Phytochemical profiling, antibacterial, and antibiofilm activities of Sargassum sp. (brown algae) from the Red Sea: ADMET prediction and molecular docking analysis

Brown algae from the Red sea are a rich source of bioactive molecules with high biological activities. The present work was aimed at studying the phytochemical composition of the methanol/water extract from Sargassum sp. collected from Al-Kharrar Lagoon (Red sea, Saudi Arabia). The antimicrobial and antibiofilm activities were tested against S. aureus (methicillin resistant/sensitive strains), E. coli, K. pneumoniae, S. epidermidis, and C. albicans strains. The obtained results showed that 2-pentadecanone, 6,10,14-trimethyl-, hexadecenoic acid, methyl ester, n-hexadecanoic acid, 1,2-benzenedicarboxylic acid, and mono(2-ethylhexyl) ester were the dominant compound in the methanol/water extract from Sargassum spp. extract. In addition, the same crude extract was effective against all tested microorganisms with a diameter of growth inhibition zone ranging from (10.67 +/- 0.58 mm) for methicillin sensitive-S. aureus to (44.67 +/- 1.15 mm) for S. epidermidis. Minimal inhibitory concentrations and minimal bactericidal concentrations ranged from 6.25-12.5 mg/L to 50->50 mg/mL, respectively. Interestingly, the tested methanol/water extract was able to inhibit the biofilm formation by Staphylococcus spp. strains in a concentration dependent manner, and the highest percentage was recorded at 12.5 mg/mL for S. epidermidis (82.35 +/- 0.03 %). These findings have been confirmed by in silico results, specifically the drug-ability, free binding energies and molecular interactions of the extract compounds with some targeted receptors. Potential antimicrobial and antibiofilm activities could be attributed to the Sargassum sp. for which the phytochemical compounds possessed promising drug-likeness and pharmacokinetic properties.