Abstract

The increasing prevalence of antibiotic resistant bacteria poses a global health crisis and is worsened by the over prescription of antibiotics as well as the lack of funding for novel antibiotic research. New antibiotic compounds can be found by researching botanicals, specifically those used in traditional medicine which contain a variety of phytoactive compounds, some of which possess antibacterial, antiviral, and or antifungal properties. In the present study three botanicals used in traditional Cherokee medicine were screened for antibacterial activity and the presence of known antibacterial compounds: Hydrastis Canadensis (Goldenseal), Achillea millefolium (Yarrow), and Geranium maculatum (Geranium). These botanicals were selected due to their traditional uses for treating ailments likely caused by bacterial infections. Essential oils were extracted and collected in fractions using supercritical fluid extraction with carbon dioxide as solvent and a 95% ethanol cosolvent modifier. A broth microdilution assay was used to test if the extract fractions inhibited the growth of gram-positive bacteria, Staphylococcus aureus (SA), or gram-negative bacteria, Escherichia coli (EC). After identifying a fraction that inhibits growth; the pressure, temperature, and solvent flow rates for a second extraction are modeled around the active fraction. This process can be repeated to find the parameters yielding the highest concentration of antibacterial activity. These fractions will be tested using the same microbroth dilution assay, and if antibacterial activity is demonstrated again, further research will be conducted to identify the active compound using liquid chromatography-mass spectrometry (LC-MS). Standards of seven known active compounds in goldenseal were purchased and characterized using LC-MS to compare with the mass spectra of the active extracts. These comparisons will help determine if the antibacterial activity is due to a known molecule or a novel one, and if it is a novel compound LC-MS will be used in attempt to characterize it.

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