Date of Award


Degree Name

MS in Biological Sciences


Biological Sciences


College of Science and Mathematics


Alejandra Yep

Advisor Department

Biological Sciences

Advisor College

College of Science and Mathematics


The objectives of this research were to evaluate the antibacterial activity and to determine the chemical composition of a list of medicinal plants used by Native Americans in California. Artemisia californica, Mimulus aurantiacus, Equisetum telmateia, Equisetum hyemale, and Marah fabacea were selected from a list of plants reported as having been used for ailments related to infections by tribes located in California. The extracts obtained through steam distillation from E. telmateia, E. hyemale and M. fabacea were assayed for in vitro antibacterial activity against 16 Gram-negative and 6 Gram-positive bacteria using disk diffusion assays and measuring the diameters of inhibition zones. E. telmateia showed the most promising antibacterial activity. The extracts from A. californica, M. aurantiacus and E. telmateia were analyzed for chemical composition, finding eucalyptol, thujone, eugenol, caryophyllene, germacrene D, and propanal as some of the secondary metabolites identified using GC-MS. Our results suggest that E. telmateia can be a potential source for novel antimicrobials against pathogenic bacteria.