Galegine Content in Goatsrue (Galega officinalis) Varies by Plant Part and Phenological Growth Stage

Abstract

Goatsrue is a member of the Fabaceae family, native to Europe and western Asia. It contains the toxic alkaloid galegine. The objective of the study was to describe galegine concentration in aboveground goatsrue plant parts and total galegine pools over phenological growth stages. Twenty goatsrue plants at four locations were selected and a stalk was harvested from each at five stages of phenological development and separated into parts. Plant parts were freeze-dried, ground, and analyzed with liquid chromatography/mass spectrometry. Galegine concentration was significantly different in plant tissues; reproductive tissues had the highest levels of galegine (7 mg g−1), followed by leaf (4 mg g−1) and finally stem (1 mg g−1) tissues. Galegine concentration and pools varied over plant tissues and phenological growth stages. Galegine pools (dry weight by concentration) or the total amount of galegine per stalk were lowest at the vegetative growth stage (2 mg stalk−1) and increased until reaching a maximum at the immature pod stage (91 mg stalk−1). The pools decreased nearly in half (48 mg stalk−1) by the mature seed stage. Like galegine pools, galegine concentration also reached a maximum at the immature pod stage (4 mg g−1), and decreased by nearly half by the mature seed stage (2 mg g−1). The increased levels of galegine pools at immature pod stage corresponds with the time of meadow hay harvest, implying that goatsrue is potentially most toxic at the phenological stage when it is likely to be harvested as a contaminant in meadow hay.