Study on the chemical constituents of Desmarestia menziesii (Ochrophyta, Desmarestiales), an Antarctic seaweed

This study investigated the chemical composition of the Antarctic brown macroalga Desmarestia menziesii , collected from Penguin and Livingston Islands. Sequential extractions using hexane, dichloromethane, ethyl acetate, and methanol were performed, followed by GC-MS, NMR, IR, and mass spectrometry analyses. The hexane extract revealed the presence of sterols such as fucosterol, isofucosterol, 24-ethylcholesta-5,24(25)-dienol, and stigmasta-5,24(28)-dien-3β-ol, in addition to saturated and unsaturated fatty acids. Environmental contaminants, including phthalates and siloxanes, were also detected, highlighting the alarming spread of anthropogenic pollution even in remote Antarctic environments. The ethyl acetate extract contained aromatic meroterpenoids with recognized antioxidant, antimicrobial, and cytotoxic activities. The methanolic extract was predominantly composed of mannitol (over 50%), a polyol with osmoregulatory, cryoprotective, and antioxidant properties. These findings expand the current knowledge of the chemodiversity of Antarctic macroalgae and highlight the biotechnological potential of the identified metabolites, with promising applications in pharmaceuticals, cosmetics, functional foods, and biopreservation.