Rare fatty acids and lipids in plant oilseeds: occurrence and bioactivity

Lipids are biomolecules which are present in plants as general metabolites with different functions such as structural, protective and also as storage material. Plants produce a high number of different fatty acids: the most common structural types are long linear hydrocarbon chains, saturated or unsaturated with an even number of carbon atoms. In addition, plants accumulate rare fatty acids with reference to their occurrence and to their structures such as number and arrangement of unsaturated bonds, chain branches, type of functional groups, cyclic structures and halogenation. Their presence is limited in plant leaves, roots or stems, while they are mostly found as components of storage seed oils. The present review aims to describe the structural features of selected unusual rare fatty acids occurring in plants, their bioactivity and applications as pharmaceutical, cosmetic, food and non-food industrial products. Cyanolipids, a group of rare natural lipids containing a cyanogenic group in the molecule and only found in seed oils of a few plant species are also commented.