Oxylipin Profiling in Selected Brown and Red Algae: Detection of Heterobicyclic Oxylipins, Plasmodiophorols and Ectocarpins in Phaeophyceae

GC-MS oxylipin profiling of brown and red algal thalli was performed. Brown algae (<i>Fucus distichus</i> and <i>Alaria esculenta</i>) were collected from the Barents Sea coastline nearby Teriberka, Murmansk region, Kola Peninsula, Russia, while other brown and red algae were sourced from the Pacific coast of the Russian Far East. Triols and δ-ketols (epoxyalcohol synthase products) were found in most brown and red algae. Several Heterokontophyta and Rhodophyta species possessed α-ketols (products of allene oxide synthase) and related <i>vic</i>-diols. Plasmodiophorols and ectocarpins (hydroperoxide bicyclase (HPB) products) were found only in brown algae from the Ectocarpales, Fucales, and Laminariales orders, not in brown algae from the Desmarestiales or Dictyotales orders, or in any red algae. Therefore, plasmodiophorol A and other HPB products could be used as chemotaxonomic markers for the classification of the separate orders of algae within Heterokontophyta. The in vitro incubations of <i>F. distichus</i> thalli with linoleic and α-linolenic acid resulted in the formation of α-ketols and the hydroperoxide bicyclase product, plasmodiophorol A.