Abstract
The leaves of California mugwort (Artemisia douglasiana) have been used by Native California tribes to treat colds, gastrointestinal problems, infections, dysmenorrhea, and premenstrual syndrome. Previous work in this lab has shown that ethanolic and hexane extracts of dried A. douglasiana leaves are cytotoxic towards estrogen receptor positive (ER+) and ER- breast cancer cells; and a cytotoxic compound was isolated but not characterized. The goal of this study is three-fold: to determine the effect of ethanolic and aqueous extracts on normal cells, to check the reproducibility of the previously developed isolation scheme using a new sample of leaves, and to evaluate and improve upon the previously developed isolation scheme. Results showed that both ethanolic and aqueous extracts are more cytotoxic towards normal human peripheral blood mononuclear cells than towards MDA-MB-231 breast cancer cells. Therefore, even when the cytotoxic constituents are isolated, they cannot be used as a cure for breast cancer. To assess reproducibility, separation techniques that were used in the previous study were repeated with a new sample of A. douglasiana leaves. Chromatograms of previous study extracts are different than current study’s extract, and the cytotoxic compound isolated in the previous study was not present in the new extract. This indicates that this cytotoxic compound is degraded in the previous extract and that the chemical composition of mugwort leaves changes seasonally. The results of vacuum distillation showed that the cytotoxic constituents are not volatile, so the detection method was switched from gas chromatography/mass spectrometry to high performance liquid chromatography/charged aerosol detection (HPLC-CAD). A solid-liquid extraction step was added to the isolation scheme. The reproducibility of fractionation by flash column chromatography was improved. In the future, the cytotoxic constituents can be isolated from the extract from the current study.