Assessment of mutagenic activity of phlorotannin-enriched extracts of three brown algal species

BACKGROUND: Phlorotannins are unique phenolic compounds produced by brown algae. Due to their considerable biological activity these metabolites are extensively studied in the context of medicinal applications. However, to date, no studies addressed potential genotoxicity of phlorotannins. AIM: The objective of this research is an assessment of mutagenic activity of intracellular and cell wall (CW) bound phlorotannins of three brown algal species. MATERIALS AND METHODS: Mutagenicity of phlorotannin extracts of Desmarestia aculeata, Fucus serratus, and Ectocarpus siliculosus was assessed by the Ames test, carried out using three tester strains of Salmonella typhimurium (TA97, TA98, and TA100) with and without metabolic activation. RESULTS: Intracellular phlorotannin extracts of all tested algae showed relatively low values of minimum inhibitory concentration against S. typhimurium (20–30 μg/ml), with extract of D. aculeata being the most toxic. Intracellular phlorotannins of F. serratus and CW-bound polyphenols of E. siliculosus demonstrated moderate mutagenic activity in the Ames test inducing frameshift mutations with the number of His+ revertants more than twice higher compared to the control. The phlorotannin extracts of D. aculeata showed no mutagenic activity. CONCLUSIONS: The brown alga D. aculeata may be regarded as a promising source of phlorotannins for medical applications, as its phlorotannin-enriched extracts have high antibiotic activity and are not mutagenic.