Biological activity of extract from Styela plicata and Ascidia mentula (Ascidiacea)

The biological activity of extract obtained from the ascidians Styela plicata and Ascidia mentula, living in the coastal lake Faro (Messina, Italy) was ascertained with specific regard to cytotoxic effect, tested on cultured human embryonic kidney (HEK 293 Phoenix) cells after 12, 24 or 48 h, and to antimicrobial effect (10 mg/mL), assayed on both Gram positive and negative strains. Nitrosative stress, possibly induced by the extract on HEK 293 cells and assessed by NO₂ ^–/NO₃ ^– production measurement, was also verified. With regard to cytotoxic activity, A. mentula extract was more effective than S. plicata one, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, with toxic action due to nitrosative stress. S. plicata extract had a more significant antimicrobial activity than A. mentula. The present findings provide a first evidence of the biological power exhibited by both S. plicata and A. mentula extracts, thus increasing the knowledge about the biological activity of marine compounds and providing novel information to possibly correlate the different toxicity pattern displayed by both specimens and their distribution in the lake Faro (Messina).