Extracts of the green algae Ulva prolifera possess antioxidant and antibacterial activities in vitro

Abstract

Macroalgae are currently being explored as novel and sustainable sources of bioactive compounds. Ulva prolifera is a major member of the green algae, as it includes various bioactive compounds, including carotenoids, fucoidans, and phlorotannins, with various biological activities in pharmaceutical, nutraceutical, cosmeceutical, and functional foods industries. In the current work, the rbcL gene products were utilized in identifying U. prolifera molecularly. The antibacterial and antioxidant activities of the hexane, ethyl acetate, and methanol extracts of U. prolifera were carried out In vitro. The total antioxidant capacity method was utilized in assessing the antioxidant activity. Estimation of nutritional value of U. prolifera showed 5.4±0.04%, 1.7±0.04% and 43±0.5% dry weight for total proteins, lipids, and carbohydrates, respectively. The total antioxidant capacity of algal hexane, ethyl acetate, and methanol extract was 0.97±0.09, 1.23±0.04 and 1.63±0.09 mg equivalent ascorbic acid/gdw, respectively. Investigation of the antibacterial activity of U. prolifera against Staphylococcus aureus and Aeromonas hydrophila showed that the recorded diameter of the inhibition zones for the methanolic extract was 1.1cm. The antibacterial effect of hexane extract against Edwardsiella tarda was high which had a diameter of 1.5cm. Of interest, the ethyl acetate extract of U. prolifera showed potent antibacterial activity against the three bacteria, including Vibrio anguillarum, Aeromonas hydrophila, and Edwardsiella tarda. These results indicate that macroalgae U. prolifera contain bioactive substances with potential antioxidant and antibacterial effects.