Wild Seeds as Sustainable Sources of C18-Series Bioactive Fatty Acids: Metabolic Diversity, Nutritional Value, and Functional Applications

Wild seeds constitute a taxonomically diverse and underexplored reservoir of C18-series bioactive fatty acids (BFAs) with significant nutritional, biomedical, and industrial relevance. This review integrates current knowledge on their lipid composition, metabolic architecture, and potential applications. Numerous wild taxa accumulate high levels of oleic, linoleic, α-linolenic, γ-linolenic, and stearidonic acids, while others synthesise structurally specialised compounds such as punicic, petroselinic, and sciadonic acids. These FAs, together with tocopherols, phytosterols, and phenolics, underpin antioxidant, anti-inflammatory, immunomodulatory, and cardiometabolic effects supported by in vitro and in vivo evidence. The occurrence of these unusual lipids reflects lineage-specific modulation of plastidial and endoplasmic-reticulum pathways, including differential activities of SAD, FAD2/3, Δ6- and Δ5-desaturases, elongases, and acyl-editing enzymes that determine the final acyl-CoA and TAG pools. Wild seed oils show strong potential for translation into functional foods, targeted nutraceuticals, pharmacologically relevant lipid formulations, cosmetic ingredients, and bio-based materials. However, their exploitation is constrained by ecological sustainability, oxidative instability of PUFA-rich matrices, antinutritional constituents, and regulatory requirements for novel lipid sources. This review positions wild seeds as high-value, underused lipid resources with direct relevance to health and sustainability. It underscores their potential to enhance nutritional security and offer alternatives to conventional oil crops.