Characterization of Major Flavonols in Ramps (Allium tricoccum)

Ramps (Allium tricoccum) is a traditional plant in the eastern Appalachian Mountains. Ramps have been used in Appalachian folk medicine for its health promoting roles in lowering blood pressure and cholesterol. Information on the chemical composition of bioactive components responsible for the potential health benefits are scarce. Analysis of the chemical composition in similar Alliumplants showed that flavonols, induced similar health benefits. Therefore, the aim of this work is to characterize major flavonol conjugates in ramps. The secondary aim is to develop a preliminary quantification protocol. Flavonol glycosides were extracted in 50% methanol and 3% acetic acid. Characterization of flavonol glycosides was conducted using UHPLC-PDA-MS2. For acid hydrolysis protocol, flavonol glycosides extracts or plant tissues were hydrolyzed by different concentrations of HCl. UHPLC-PDA was used to detect hydrolyzed flavonols. Characterization showed that the major putative flavonol glycosides were kaempferol sophoroside glucuronide, quercetin sophoroside glucuronide, and quercetin dihexoside. The different parts of the putative structures were preliminarily confirmed using 1H and C13NMR analysis. The identified flavonol glycosides were concentrated in leaves. Preliminary quantification protocol showed that optimal hydrolysis conditions of flavonol conjugates was achieved by hydrolyzing the glycosides extract under 3M and 4M HCl, respectively, at 90OC for two hours. To our knowledge, this work is the first to identify major flavonol glycosides content in ramps and develop a preliminary quantification protocol. This finding might explain the past usage of ramps as a medicinal plant