Background/Objectives: Marine-derived bioactive compounds have attracted increasing interest due to their potential antiviral properties. This study investigated in vitro antiviral activity of oil extracted from the green-lipped mussel (Perna canaliculus, GLM) and low-molecular-weight (LMW) fucoidan from Undaria pinnatifida against three human viruses in mammalian cell systems. herpes simplex virus-1 (HSV-1), respiratory syncytial virus (RSV), and SARS-CoV-2. These marine compounds were selected with the longer-term aim of evaluating their combination as a potential synergistic antiviral strategy. Methods: Antiviral efficacy was assessed using complementary assay platforms, including plaque reduction assays in mammalian cell systems and a lentiviral pseudovirus system delivering a bioluminescent reporter gene in HEK293/ACE2 cells pseudotyped with the SARS-CoV-2 spike glycoprotein. Cytotoxicity was assessed in parallel, and the selectivity index (SI) was calculated as the ratio of CC50 to IC50 for each compound and virus tested. Results: GLM oil showed potential antiviral activity against SARS-CoV-2 pseudovirus (SI > 6.20), with limited activity against RSV (SI > 3.48) and HSV-1 (SI > 2.28). In contrast, LMW fucoidan did not demonstrate antiviral activity against any of the tested viruses. Conclusions: These findings support further investigation of GLM-derived bioactive compounds as potential antiviral agents, including studies to elucidate their mechanisms of action and in vivo studies to confirm their antiviral efficacy. Combination studies were not pursued in the present work as both compounds require further optimisation individually; however, future studies should evaluate their combined antiviral potential, as synergistic or additive effects remain plausible.
Ebrahimi et al. (Sat,) studied this question.