. Analytical Biochemistry. 58(8):4545-4553.
Xie, Z., Zhao, Y., Chen, P., Yu, L. 2010. Chromatographic fingerprint analysis and rutin and quercetin compositions in the leaf and whole-plant samples of di- and tetraploid Gynostemma pentaphyllum. Journal of Agricultural and Food Chemistry. 7:3042-3049.