Towards informed cultivation: seasonal variation of rhizoidal alkaloid content in goldenseal(Hydrastis canadesis L.).
Committee: Steve Cartier, Alisa Hove, JJ Apodaca
Herbal products are used in some quantity by 20% of the United States population, and cultivation of medicinal herbs has increased to meet demand. For goldenseal, a valuable and endangered herbal medicinal, it is possible that conventional cultivation methods are yielding crops with reduced medicinal properties compared to wild plants. Conventional methods of growing goldenseal usually involve manipulating growing conditions to reduce stress on crops for maximum biomass yield, but it is possible that growing goldenseal under stress will yield crops with heightened levels of the compounds berberine and hydrastine from which goldenseal derives its medicinal properties. Many medicinal compounds, such as berberine and hydrastine, are secondary metabolites, which are often biosynthesized by plants for self-defense against pathogens, herbivores, and/or environmental stress. In the absence of those stressors, plants may produce lower quantities of the compounds, and thus have reduced medicinal properties. However, the stressors which induce production of berberine and hydrastine in goldenseal are unknown. Studies are needed to indicate which stressors are most probable before future studies can be done to determine optimal cultivation methods for goldenseal. This study aimed to determine whether berberine and hydrastine concentration in goldenseal rhizomes exhibited seasonal and/or site variation. Rhizomes from three established populations were harvested twice, in early June and early September 2015, and concentrations were quantified using reverse- phase HPLC/UV-VIS analysis. Due to mechanical error, berberine was unquantifiable. For hydrastine, there was a significant difference in concentration between sites (p<.0001*), and a significant difference between seasons at one site (p<.0451*). Considering the sites in this study, these results indicate that the stressors of ultraviolet radiation, drought, and poor soil conditions are more likely to be the ones which induce hydrastine production in goldenseal, and thus more compelling to investigate in future studies.