Chemical characterization, antiproliferative activity and molecular docking of bioactive compounds from brown algae Fucus spiralis

Abstract

Faced with the growing demands for natural products, the marine environment is a potential source for the discovery of therapeutic compounds. The aim of this study was to evaluate the in vitro cytotoxic potential of extracts and fractions obtained from brown algae Fucus spiralis collected on the Moroccan Atlantic coast. The ethyl acetate extract which showed the highest inhibition of A. salina viability (LC50 = 52.162 ± 3.058 μg/mL), was fractionated by silica column chromatography using different combinations of solvents. The bioactive fraction eluted with the ethyl acetate/ethanol solvent system (FAE6 system, 90:10 v/v) showed very significant antiproliferative activity (P ˂ 0.001) against cell lines HepG-2 (liver cancer), HT29 (cancer colon), MCF7 and BT-549 (breast cancer) with IC50 values of 4.36 ± 0.0008 μg/mL, 5.39 ± 0.002 μg/mL, 5.97 ± 0.058 μg/mL and 6.588 ± 0.005 μg/mL, respectively. The compounds present in the bioactive fraction were identified by GC/MS, and this includes 2-(4-biphenylylsulfonyl)-1,2,3,4-tetrahydroisoquinoline-3 carboxylic acid (isoquinoline alkaloid) and proanthocyanidin (polyphenolic compound) as the major constituents. These two compounds were identified for the first time in Fucus spiralis collected from the atlantic coast of Sidi Bouzid (El Jadida-Morocco). Molecular docking analysis showed that 2-(4-biphenylylsulfonyl)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid and proanthocyanidin strongly bind to 4PYP and 1TUB target receptors with binding energies of −10.5 and − 9.4 Kcal/mol, respectively. Consequently, these two compounds could play a primordial role in the level of antiproliferative activity. Fucus spiralis could be a new source of natural antitumor agents, producing proanthocyanidin and 2-(4-biphenylylsulfonyl)-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid as promising drug candidates in cancer therapy.