From invasive nuisance to biotechnological asset: LC-MS/MS chemical profiling and pharmacological potential of ascidian Styela plicata from Albufeira Lagoon, Portugal.

The invasive ascidian Styela plicata represents a major biofouling challenge in mussel aquaculture systems but also a potential source of bioactive marine metabolites. This study explores the chemical and biotechnological potential of S. plicata collected from Albufeira Lagoon, Portugal, through LC-MS/MS profiling and biological activity assays. Three crude extracts (SP1, ethyl acetate, SP2, dichloromethane:methanol 2:1, and SP3, isooctane) were analyzed using LC-MS/MS, annotating 28 major metabolites across eight chemical families: lipids, nucleosides/nucleotides, amino acids, heterocycles, alkaloids/indole derivatives, carbohydrates, thioglucosides, and halogenated. While no antibacterial activity was observed against Staphylococcus aureus (MRSA, MSSA) or Escherichia coli, all extracts displayed significant antibiofilm effects, with SP3 achieving 89.24% inhibition of S. aureus biofilm formation at a minimum biofilm inhibitory concentration (MBIC) of 250 µg/mL with minimal impact on bacterial growth. Furthermore, SP3 exhibited cytotoxicity (<1% cell viability) against HCT-116 colorectal cancer cells. These findings demonstrate that S. plicata, an invasive pest, produces metabolites of biotechnological relevance, supporting its valorization within circular bioeconomy frameworks as a sustainable source of antibiofilm and cytotoxic agents.