The edible seaweed Laminaria japonica contains cholesterol analogues that inhibit Lipid Peroxidation and Cyclooxygenase Enzymes

Abstract

AbstractIn this study, 5 sterols were isolated and purified from Laminaria japonica, commonly known as edible brown seaweed, and their structures were identified based on detailed chemical methods and spectroscopic analyses. Spectroscopic analyses characterized 5 sterols as 29-Hydroperoxy-stigmasta-5,24(28)-dien-3β-ol, saringosterol (24-vinyl-cholest-5-ene-3β,24-diol), 24-methylenecholesterol, fucosterol (stigmasta-5,24-diene-3β-ol), and 24-Hydroperoxy-24-vinyl-cholesterol. The bioactivities of these sterols were tested using lipid peroxidation (LPO) and cyclooxygenase (COX-1 and −2) enzyme inhibitory assays. Fucosterol exhibited the highest COX-1 and −2 enzyme inhibitory activities at 59 and 47%, respectively. Saringosterol, 24-methylenecholesterol and fucosterol showed higher LPO inhibitory activity at >50% than the other compounds. In addition, the results of molecular docking revealed that the 5 sterols were located in different pocket of COX-1 and −2 and fucosterol with tetracyclic skeletons and olefin methine achieved the highest binding energy (−7.85 and −9.02 kcal/mol) through hydrophobic interactions and hydrogen bond. Our results confirm the presence of 5 sterols in L. japonica and its significant anti-inflammatory and antioxidant activity.Graphical abstractHighlightsSterols 29-hydroperoxy-stigmasta-5,24(28)-dien-3β-ol and 24-hydroperoxy-24-vinyl-cholesterol are identified for the first time in L. japonica.Saringosterol, 24-methylenecholesterol and fucosterol showed strong LPO inhibitory activity.Fucosterol showed highest binding affinity for COX-1 and −2 enzymes through hydrophobic interactions.