UBC Theses and Dissertations
Ethnopharmacology of western North American plants with special focus on the genus Artemisia L. McCutcheon, Allison R.
This thesis is comprised of a series of investigations into the pharmacological activities of plants from western North America. In the first phase of the research, one hundred methanolic plant extracts were screened for: antibiotic, antifungal, anti-mycobacterial and antiviral activity. Eighty-nine of these extracts exhibited antibiotic activity and eighty-one exhibited antifungal activity. Nineteen extracts also showed anti-mycobacterial activity. There was a correlation (0.945) between anti-mycobacterial activity and strong activity against the fast growing, non-pathogenic Mycobacterium phlei which was used in the antibiotic screening. Twelve extracts were each active against one of the seven viruses screened. Several interesting observations arose from the analyses of the phase one screening results. There was a significant correlation between anti-mycobacterial activity and the specific usage of the plants to treat tuberculosis. Significantly higher percentages of active plants were found among those categorized as potential antibiotics and antifungals based on their traditional usage. There appeared to be correlations between activity and the taxa to which the active plants belonged and the habitats they were collected from. The phase two screening of one hundred eighty-five extracts was designed to further test these apparent correlations. In these phase two screenings, 77% of the extracts exhibited antibiotic activity. Seventy-five percent (75%) of the plants which were used medicinally were active while only 22% of the non-medicinal plants were active. Of the plants which were classified as potential antibiotics based on their traditional uses, 91% were active. The taxa with the highest percentage of active extracts were the Filicinae and the Gymnospermae. Fifty-nine percent (59%) of the extracts exhibited significant activity in the phase two antifungal screening. The taxon with the largest percentage of active extracts was the Gymnospermae (100% active). There was a great difference in the percentage of active extracts among the traditional plant medicines (32% active) compared to the non-medicinal plants (5% active). Seventy-five percent (75%) of the plants classified as potential antifungals based on their traditional uses were found to have significant activity. Throughout these phase one and two screenings, the members of the genus Artemisia L. assayed were particularity noteworthy for their broad spectrum of activity. Therefore, this genus was chosen for more extensive research on the anti-infectious properties of 74 additional samples from 30 Artemisa taxa. All of the Artemisia samples exhibited antibiotic and antifungal activity. In the antiviral assays, a total of 18 extracts inhibited the virally induced cytopathic effects. A total of twenty-nine extracts exhibited activity in the anti-mycobacterial assays. There were representative samples from each of the four Artemisia subgenera among the active extracts in each of the four screens, although it was noted that the extracts with the strongest activity in the antimycobacterial assays were all members of the subgenera Dracunculus and Tridentatae. In all of the Artemisia assays, there was as much variation in activity among samples of a taxa (species or subspecies) as there was between taxa. Samples of the Artemisia species which were most frequently cited in the ethnobotanical literature (A. dracunculus, A. frigida, A. ludoviciana and A. tridentata) were among the most active extracts in all of the assays.
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