Browsing by Author "Supina, Brittany"
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Item Antimicrobial screening of phytochemicals produced by Albertan invasive weeds(2021) Supina, Brittany; Bott, Tina; Harcombe, KimberleyAntibiotic resistance has rendered many clinically-used antibiotics ineffective, creating an urgent need for new antimicrobial agents. Phytochemicals (secondary metabolites produced by plants) are produced in response to environmental stressors, and can inhibit the growth of bacteria, fungi and surrounding plants. Therefore, these phytochemicals offer an alternative source of antimicrobial compounds. The diversity and abundance of phytochemicals produced by plants can increase during the invasion of new habitats, making invasive weeds strong candidates for antimicrobial discovery. Despite this increase in phytochemical production, invasive plant species are often overlooked in favour of medicinal and edible plants, and few studies have characterized their antimicrobial activity. In this research, we used successive Soxhlet extractions with hexane, ethyl acetate, and methanol to extract the phytochemicals from Albertan invasive weed species collected from the Edmonton area. Using Kirby-Bauer disk diffusion assays, extracts were assessed for their ability to inhibit the growth of tester bacterial species including Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus, which represent a range of common pathogens and bacterial types. Preliminary characterizations of extracts from multiple plant species, including common tansy (Tanacetum vulgare) and woolly burdock (Arctium tomentosum), showed promising inhibitory activity against several bacterial species, warranting further investigation. This study provides a starting point for further bioactivity and chemical characterizations of Albertan invasive weeds and highlights these invasive plant species as potential leads for the development of new antimicrobial treatments.Item Method optimization for the antimicrobial screening of pigmented invasive weed extracts(2020) Supina, Brittany; Giebelhaus, J. Duncan; Bott, Tina; Harcombe, KimberleyNew antimicrobial sources are required to address the growing prevalence of antibiotic-resistant pathogens. Secondary metabolites produced by plants (phytochemicals) are widely studied for their bacteria-inhibiting activity. Although the antimicrobial activity of medicinal and edible plants is well-known, few studies have examined compounds derived from invasive weeds. Invasive weeds produce large amounts of phytochemicals and can affect the bacterial composition of soils, making them a potential source of new bacteria-inhibiting compounds. Previously, the antimicrobial activity of Albertan invasive weeds was analyzed using Kirby-Bauer disk diffusion, broth microdilution, and drop check assays. Although the results showed promising bioactivity, plant pigment molecule interference at 600 nm prevented the accurate quantification of this antimicrobial activity during spectrophotometric analysis of broth microdilution assays. These issues highlighted a need for improved antimicrobial screening methods in the presence of pigmented plant extracts. Using ultraviolet-visible spectrophotometry, this study identified 750 nm as a wavelength that is minimally absorbed by phytochemicals in Albertan invasive weed extracts. As verified by bacterial growth curve analysis, this wavelength detects bacterial growth and may be used in broth microdilution assays to quantify antimicrobial activity. These findings offer a method for resolving pigment interference, improving the accuracy of antimicrobial screening of Albertan invasive weed extracts. These findings may also be applicable to the antimicrobial screening of other pigmented plant extracts and compounds. Overall, this method optimization may assist in the identification of new antimicrobial compounds derived from pigmented plant sources.