LAUSR

This study was conducted to extract essential oil from an edible seaweed, Undaria pinnatifida, and determine its chemical constituents, antibacterial and antioxidant potential. Gas chromatography and mass spectroscopy analysis of the U. pinnatifida essential oil (UPEO) revealed 26 volatile compounds comprising a total of 97.03%. Fatty acids such as tetradecanoic acid (31.32%) and hexadecanoic acid (22.39%) were present in the highest amount, followed by 3-hexen-1-ol (5.67%), erythritol (4.73%), 4-imidazolidinone (4.40%) and (9Z)-hexadec-9-enoic acid (4.37%). UPEO displayed potent antibacterial activity (9.5–11.0 mm inhibition zone), an MIC of 12.5–25.0 mg/mL and an MBC of 25.0 mg/mL. UPEO also exhibited strong hydroxyl radical scavenging (IC50 85.54 µg/mL), reducing power (IC0.5 178.82 µg/mL) and superoxide radical scavenging (IC50 260.89 µg/mL) potential. Taken together, these results indicate that UPEO could be an economical and safe resource for natural antioxidant and antibacterial compounds that can be utilized in food processing, cosmetics and pharmaceutical sectors. Practical Applications Seaweeds are a rich source of natural bioactive compounds with various medicinal properties. The essential oils extracted from an edible seaweed, U. pinnatifida, could serve as an alternative source of natural antioxidant compounds with the potential for use as food additives and in food preservation and cosmetics. Use of this compound could minimize the use of synthetic antioxidant compounds that trigger health hazards. Furthermore, the bioactive compounds present in the UPEO could serve as a source of natural antibiotics against both Gram positive and Gram negative pathogenic bacteria.