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

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 mu g/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 BT549 (breast cancer) with IC50 values of 4.36 +/- 0.0008 mu g/mL, 5.39 +/- 0.002 mu g/mL, 5.97 +/- 0.058 mu g/mL and 6.588 +/- 0.005 mu g/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.

Automated summary

This study evaluated the in vitro cytotoxic potential of compounds extracted from Fucus spiralis collected on the Moroccan Atlantic coast. The bioactive fraction showed significant antiproliferative activity against several cancer cell lines, and the major constituents were identified as an isoquinoline alkaloid and a polyphenolic compound. These compounds could be promising drug candidates in cancer therapy.