Screening Antifungal and Antioxidant Activity of Macroalgae from SE Spain Highlights the Invader Rugulopteryx okamurae.

The Mediterranean Sea harbors a rich diversity of macroalgae with pharmacological potential. In this study, antioxidant and antifungal activities of methanol and ethyl acetate extracts from Rugulopteryx okamurae, Dictyota fasciola, Batophora sp., Codium fragile, and Palisada tenerrima from the southeastern coast of Spain were evaluated. R. okamurae, Batophora sp. and C. fragile are non-native. All extracts exhibited antioxidant activity, particularly those obtained with methanol. R. okamurae and Batophora sp. showed the highest activity, inhibiting the DPPH· radical by more than 40% at 1 mg/mL. Methanolic extracts of R. okamurae and P. tenerrima showed in vitro fungistatic activity against the banana plant pathogenic fungus Fusarium oxysporum f. sp. cubense tropical race 4. R. okamurae exhibited the highest antifungal activity, with inhibition values of 23.3% and 30.5% at 10 and 20 mg/well, respectively, while P. tenerrima showed moderate activity, and the remaining extracts had lower effects. LC-MS/MS analysis of R. okamurae revealed a diverse metabolite profile, including oxylipin-type metabolites and terpenoid-related compounds. These results indicate that macroalgae from the southeastern Spanish coast may represent a source of antioxidant and antifungal compounds and support the valorization of invasive biomass.