<i>In vitro</i> antibiofilm, antibacterial, antioxidant, and antitumor activities of the brown alga <i>Padina pavonica</i> biomass extract

Abstract

The antibiofilm, antibacterial, antioxidant, and anticancer activities of the methanolic extract of <i>Padina pavonica</i> L. were determined. Results deduced that the algal extract had a high biofilm formation inhibitory action done via crystal violet (CV) assay, to 88-99%. The results showed a strong antibacterial against the identified bacteria species. <i>Staphylococcus aureus</i>, <i>Enterococcus faecalis</i>, <i>Pseudomonas aeruginosa</i>, <i>Klebsiella pneumonia</i>, <i>Bacillus subtilis</i>, and the extract had moderate antibacterial activity against <i>Escherichia coli</i>, <i>Pseudomonas fluorescens</i> and <i>Streptococcus agalactiae</i>. The algal extract has a concentration-dependent DPPH radical scavenging activity (84.59%, with IC₅₀ = 170.31 µg/ml). The inhibitory percent of <i>P. pavonica</i> methanolic extract <i>in vitro</i> antiproliferative activity was 1.79-98.25% with IC₅₀ = 15.14 µg/ml against lung carcinoma. Phenols, terpenes, amino acids, alkaloids, flavones, alcohols, and fatty acids were among the metabolites whose biological actions were evaluated. In conclusion, for the first time, <i>P. pavonica</i> methanolic extract exhibited effective antibiofilm, antibacterial, antioxidant, and anticancer activities. .