Herpes Simplex virus 1 (HSV-1), responsible for the common cold sore, can also lead to serious infections in immunocompromised people. Current antiviral chemotherapies face obstacles including the toxicity of therapeutic molecules, interference with normal cellular metabolism, genetic variability and the incurable nature of latent infections. Therefore, the search for new treatments is a public health issue. Marine invertebrates have held great potential for finding novel antiviral compounds. Little is known, about the antiviral activities of compounds isolated from holothurians. In New Brunswick, holothurian is fished for its edible bodywall and muscle, but its processing generates high amounts of byproducts. In vitro evaluation of the anti-HSV-1 activity by cell viability was performed on nine hydrolysates obtained by enzyme-assisted extraction and four solvent extractions from aquapharyngeal bulb and internal organs of Cucumaria frondosa at an MOI of 0.001 ID50/cells. After 72 h, four enzymatic hydrolysates from the aquapharyngeal bulb presented effective antiherpetic activities (EC50, = 7.2-15.2 mu g/mL). After evaluation at a higher MOI (0.01 ID50/cells), the most efficient extract (Papain hydrolysate) was fractionated to identify the active fraction. The fraction superior to 100 kDa showed the highest antiherpetic activity (EC50: 18.2 mu g/mL). In conclusion, upgrading byproducts of sea cucumber fisheries offers new sources of bioactive molecules. (C) 2015 Elsevier Ltd. All rights reserved.