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Research Paper | Medicinal Plants | United States of America | Volume 12 Issue 9, September 2023

Antimicrobial Effects of Native California Plants: Grindelia Stricta Platyphylla and Iris Douglasiana

Sasha Nealand | Christine L. Case

Abstract: The secondary metabolites of traditional medicinal plants are a potential source of new antibiotics (6). Two local plants with a tradition of use by California native tribes are Grindelia stricta platyphylla (coastal gum weed), a remedy used internally for respiratory and skin ailments and Iris douglasiana (Douglas Iris), also used to treat skin sores. Aqueous, ethanolic, acetonic, and ethyl acetate plant extracts were tested for antimicrobial activity, using the disk diffusion method, against gram - positive and gram - negative bacteria to determine the most effective extraction solvent. The ethyl - acetate extracts of both plants (Grindelia and Iris) showed the most antimicrobial activity, inhibiting growth of gram - positive Mycobacterium phlei and Staphylococcus aureus. For Grindelia aerial parts: the MIC was 0.0898 ?g/?l against M. phlei and 0.346 ?g/?l against S. aureus, the MBC was 0.1796 ?g/?l against M. phlei but did not kill S. aureus. For Iris rhizomes: the MIC was 0.1944 ?g/?l against M. phlei and 0.0970 ?g/?l against S. aureus, the MBC was 0.1944 ?g/?l against S. aureus but did not kill M. phlei. Preliminary phytochemical screening was also done on the extracts. Our hypothesis is that the California Native plants, Grindelia stricta platyphylla and Iris douglasiana, will have antimicrobial activity.

Keywords: medicinal plant constituents, plant extract, ethyl acetate, California native plants, Grindelia stricta platyphylla, Iris douglasiana, antibiotic testing, antimicrobial activity, anti - mycobacteria, phytochemical screening

Edition: Volume 12 Issue 9, September 2023,

Pages: 673 - 675