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Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

First Advisor

R. Neil Reese


Ten South Dakota native plants were extracted with ethanol and screened against 12 bacterial strains (gram positive and negative) using the disk susceptibility test. Positive control for these screenings was the commercial antibiotic gentamicin. Cytotoxicity of the plant extracts was determined through the use of the brine shrimp lethality test, in which Artemia salina (brine shrimp) are exposed to varying concentrations of the plant extracts for 24 hours. Of these 10 plants, four demonstrated the greatest bacterial inhibition: Arctostaphylos uva-ursi, Monarda fistulosa, Sanguinaria canadensis and Physalis virginiana. P. virginiana was active against eight species of bacteria, inhibiting primarily gram positive bacterial species. Furthermore, P. virginiana had a low cytotoxicity which indicated that the plant would be valuable for further study. Crude P. virginiana extract was separated using a flash chromatography column (1000 ml), which was washed with 1500 ml each of 10%, 20%, 30%, 40% and 100% methanol in dichloromethane. Purification was achieved through preparative HPLC with methanol and water as the mobile phase. Three active peaks were collected and further analyzed using Mass Spectrometry and NMR which preliminarily identified [sic] the active compounds as withanolides.

Library of Congress Subject Headings

Physalis -- Therapeutic use
Anti-infective agents
Natural products
Medicinal plants
Endemic plants -- South Dakota




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