Student Research Projects

Antimicrobial Activity of Ulva lactuca seaweed extracts

Student Tatyana Zvonareva, '16
Faculty Mentor(s)
Department Chemistry
Course Chemistry 489: Research in the Natural Sciences


It is commonly known that fast rates of pathogenic mutation allow for a rapid development of multidrug resistant pathogens. This results in constant need for new anti-bacterial and anti-viral drugs. As a consequence of increasing demand for therapeutics from natural products, marine organisms became a focus of research in medicinal chemistry. Seaweeds, for instance, provide a variety of structurally diverse secondary metabolites with a high therapeutic potential. Specifically, marine alga Ulva lactuca commonly known as sea lettuce, is an edible green algae distributed throughout the world that have been shown to exhibit antiviral, as well as, antibacterial activity. Therefore, the goal of this study was to assess antimicrobial activity of this alga, as well as, to identify the substances responsible for the antimicrobial activity of this species of seaweed. Two types of extraction techniques were used in the study. In the first extraction method used, the specimen was macerated and extracted concurrently with methanol and toluene, polar and nonpolar solvents, respectively. In a second method, the specimen was macerated in the presence of saline and extracted sequentially with dichloromethane, butanol and ethyl acetate, thereby progressively increasing polarity of the extraction solvents. All extracts were analyzed by gravimetric analysis to determine the mass extracted, then separated by thin layer chromatography to determine the number of compounds present in each, and tested for antimicrobial activity in bioassays against Gram-positive and Gram-negative bacteria, as well as, several strains of fungi. Based on the preliminary data, toluene extract has shown antifungal activity against S. cervisae, whereas dichloromethane extract has shown antibacterial activity against Gram-positive bacteria S. aurentiace and M. leuteus.