Liquid chromatography-mass spectrometry/mass spectrometry method development for quantification of bioactive compounds in elderberry and garlic botanicals

Dissertation supervisor: Dr. C. Michael Greenlief.Includes vita.Elderberry (Sambucus nigra spp.) juice contains a variety of polyphenols mostly anthocyanins. In order to understand the variation of polyphenol levels by genotype, various elderberry juice samples were analyzed for total phenolics (TP), total monomeric anthocyanins (TMA) and individual anthocyanin content (IAC). The Folin-Ciocalteu total phenolic method and pH differential method were used to measure the TP and TMA content, respectively. In addition, ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry was used to separate and detect individual anthocyanins from samples prepared by solid phase extraction. Multiple-reaction-monitoring was used to process data for the reduction of false positives, maximizing selectivity, and reliable quantification. The quantitative performance of the method was validated, and a detection limit of 0.3 ng/mL for cyanidin 3-O-glucoside was determined. This newly developed method may serve to characterize and profile various anthocyanins in elderberry juices for quality control, assessment of dietary intake, and anthocyanin-based biomedical studies. The effects of frozen storage on the anthocyanin and polyphenol content of elderberry fruit juice are investigated. Juice from three genotypes of American elderberry (Adams II, Bob Gordon, and Wyldewood) was screened for total phenolic and total monomeric anthocyanin content with spectrophotometric methods. The individual anthocyanin content of the juice was tested by coupling solid phase extraction with ultraperformance liquid chromatography/tandem mass spectrometry. Juice samples were tested initially upon harvest, then again after 3, 6, and 9 months of frozen storage. The three different genotypes of juice had significantly different TP, TMA, and IAC profiles initially (p<0.05). The TP, TMA, and IAC content of different genotypes were significantly affected (p