Method development for the quantification of bioactive compounds and heavy metals in American elderberry
Authors:   , Perera Nihari D 
Published: September 2024

There are a variety of beneficial compounds found in plant such as polyphenols, carbohydrates, and organic acids. Polyphenols are beneficial compounds that are promoted as antioxidants in dietary supplements. Polyphenols include a diverse group of compounds consisting of flavonoids (which includes a carbohydrate group), phenolic acids, phenolic alcohols, stilbenes, and lignans, for example. Carbohydrates are the primary source of energy for all living organisms. Organic acids are compounds that are abundantly present in ripe fruits which are responsible for their sourness and their flavor. Here we focus on the presence of polyphenols, carbohydrates, and organic acids in eight genotypes (Ozark, Ozone, Bob Gordon, Wyldewood, Adams, Pocahontas, Rogersville, and Kelly) of American elderberry (Sambucus nigra (subsp. canadensis)) pomace from two harvest years (2017 and 2018). Pomace is the waste left over from processing elderberries and we are interested in determining if there is potential commercial value in something that is usually discarded. Here, we describe pomace extraction methods and the development of liquid chromatography parameters, to identify mainly the polyphenols present and their concentrations. We have described several extraction methods used to examine the presence of polyphenolic compounds. The extraction methods use organic solvents followed by solid-phase extraction for sample cleanup prior to analysis. The extracts are then analyzed by reverse phase high performance liquid chromatography-mass spectrometry (HPLC/MS). Further characterization by tandem mass spectrometry (MS/MS) is also performed. Information about the identified phenolic compounds is provided with the use of Riken and Metlin databases. The similarities and differences between the identified polyphenolic compounds among genotypes are discussed. The similarities and differences are statistically analyzed with the use of principal component analysis (PCA) plots, volcano plots, and heat maps with Metaboanalyst 5.0 software. Total phenolic content (TP) was analyzed by the Folin-Ciocalteau method. Here, we describe pomace extraction methods, standard preparation with gallic acid, and Folin-Ciocalteau complex preparation. The complexes are analyzed by ultraviolet-visible (UV-Vis) spectrophotometry. Total monomeric anthocyanin content (TMA) was analyzed by a UV-Vis pH differential method. Here, we describe pomace extraction methods and standard preparation with cyanidine-3-O-glucoside chloride. Metals can contaminate urban and agricultural soil in a variety of ways, including mining, manufacturing, and with synthetic products. Plants play an important role by absorbing and accumulating toxic compounds in their tissues. In this study, we focus on the accumulation of metals in two genotypes (Ozark and Ozone) of American elderberry (Sambucus nigra (subsp. canadensis)) pomace. The goal of this study is to look for metals in elderberry pomace and to determine the concentrations of metals in the elderberry pomace. The concentration of heavy metals in elderberry pomace varies substantially. In this study, we describe microwave digestion methods of the elderberry pomace. The digested samples are then analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). This analysis is completed alongside a multi-element standard series. The accumulation of Mn, Cu, Al, Pb, Zn, Co, Ni, Sr, Cr, Cd and Fe is considered for the analysis. The concentrations of each metal in Ozark and Ozone genotypes are discussed.