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

Abstract

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.

1. Introduction

Wild seeds, i.e., those produced by naturally occurring, non-domesticated plant species, are increasingly recognised for their potential as reservoirs of bioactive fatty acids (BFAs), which are essential for various health benefits. Wild seeds contain a diverse range of FAs, including linoleic (LA, 18:2n-6), oleic (OA, 18:1n-9), α-linolenic (ALA, 18:3n-3), palmitic (PA, 16:0), and stearic (SA, 16:0) acids, which contribute to their health-promoting properties [1,2,3]. Many wild seeds are rich in essential FAs (EFAs), such as omega-3 (n-3) and omega-6 (n-6), known for their anti-inflammatory and cardiovascular benefits [4,5]. Specific examples of seeds rich in OA, LA, and ALA include Moringa oleifera (Drumstick Tree), whose seed oil is high in OA (72.06%), making it a promising candidate for high-quality edible oil [6], and Rubus idaeus (Red Raspberry) seeds, which contain significant LA and ALA, which are beneficial for health [7].

Wild seeds also contain tocopherols and phenolic compounds, enhancing their antioxidant activity. For instance, Trifolium pratense (Red Clover) seeds are rich in α-tocopherol, boosting antioxidant potential [1], whereas the seeds from Acacia nilotica (Gum Arabic Tree) and Mucuna gigantea (Burny Bean) are being investigated for managing chronic diseases such as diabetes and cardiovascular disorders due to their bioactive compounds [8]. Additionally, wild seeds are important sources of proteins, vitamins, and minerals, further contributing to their nutritional value [4].

Comparatively, seeds from wild plants often exhibit higher nutritional value than cultivated varieties. For example, wild Centaurea raphanina subsp. mixta (Knapweed) contains higher levels of polyunsaturated FAs (PUFAs) and phenolic compounds than its cultivated counterparts [9]. The bioactive lipid components in wild seeds vary significantly across species, influencing their health benefits [1] and making them suitable for functional foods aimed at preventing and managing chronic diseases [5]. Some are also explored for biodiesel production due to their FA profiles, offering potential as renewable energy sources [10].

Wild seeds, though often overlooked, contain a rich diversity of C18 BFAs and antioxidant compounds with considerable nutritional, therapeutic, and biotechnological value. Their metabolic complexity offers opportunities to broaden the global lipid supply, reduce reliance on a small number of major oil crops, and identify novel oils with functional and industrial relevance—an increasingly important goal in the context of growing nutritional demands and climate pressures.

Despite this potential, major knowledge gaps remain. Understanding of the regulatory mechanisms governing lipid mobilisation, FA modification, and the biosynthesis of bioactive compounds during seed germination and development is still limited. In addition, systematic comparisons across taxa are scarce, constraining efforts to link seed ecology, metabolic strategies, and opportunities for biotechnological application.

This review, therefore, synthesises current insights into the lipid composition, metabolic pathways, and bioactive FA profiles of wild seed oils; evaluates their nutritional, therapeutic, and industrial significance; and highlights emerging analytical and genomic approaches that may facilitate their sustainable utilisation and conservation.

2. Methodology

This review followed the PRISMA-ScR and Joanna Briggs Institute frameworks for scoping reviews [11,12]. The process comprised four stages: defining the research question, systematic search, study selection, and data charting/synthesis.

2.1. Search Strategy and Databases

A systematic search was conducted in Scopus, Web of Science, PubMed, CAB Abstracts, ScienceDirect, and Google Scholar for studies published up to September 2025. Grey literature (FAO, CBD, WHO, and NGO reports) and reference lists of included papers were also screened. The search combined controlled vocabulary and keywords such as “wild edible seed(s)”, “wild seed species”, and “seed fatty acids”. Boolean operators and truncation ensured sensitivity across databases.

2.2. Inclusion and Exclusion Criteria

Eligible records met the following criteria: (i) original or review studies reporting on WEFs’ nutritional, phytochemical, ecological, cultural, or socioeconomic attributes; (ii) peer-reviewed or reputable grey literature; (iii) English-language sources; and (iv) explicit mention of wild, semi-domesticated, or underutilised seeds used by humans. Exclusion criteria were: studies lacking primary data or relevant context (e.g., ornamental species only), duplicate records, or articles focused solely on domesticated crops. The complete list of manuscripts used to carry out the study is detailed in the References section.

2.3. Screening and Data Extraction

Search results were imported into Zotero v6.0, where duplicates were removed. Two reviewers independently screened titles and abstracts; full texts were retrieved for potentially eligible papers. Disagreements were resolved through discussion until a consensus was reached. For each included study, data were extracted into an Excel matrix capturing: author(s), year, country/region, study type, target species, parameters analysed (nutritional, phytochemical, ecological, socioeconomic), and principal findings.

2.4. Quality Appraisal

Although scoping reviews do not exclude studies based on quality alone, methodological rigour was assessed using adapted criteria from the Mixed-Methods Appraisal Tool (MMAT) [13]. This ensured consistency in data interpretation and transparency in reporting.

2.5. Data Synthesis and Analysis

Quantitative results were summarised using descriptive statistics (frequency of taxa, nutrient ranges, FA concentrations). Qualitative data (traditional uses, cultural significance, bioactivity of FA) were analysed thematically. Findings were mapped across the four stages of the Nutrition Care Process (assessment, diagnosis, intervention, monitoring/evaluation) to visualise how AI, biotechnology, or traditional practices interface with WEF utilisation and conservation. Where possible, information on ecosystem services and livelihood outcomes was integrated to highlight system-level linkages.

2.6. Ethical Considerations

No human or animal subjects were involved. All secondary data were properly cited. Traditional knowledge examples were drawn exclusively from published sources, acknowledging community contributions and ethical clearances where applicable.

3. Seeds as Structured Nutrient Reservoirs

Seeds are highly specialised plant organs designed to ensure species perpetuation by serving as compact repositories of nutrients and genetic material. They provide an autonomous system that supports embryonic development, dormancy, and germination. Their internal organisation—comprising seed coat, endosperm, and embryo—facilitates the accumulation and mobilisation of storage compounds such as lipids, proteins, carbohydrates, and mineral nutrients [14,15]. Beyond their biological role, these reserves also determine the nutritional and functional value of seeds in human diets and industry [16].

3.1. Nutrient Storage in Seeds

During maturation, seeds synthesise and deposit large quantities of macromolecules that sustain the embryo during quiescence and germination [17]. Lipids are mainly stored as triacylglycerols (TAGs) in oil bodies (OBs) surrounded by a phospholipid monolayer stabilised by oleosin proteins [18]. These lipid reserves are the primary energy source during post-germinative growth [19].

Proteins accumulate in protein storage vacuoles (PSVs) or protein bodies, serving as nitrogen and sulphur reservoirs. They provide the amino acids required for enzyme synthesis and metabolic activation during germination [20]. Seed storage proteins also define nutritional quality by providing essential amino acids such as lysine and methionine [21].

Carbohydrates, notably starch, accumulate in amyloplasts and act as an energy buffer. For instance, quinoa (Chenopodium quinoa) stores starch mainly in the perisperm, while proteins and lipids are concentrated in the embryo and endosperm [22]. Leguminous cotyledons, such as those of Vigna radiata (Mung Bean), exhibit dense starch granules that mobilise rapidly upon germination [23].

The contrasting structural organisation of dicot and monocot seeds illustrates how tissue differentiation—particularly in cotyledons and endosperm—determines the localisation and efficiency of nutrient storage (Figure 1).

Minerals—including phosphorus, magnesium, potassium, and calcium—are stored as phytate (myo-inositol hexakisphosphate) in the aleurone or embryo [24,25]. These reserves maintain ionic equilibrium and serve as cofactors for enzymatic reactions.

In addition to macronutrients, seeds are reservoirs of bioactive phytochemicals such as flavonoids, sesamin, and phenolics that protect against oxidative stress [16,26,27]. Species like Nigella sativa (Black Cumin), Vitis vinifera (Common Grape), and Cucurbita pepo (Pumpkin) accumulate significant levels of these compounds, conferring both antioxidant and therapeutic properties.

3.2. Role of Nutrients During Germination

During germination, stored lipids are rapidly mobilised to fuel embryo growth and early metabolic activation before photosynthesis begins [14]. Gibberellin signalling from the embryo induces the aleurone layer to secrete lipases and other hydrolytic enzymes, enabling the breakdown of triacylglycerols into free FAs (FFA) and glycerol [15,28]. These FAs are subsequently oxidised or converted into bioactive lipid mediators that regulate membrane remodelling, stress responses, and signalling pathways essential for seedling establishment and adaptation [17,29].

In oil-rich seeds such as legumes, the cotyledons act as the primary site of lipid storage and mobilisation, releasing FAs that serve both as energy substrates and precursors for bioactive molecules during early development [30]. This coordinated lipid mobilisation underpins seed vigour and ensures metabolic flexibility in variable environments.

3.2.1. Nutrient Transport Mechanisms

In oil-rich wild seeds, nutrient accumulation is controlled by highly compartmentalised transport processes that regulate the movement of assimilates from maternal tissues into developing filial structures. Photoassimilates and other nutrients are delivered via the phloem and unloaded at specialised maternal–filial interfaces, where apoplastic and symplastic pathways govern nutrient fluxes during seed filling [31]. This spatial organisation is particularly relevant in wild species, which frequently develop under fluctuating environmental conditions and therefore require efficient allocation of limited resources.

Lipids are not transported into seeds as intact storage molecules but are synthesised in situ from imported precursors. Carbon skeletons derived from transported assimilates are converted into lipid precursors, including acyl-CoA and glycerol-3-phosphate, which are imported into plastids to support de novo FA synthesis. Within plastids, saturated acyl chains are generated and subsequently exported to the endoplasmic reticulum for desaturation, elongation, and assembly into triacylglycerols [32]. The molecular mechanisms underlying FA synthesis, acyl trafficking, and lipid assembly are discussed in detail in Section 5.

The integration of long-distance nutrient transport with plastidial and ER-based lipid metabolism enables oil-rich wild seeds to accumulate diverse and often unusual FA profiles. This coordinated regulation underpins both oil yield and lipid quality in wild taxa and contributes to their ecological adaptability and functional value [31,32].

Mineral nutrients are bound to organic acids and chelators for remobilisation during germination [24]. Such transport and compartmentalisation mechanisms guarantee the precise allocation of energy and micronutrients for embryo viability.

3.2.2. Seed Structure and Lipid Accumulation

The anatomical and biochemical organisation of seeds directly determines lipid yield and composition. The distribution of oil bodies, the activity of desaturases and elongases, and the efficiency of storage mobilisation shape both the physiological performance of the seed and the nutritional quality of its oil [33,34].

4. Bioactive Fatty Acids in Wild Seeds and Other Bioactive Components

Wild seeds are important reservoirs of BFAs and other lipid constituents that influence both plant metabolism and potential nutritional value. This section focuses on the physiological roles of BFAs and the variability of their composition across wild plant species [35,36,37].

4.1. Nutritional and Health Roles of Bioactive FAs

BFAs such as OA, LA, and ALA are central to human nutrition because they regulate membrane fluidity, immune balance, and cardiovascular health [38,39]. The human body cannot synthesise LA and ALA de novo, making them essential dietary components [37].

Some n-3 PUFAs are only found in genetically modified seeds [40], notably eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). These display anti-inflammatory and cardioprotective activities by modulating eicosanoid synthesis and down-regulating pro-inflammatory cytokines [41,42,43]. They improve endothelial function, reduce triglycerides, and lower the risk of coronary heart disease [38,39].

Short-chain FAs (SCFAs), such as butyrate, derived from microbial fermentation of dietary fibres, maintain intestinal barrier integrity and immunological tolerance [37]. In metabolic disorders, PUFA-rich diets elevate adiponectin secretion and attenuate systemic inflammation [44,45].

However, PUFAs are chemically unstable. Their oxidative susceptibility can be mitigated through modern technologies such as encapsulation, nanoemulsions, and antioxidant fortification, which enhance intestinal absorption and shelf life [46,47,48].

Balancing dietary n-6:n-3 intake is essential since Western diets often show excessive LA relative to ALA. Wild seed oils containing both, such as those from Rubus ulmifolius (Elmleaf Blackberry) and Ribes nigrum (Blackcurrant), can help correct this imbalance [35,36]. Thus, BFAs represent key nutritional molecules linking plant lipid metabolism with human health promotion.

4.2. Lipid Composition and Bioactive Compounds Profiles of Wild Seeds

Wild plant seeds provide a rich and under-explored diversity of lipid profiles. Their oils often rival or surpass those of conventional oil crops in both quantity and bioactivity [16,49].

4.2.1. Oil Yield and Composition

Some seeds accumulate high amounts of oil; for instance, the seeds of pumpkin species (Cucurbita spp.) contain up to 42.3% oil, dominated by LA and OA, along with tocopherols and β-sitosterol that contribute to oxidative stability [49,50]. On the other hand, n-6 and n-3 PUFA concentrations are very variable, reaching high concentrations in Suaeda albescens (White Sea-blite), which exhibits significant proportions of LA and ALA [51]. It is noteworthy that Arecaceae species display variable FA profiles, although medium-chain FAs (MCFAs) commonly dominate, whereas Rhynchosia minima (Least Snout-bean, Fabaceae) and Sapium sebiferum (Chinese Tallow Tree, Euphorbiaceae) accumulate long-chain PUFAs (LCPUFAs) suitable for food and industrial applications [52,53]. The proportion of lipids contained in various BFA-rich seeds, belonging to different botanical families, is indicated in Section 6.

4.2.2. Minor Bioactives

Tocopherols and phytosterols in wild seeds act as endogenous antioxidants and cholesterol-lowering agents [49,54]. For instance, Onosma microcarpum seeds combine 74–80% PUFAs with substantial α-tocopherol content [54]. Table 1 details the FA composition and minor bioactive components of selected wild plant seeds.

4.2.3. Taxonomic Diversity

The FA profiles of seeds have frequently been used to establish taxonomic categories [55,56,57]. This way, the oilseeds from P. granatum, P. ginseng, and G. soja contain distinctive FAs such as punicic, petroselinic, and ALA, respectively [58]. On the other hand, P. glabra and P. syriaca exhibit high OA:ALA ratios with elevated antioxidant capacity, while J. curcas yields over 50% oil, suitable for biodiesel obtainment [59]. Bioprospecting for new sources of FAs with profiles suitable for industrial and food uses is a frequent and necessary research task. For instance, wild seeds from Nigeria exhibit balanced protein, lipid, and mineral contents, underscoring their potential for food security [26]. Seeds rich in unusual FA are also frequently bioprospected. This way, seed oils rich in punicic or conjugated linolenic acids are valuable because they possess anti-inflammatory and antitumor activity [58], due to tocopherol- and sterol-rich fractions, which exert antioxidant and hypocholesterolemic effects [50].

Despite their promise, wild seed oils remain underutilised compared with major crops like soybean and sunflower. Expanding lipidomic and metabolomic analyses of wild taxa can uncover new bioactive compounds and support sustainable resource diversification [16,60]. Table 1 offers an overview of the high PUFA and bioactive content of selected wild seeds.

Table 1. Fatty Acid Composition and Bioactive Components of Selected Wild Plant Seeds.

Plant Species	Oil Yield (%)	Main Fatty Acids	Other Bioactive Components	References
Punica granatum (Pomegranate)	12.92	Punicic acid (79.64%), PA (3.29%), Stearic acid (2.43%)	Saponification number (192.91), FFA (0.20%), Peroxide value (3.03)	[58]
Panax ginseng (Asian Ginseng)	9–12	Petroselinic acid (>60%), OA (15–17%), LA (15–16%)	-	[61]
Glycine soja	-	ALA (20%), OA (44–46%), LA (42–44%)	Protein, Ascorbic acid, Carotene, Enzyme activities (SOD, CAT, POD, PPO, RNase, Acid phosphatase, Esterase, Amylase)	[62,63]
Onosma microcarpum	17.5–20.5	PUFAs (74–80%)	Tocopherols (18.2 mg/100 g), Sterols (77.5 mg/100 g)	[54]
Prunus virginiana (Chokecherry)	3.4–11.5	LA (27.9–65.6%), OA (19.7–61.9%), ALA (29.2–30.8%)	Tocopherols (595–2837 mg/kg), Sterols (β-sitosterol, Δ5-avenasterol, cycloartenol, campesterol, stigmasterol, gramisterol)	[64]
Torreya grandis (Chinese nutmeg yew)	17.68	LA, OA, Sciadonic acid	-	[65]
Pyrus glabra (Smoothleaf Pear)	33	OA (49.51%), LA (46.99%)	α-tocopherol (69.80 mg/100 g), Antioxidant activity	[66,67]
Pyrus syriaca (Syrian Pear)	26	LA (46.99%), OA (41.43%)	α-tocopherol (45.50 mg/100 g), Antioxidant activity	[67]
Jatropha Curcas (Physic Nut)	52–56	OA (44–46%), LA (42–44%), PA (4–6%), Stearic acid (3–4%)	-	[59]
Various Nigerian wild seeds	19–58.5	-	Protein (6.5–24.2%), Minerals (Mg, Fe, Zn, Mn, Ca, Na, K, P), Phytate (1043.6–2905.2 mg/100 g), Cyanide (3.7–6.4 mg/kg)	[26]

Table 1. Fatty Acid Composition and Bioactive Components of Selected Wild Plant Seeds.

Plant Species	Oil Yield (%)	Main Fatty Acids	Other Bioactive Components	References
Punica granatum (Pomegranate)	12.92	Punicic acid (79.64%), PA (3.29%), Stearic acid (2.43%)	Saponification number (192.91), FFA (0.20%), Peroxide value (3.03)	[58]
Panax ginseng (Asian Ginseng)	9–12	Petroselinic acid (>60%), OA (15–17%), LA (15–16%)	-	[61]
Glycine soja	-	ALA (20%), OA (44–46%), LA (42–44%)	Protein, Ascorbic acid, Carotene, Enzyme activities (SOD, CAT, POD, PPO, RNase, Acid phosphatase, Esterase, Amylase)	[62,63]
Onosma microcarpum	17.5–20.5	PUFAs (74–80%)	Tocopherols (18.2 mg/100 g), Sterols (77.5 mg/100 g)	[54]
Prunus virginiana (Chokecherry)	3.4–11.5	LA (27.9–65.6%), OA (19.7–61.9%), ALA (29.2–30.8%)	Tocopherols (595–2837 mg/kg), Sterols (β-sitosterol, Δ5-avenasterol, cycloartenol, campesterol, stigmasterol, gramisterol)	[64]
Torreya grandis (Chinese nutmeg yew)	17.68	LA, OA, Sciadonic acid	-	[65]
Pyrus glabra (Smoothleaf Pear)	33	OA (49.51%), LA (46.99%)	α-tocopherol (69.80 mg/100 g), Antioxidant activity	[66,67]
Pyrus syriaca (Syrian Pear)	26	LA (46.99%), OA (41.43%)	α-tocopherol (45.50 mg/100 g), Antioxidant activity	[67]
Jatropha Curcas (Physic Nut)	52–56	OA (44–46%), LA (42–44%), PA (4–6%), Stearic acid (3–4%)	-	[59]
Various Nigerian wild seeds	19–58.5	-	Protein (6.5–24.2%), Minerals (Mg, Fe, Zn, Mn, Ca, Na, K, P), Phytate (1043.6–2905.2 mg/100 g), Cyanide (3.7–6.4 mg/kg)	[26]

4.3. The Importance of the n-6/n-3 FA Ratio

Current literature shows that a high ratio of n-6/n-3 FAs causes progressive impairment of health. Such a ratio influences health by shaping how these FAs are metabolised, incorporated into membranes, and converted into signalling molecules. Because both n-3 and n-6 PUFAs compete for the same enzymes, a high ratio limits the formation of EPA and DHA and increases arachidonic acid (ARA, 20:4n-6)-derived mediators that promote inflammation, platelet activation, and vascular tension. In contrast, n-3 PUFAs generate less inflammatory eicosanoids and specialised pro-resolving mediators that help restore tissue homeostasis. Overall, a high dietary n-6/n-3 ratio favours pro-inflammatory and pro-thrombotic conditions and weakens metabolic and neural protection, whereas a lower ratio—mainly through greater n-3 intake—supports healthier immune, cardiovascular, and cognitive function. Therefore, improving this ratio is essential for proper brain function and to prevent cardiovascular diseases, arthritis, cancer, and inflammatory and autoimmune diseases [68,69].

However, commonly consumed oils are ineffective for the improvement of this ratio, considering that they usually contain LA as the more prominent FA. Thus, alternative oils based on an adequate content in the Δ6-desaturated FAs, GLA and SDA, such as blackcurrant oil (R. nigrum), are now available to consumers [70]. In addition, some wild plants become cultivated, e.g., Paterson’s curse (Echium plantagineum), from which a seed oil rich in Δ6-desaturated PUFAs—GLA, SDA and ALA—is obtained [70,71].

Edible wild plants could help to improve the above-exposed ratio. Seeds typically contain LA and ALA as the main FAs, although there are some exceptions. The following sections provide information about selected seed-producer species around the world, which constitute valuable sources of FAs.

5. Metabolism and Biosynthesis of C18 BFAs

C18 FAs form the metabolic backbone of plant lipid biosynthesis and are fundamental to both plant physiology and human nutrition. As major constituents of membranes and storage triacylglycerols, they serve as precursors for PUFAs, eicosanoids, and signalling molecules [33]. In human diets, OA, LA, and ALA are pivotal for cardiovascular, inflammatory, and neural health [72,73].

5.1. Overview of Fatty Acid Biosynthesis

The biosynthesis of C18 FAs follows a conserved sequence beginning in plastids and continuing in the endoplasmic reticulum (ER). In plastids, acetyl-CoA is converted to malonyl-CoA by acetyl-CoA carboxylase, and FA synthase elongates acyl-ACP intermediates to yield palmitoyl-ACP (16:0) and stearoyl-ACP (18:0), the latter formed by KASII [33]. Stearoyl-ACP is desaturated by stearoyl-ACP desaturase (SAD) to produce oleoyl-ACP (18:1Δ9), the key precursor for downstream PUFA synthesis (Figure 2).

Oleoyl groups can remain in plastids or be exported as oleoyl-CoA to the ER for further modification (Figure 3). In the ER, FAD2 inserts a Δ12 double bond to form linoleic acid (LA), while the plastid analogue FAD6 performs a similar function [74]. LA is then desaturated by FAD3 (ER) or FAD7/FAD8 (plastids) to generate ALA [72]. In species expressing Δ6-desaturase, LA and ALA may also be converted to GLA and SDA, a pathway characteristic of Boraginaceae and Grossulariaceae or engineered oilseeds [73,75]. These products can be elongated by FA elongases and desaturated at additional positions to yield LCPUFAs, although most higher plants lack complete biosynthetic capacity for these compounds [73].

Phosphatidylcholine (PC) in the ER acts as the central site for desaturation and acyl exchange. Newly formed FAs are esterified to PC, modified, and returned to the acyl-CoA pool through LPCAT-mediated acyl editing. The flux of acyl groups between PC and triacylglycerol (TAG) is controlled by enzymes such as DGAT and PDAT, determining the incorporation of unsaturated FAs into storage lipids [74]. These coordinated processes shape the final PUFA content, stability, and nutritional properties of seed oils.

5.2. Summary of C18 Fatty Acid Metabolism

The biosynthetic network of C18 FAs exemplifies the intersection between plant metabolism and nutritional biochemistry. In plants, these pathways regulate energy storage, membrane composition, and stress tolerance; in humans, they provide essential nutrients and precursors for bioactive lipids that sustain cardiovascular, immune, and neurological health.

6. Profiles and Functions of Major C18 Bioactive Fatty Acids

C18 BFAs (Figure 4) are LCFAs with 18 carbon atoms that play diverse roles in human physiology, nutrition, and health. Among them, OA, LA, ALA, GLA, and SDA are particularly significant as dietary components and precursors of bioactive lipids. These FAs are associated with cardiometabolic health, immune modulation, and anti-inflammatory properties, making them critical in both preventive nutrition and therapeutic strategies.

6.1. Oleic Acid (OA 18:1n-9)

OA, the predominant monounsaturated FA in olive oil, is central to the Mediterranean diet. It has been shown to improve lipid profiles by reducing LDL cholesterol and increasing HDL cholesterol [76]. Additionally, OA influences inflammatory pathways through modulation of NF-κB signalling, reducing oxidative stress and endothelial dysfunction [77]. Its role in improving insulin sensitivity also underpins its potential in managing metabolic syndrome and type 2 diabetes.

Table 2 summarises the FA composition of diverse wild seeds, emphasising species with elevated OA content.

Table 2. Fatty acid composition of selected OA-rich seeds from wild plants.

Family/Species		Fatty Acids (FA% of Total FAs)									References
	%Oil	16:0	18:0	18:1n-9	18:2n-6	18:3n-3	18:3n-6	18:4n-3	20:1n-9	22:1n-9
Anacardiaceae
Pistacia atlanticus (Atlas Pistachio)	15.3	13.1	2.3	50.7	29.8	0.6	-	-	0.3	-	[78]
Pistacia terebinthus (Terebinth)	41.2	21.6	2.1	46.9	21.7	0.7	-	-	0.2	-	[79]
Sclerocarya birrea (Marula)	53.0	14.6	8.8	67.4	5.9	0.9	-	-	-	-	[80]
Rosaceae
Prunus persica (Peach)	48.0	5.85	1.45	58.00	30.80	0.95	-	-	-	1.60	[81]
Prunus pedunculata (Long Peduncled Almond)	50.4	1.5	0.5	66.5	30.8	0.1	-	-	-	-	[82]
Prunus triloba (Flowering Almond)	46.3	1.8	0.5	73.1	23.8	0.1	-	-	-	-	[82]
Prunus mongolica (Mongolian almond)	49.5	2.4	0.8	65.3	31.1	0.1	-	-	-	-	[82]
Prunus tangutica (Tangut Cherry)	43.6	5.0	1.9	75.4	17.0	0.1	-	-	-	-	[82]
Prunus tenella (Russian Almond)	45.9	3.1	1.1	71.7	23.6	0.1	-	-	-	-	[82]
Prunus armeniaca (Apricot)	8.8	4.7	0.9	62.4	28.9	0.12	-	-	0.1	-	[83]
Pyrus glabra	33.0	7.9	2.8	49.5	37.5	0.2	-	-	-	-	[67]
Pinaceae
Pinus pinea (Stone Pine)	44.9	6.5	3.5	38.6	47.6	0.7	-	-	-	-	[84]
Poaceae
Avena fatua (Wild Oat)	1.4	23.4	3.3	40.9	29.5	-	-	-	-	-	[85]
Fabaceae
Bauhinia esculenta (Gemsbok Bean)	-	14.1	6.5	47.9	24.6	-	-	-	1.0	1.8	[86]
Meliaceae
Trichilia emetica (Natal Mahogany)	-	-	2.2	48.5	10.4	1.0	-	-	-	-	[86]
Myrtaceae
Myrcianthes pungens (Guabiyu)	57.0	25.9	5.3	57.0	9.6	0.2	-	-	1.9	-	[55]
Annonaceae
Rollinia sylvatica (Rollinia)	54.4	20.8	4.3	54.4	20.5	-	-	-	-	-	[55]
Boraginaceae
Pholistoma auritum (Fiesta Flower)	56.1	12.3	1.9	56.1	26	2.1	-	1.6	-	-	[87]

Table 2. Fatty acid composition of selected OA-rich seeds from wild plants.

Family/Species		Fatty Acids (FA% of Total FAs)									References
	%Oil	16:0	18:0	18:1n-9	18:2n-6	18:3n-3	18:3n-6	18:4n-3	20:1n-9	22:1n-9
Anacardiaceae
Pistacia atlanticus (Atlas Pistachio)	15.3	13.1	2.3	50.7	29.8	0.6	-	-	0.3	-	[78]
Pistacia terebinthus (Terebinth)	41.2	21.6	2.1	46.9	21.7	0.7	-	-	0.2	-	[79]
Sclerocarya birrea (Marula)	53.0	14.6	8.8	67.4	5.9	0.9	-	-	-	-	[80]
Rosaceae
Prunus persica (Peach)	48.0	5.85	1.45	58.00	30.80	0.95	-	-	-	1.60	[81]
Prunus pedunculata (Long Peduncled Almond)	50.4	1.5	0.5	66.5	30.8	0.1	-	-	-	-	[82]
Prunus triloba (Flowering Almond)	46.3	1.8	0.5	73.1	23.8	0.1	-	-	-	-	[82]
Prunus mongolica (Mongolian almond)	49.5	2.4	0.8	65.3	31.1	0.1	-	-	-	-	[82]
Prunus tangutica (Tangut Cherry)	43.6	5.0	1.9	75.4	17.0	0.1	-	-	-	-	[82]
Prunus tenella (Russian Almond)	45.9	3.1	1.1	71.7	23.6	0.1	-	-	-	-	[82]
Prunus armeniaca (Apricot)	8.8	4.7	0.9	62.4	28.9	0.12	-	-	0.1	-	[83]
Pyrus glabra	33.0	7.9	2.8	49.5	37.5	0.2	-	-	-	-	[67]
Pinaceae
Pinus pinea (Stone Pine)	44.9	6.5	3.5	38.6	47.6	0.7	-	-	-	-	[84]
Poaceae
Avena fatua (Wild Oat)	1.4	23.4	3.3	40.9	29.5	-	-	-	-	-	[85]
Fabaceae
Bauhinia esculenta (Gemsbok Bean)	-	14.1	6.5	47.9	24.6	-	-	-	1.0	1.8	[86]
Meliaceae
Trichilia emetica (Natal Mahogany)	-	-	2.2	48.5	10.4	1.0	-	-	-	-	[86]
Myrtaceae
Myrcianthes pungens (Guabiyu)	57.0	25.9	5.3	57.0	9.6	0.2	-	-	1.9	-	[55]
Annonaceae
Rollinia sylvatica (Rollinia)	54.4	20.8	4.3	54.4	20.5	-	-	-	-	-	[55]
Boraginaceae
Pholistoma auritum (Fiesta Flower)	56.1	12.3	1.9	56.1	26	2.1	-	1.6	-	-	[87]

Across taxa, OA predominates, particularly within Rosaceae and Anacardiaceae, where values frequently exceed 60% of total FAs. P. tangutica (75.4%), P. tenella (71.7%), and S. birrea (67.7%) demonstrate particularly high OA levels, comparable to conventional high-OS crops such as olive or avocado. These findings highlight the potential of certain wild Prunus species as alternative OA-rich oil sources, especially given their adaptability to arid or temperate zones.

Conversely, Anacardiaceae members (P. atlanticus and P. terebinthus) exhibit more balanced OA profiles (46.9–50.7% OA; 21.7–29.8% LA), suggesting a dual nutritional and oxidative stability benefit. Myrtaceae (M. pungens) and Annonaceae (R. sylvatica) also contain high monounsaturated proportions (54–57% OA), coupled with moderate saturated fractions (≤26% total of saturated FAs, SFAs), confirming their metabolic bias toward desaturation at Δ9.

In contrast, Poaceae (A. fatua) and Fabaceae (B. esculenta) display higher PA and LA contents, yielding less favourable OA:LA ratios. Overall, the table reveals a phylogenetic pattern where rosaceous and anacardiaceous seeds preferentially accumulate oleate, whereas species from Poaceae and Fabaceae maintain more polyunsaturated profiles. From an applied perspective, these OA-dominant wild seeds could represent promising raw materials for stable, nutritionally balanced edible oils suitable for breeding or sustainable oilseed diversification.

6.2. Linoleic Acid (LA, 18:2n-6)

LA is the most abundant dietary PUFA, being an EFA that must be obtained from food. LA is the precursor for ARA, which in turn gives rise to pro-inflammatory eicosanoids [88]. However, epidemiological evidence suggests that higher LA intake is associated with reduced risk of coronary heart disease [89]. Its physiological effects depend on the dietary balance of n-6 and n-3 LA, as excessive LA relative to n-3 intake may promote inflammation.

Table 3 dataset expands the compositional overview to other wild seeds without focusing exclusively on oleate dominance. Here, LA frequently dominates, particularly in A. retroflexus (61.5%), C. dentatus (66.2%), and C. depressa (48.3%). These taxa show the typical desaturation sequence of the LA biosynthetic pathway, reflecting their adaptive responses to warm or dry environments where high PUFA contents maintain membrane fluidity.

Table 3. Fatty acid profiles of LA-rich seeds from wild plants.

Family/Species				Fatty Acids (FA% of Total FAs)							Source
	Oil%	16:0	18:0	18:1n-9	18:2n-6	18:3n-3	18:3n-6	18:4n-3	20:1n-9	22:1n-9
Amaranthaceae
Amaranthus retroflexus (Pigweed)	7.2	9.7	2.0	23.3	61.5	1.1	-	-	-	-	[90]
Boraginaceae
Symphytum creticum (Cretan Comfrey)	47.1	10.7	3.1	17.0	39.0	1.3	23.2	0.7	2.1	1.1	[91]
Alkanna graeca (Greek Alkanet)	10.8	22.0	7.0	5.0	33.9	14.4	9.2	3.9	1.1	0.3	[91]
Amaranthaceae
Chenopodium album (Lamb’s Quarters)	9.1	8.4	0.9	20.7	56.3	6.5	-	-	-	-	[85]
Asteraceae
Carthamus dentatus (Toothed Thistle)	15.4	9.8	3.9	19.9	66.2	-	-	-	-	-	[92]
Centaurea depressa (Iranian Knapweed)	19.7	12.3	6.8	32.7	48.3	-	-	-	-	-	[92]
Pinaceae
P. pinea (Stone Pine)	44.9	6.5	3.5	38.6	47.6	0.7	-	-	-	-	[84]
Cucurbitaceae
Cucurbita pepo (Pumpkin)	-	13.1	5.7	24.9	54.2	0.12	-	-	-	-	[93]
Grossulariaceae
Ribes alpinum (Alpine Currant)	18.7	5.6	1.4	18.1	39.0	22.0	9.6	4.4	-	-	[70]
R. nigrum (Blackcurrant)	30.0	7.0	1.5	11.0	47.0	13.0	18.0	3.0	-	-	[70]
R. uva-crispa (Gooseberry)	18.0	7.5	1.0	17.0	40.0	19.5	11.0	4.5	-	-	[70]

Table 3. Fatty acid profiles of LA-rich seeds from wild plants.

Family/Species				Fatty Acids (FA% of Total FAs)							Source
	Oil%	16:0	18:0	18:1n-9	18:2n-6	18:3n-3	18:3n-6	18:4n-3	20:1n-9	22:1n-9
Amaranthaceae
Amaranthus retroflexus (Pigweed)	7.2	9.7	2.0	23.3	61.5	1.1	-	-	-	-	[90]
Boraginaceae
Symphytum creticum (Cretan Comfrey)	47.1	10.7	3.1	17.0	39.0	1.3	23.2	0.7	2.1	1.1	[91]
Alkanna graeca (Greek Alkanet)	10.8	22.0	7.0	5.0	33.9	14.4	9.2	3.9	1.1	0.3	[91]
Amaranthaceae
Chenopodium album (Lamb’s Quarters)	9.1	8.4	0.9	20.7	56.3	6.5	-	-	-	-	[85]
Asteraceae
Carthamus dentatus (Toothed Thistle)	15.4	9.8	3.9	19.9	66.2	-	-	-	-	-	[92]
Centaurea depressa (Iranian Knapweed)	19.7	12.3	6.8	32.7	48.3	-	-	-	-	-	[92]
Pinaceae
P. pinea (Stone Pine)	44.9	6.5	3.5	38.6	47.6	0.7	-	-	-	-	[84]
Cucurbitaceae
Cucurbita pepo (Pumpkin)	-	13.1	5.7	24.9	54.2	0.12	-	-	-	-	[93]
Grossulariaceae
Ribes alpinum (Alpine Currant)	18.7	5.6	1.4	18.1	39.0	22.0	9.6	4.4	-	-	[70]
R. nigrum (Blackcurrant)	30.0	7.0	1.5	11.0	47.0	13.0	18.0	3.0	-	-	[70]
R. uva-crispa (Gooseberry)	18.0	7.5	1.0	17.0	40.0	19.5	11.0	4.5	-	-	[70]

Notably, S. creticum and A. graeca (Boraginaceae) exhibit complex polyunsaturated patterns, including GLA and SDA, confirming this family’s characteristic Δ6-desaturase activity. Such profiles suggest potential nutraceutical applications, as these unusual n-3 and n-6 metabolites are precursors of eicosanoid biosynthesis. P. pinea and C. pepo illustrate contrasting compositions: the pine nut’s balanced OA:LA mixture (38.6:47.6%) supports oxidative stability, whereas pumpkin seed oil is markedly LA-rich (>54%).

The diversity captured here underscores that even among wild taxa, FA allocation mirrors phylogeny and ecological adaptation, ranging from monounsaturated FA (MUFA)-rich gymnosperms to PUFA-dominant herbs of open habitats. Collectively, these findings reinforce the nutritional potential of wild seeds as functional lipid sources, combining essential FAs with natural variability valuable for crop improvement.

6.3. α-Linolenic Acid (ALA, 18:3n-3)

ALA, an essential n-3 PUFA found in flaxseed, chia, and walnuts, serves as the metabolic precursor to EPA and DHA. Although the conversion rate is limited (often <10% for EPA and <5% for DHA), ALA still exerts independent cardioprotective and anti-inflammatory effects [94]. Increased dietary ALA intake has been linked to lower cardiovascular mortality and improved endothelial function [95].

Table 4 compiles representative species accumulating ALA and related highly unsaturated n-3 PUFA. The data reveals substantial taxonomic convergence toward ALA enrichment among Boraginaceae, Lamiaceae, and Linaceae, despite diverse ecological origins. B. arvensis and Echium species consistently exhibit >45% ALA, complemented by SDA levels up to 18%. This dual accumulation confirms the presence of both Δ6-desaturase and Δ15-desaturase pathways, making these species unique terrestrial sources of n-3 LCPUFAs precursors.

Among Lamiaceae, S. hispanica (Chia), P. frutescens, and L. iberica exhibit exceptionally high ALA contents (47–68%), aligning with their established functional-food status. The parallel occurrence of moderate LA suggests metabolic partitioning between n-3 and n-6 channels. In contrast, C. sativa and L. usitatissimum demonstrate balanced LA:ALA ratios (≈1:1), providing an optimal n-6/n-3 profile for human nutrition.

The inclusion of P. volubilis (Sacha inchi) and H. rhamnoides (Sea Buckthorn) highlights evolutionary diversification of n-3 metabolism beyond temperate herbs. Collectively, this table confirms that ALA-rich seed oils are widespread among unrelated lineages, providing a biochemical foundation for exploring novel n-3 crop species and for metabolic engineering targeting SDA biosynthesis.

Table 4. Fatty acid profiles of ALA-rich seeds from wild plants.

Family/Species	Oil (%)	Fatty Acids (FA% of Total FAs)									References
		16:0	18:0	18:1n-9	18:2n-6	18:3n-3	18:3n-6	18:4n-3	20:1n-9	22:1n-9
Boraginaceae
Buglossoides arvensis (Ahiflower)	~18–40 (cultivar dependent)	~6	~2	~12	~10.3	~48.5	~3.9	~18.6	trace	trace	[35]
Echium parviflorum (Small-flowered Bugloss)	12.7	6.6	3.0	8.0	10.1	47.6	7.1	17.3			[35]
Echium plantagineum (Paterson’s Curse)	~20–30	~6	~2–4	~16	~19	~30	~10	~13	—	—	[35]
Echium vulgare (Viper’s Bugloss)	—	—	—	~15–18	~18–22	~25–35	~8–12	~8–15	—	—	[35]
Brassicaceae
Camelina sativa (Camelina)	30–40	6–8	2–3	14–20	15–20	30–40	—	—	trace	trace	[96]
Cannabaceae
Cannabis sativa (Hemp)	25–35	6–12	2–4	8–20	~50–60	12–19	~2–4 (var.)	trace	trace		[97]
Elaeagnaceae
Hippophae rhamnoides subsp. rhamnoides (Sea buckthorn)	11.3	7.4	3.0	17.1	39.1	30.3	—	—	—	—	[98]
Euphorbiaceae
Plukenetia volubilis (Sacha Inchi)	30–55	~6	~2	7–10	~35	35–50	—	—	trace	trace	[99]
Lamiaceae
Lallemantia ibérica (Dragon’s Head)	30–38	6.5	1.8	10.3	10.8	68					[100]
Salvia hispanica (Chia)	30–35	5–7	2–3	6–8	20–26	~62.2	—	—	trace	trace	[101]
Perilla frutescens (Perilla)	18–43	3–6	1–3	9–20	10–24	47–64	—	—	trace	trace	[102]
Linaceae
Linum usitatissimum (Flax/Linseed)	35–45	6.6	4.4	18.5	17.3	53.2	—	—	trace	trace	[103]

Table 4. Fatty acid profiles of ALA-rich seeds from wild plants.

Family/Species	Oil (%)	Fatty Acids (FA% of Total FAs)									References
		16:0	18:0	18:1n-9	18:2n-6	18:3n-3	18:3n-6	18:4n-3	20:1n-9	22:1n-9
Boraginaceae
Buglossoides arvensis (Ahiflower)	~18–40 (cultivar dependent)	~6	~2	~12	~10.3	~48.5	~3.9	~18.6	trace	trace	[35]
Echium parviflorum (Small-flowered Bugloss)	12.7	6.6	3.0	8.0	10.1	47.6	7.1	17.3			[35]
Echium plantagineum (Paterson’s Curse)	~20–30	~6	~2–4	~16	~19	~30	~10	~13	—	—	[35]
Echium vulgare (Viper’s Bugloss)	—	—	—	~15–18	~18–22	~25–35	~8–12	~8–15	—	—	[35]
Brassicaceae
Camelina sativa (Camelina)	30–40	6–8	2–3	14–20	15–20	30–40	—	—	trace	trace	[96]
Cannabaceae
Cannabis sativa (Hemp)	25–35	6–12	2–4	8–20	~50–60	12–19	~2–4 (var.)	trace	trace		[97]
Elaeagnaceae
Hippophae rhamnoides subsp. rhamnoides (Sea buckthorn)	11.3	7.4	3.0	17.1	39.1	30.3	—	—	—	—	[98]
Euphorbiaceae
Plukenetia volubilis (Sacha Inchi)	30–55	~6	~2	7–10	~35	35–50	—	—	trace	trace	[99]
Lamiaceae
Lallemantia ibérica (Dragon’s Head)	30–38	6.5	1.8	10.3	10.8	68					[100]
Salvia hispanica (Chia)	30–35	5–7	2–3	6–8	20–26	~62.2	—	—	trace	trace	[101]
Perilla frutescens (Perilla)	18–43	3–6	1–3	9–20	10–24	47–64	—	—	trace	trace	[102]
Linaceae
Linum usitatissimum (Flax/Linseed)	35–45	6.6	4.4	18.5	17.3	53.2	—	—	trace	trace	[103]

6.4. γ-Linolenic Acid (GLA, 18:3n-6)

GLA is synthesised from LA (LA) by the enzyme Δ6-desaturase or obtained directly from borage, evening primrose, and blackcurrant seed oils. Unlike other n-6 PUFAs, GLA and its elongation product dihomo-γ-linolenic acid (DGLA, 20:3n-6) exhibit anti-inflammatory activity as precursors of series-1 prostaglandins [104]. Clinical evidence indicates that GLA supplementation can reduce symptoms of rheumatoid arthritis, atopic dermatitis, and other inflammatory disorders [105].

Table 5 shows the FA composition of wild seeds rich in GLA, identifying the Boraginaceae and Grossulariaceae as the main terrestrial sources of this bioactive n-6 PUFA. Within Boraginaceae, B. officinalis, B. morisiana, and B. pygmaea contain up to 20–25% GLA, confirming their importance as GLA producers. These oils combine high polyunsaturation with moderate LA, yielding balanced n-6/n-3 ratios and good oxidative stability.

Other Boraginaceae genera, such as Anchusa, Symphytum, Buglossoides, and Glandora show 12–23% GLA, often accompanied by SDA. This reflects Δ6-desaturase activity acting in both n-6 and n-3 pathways, making these taxa valuable biochemical models and potential gene donors for PUFA engineering. In Grossulariaceae, Ribes species (e.g., R. nigrum, R. diacanthum, R. komarovii) contain 13–25% GLA, constituting the principal non-Boraginaceae source. Their balanced LA and ALA levels ensure sufficient substrate for Δ6-desaturation, while cool climates favour GLA enrichment. Overall, these wild taxa demonstrate the limited but convergent capacity for GLA biosynthesis and highlight their potential as sustainable plant-based alternatives to marine or microbial sources.

Table 5. Fatty acid profiles of GLA-rich seeds from wild plants.

Family/Species	Fatty Acids (FA% of Total FAs)										Source
	Oil%	16:0	18:0	18:1n-9	18:2n-6	18:3n-3	18:3n-6	18:4n-3	20:1n-9	22:1n-9
Boraginaceae
Aegonychon purpurocaeruleum (Purple Gromwel)	10.0	7.5	2.2	9.4	22.3	33.9	17.5	7.2	-	-	[87]
Alkanna tinctoria (Alkanet)	31.8	8.7	2.2	13.5	28.5	29.4	13.0	3.3	-	0.9	[91]
Anchusa calcarea subsp. calcárea (Chalky Anchusa)	16.6	11.8	2.8	20.8	26.6	12.0	15.6	3.9	3.9	2.9	[106]
A. leptophylla subsp. incana (Slender Bugloss)	14.2	9.7	1.2	22.8	26.6	2.9	15.1	1.5	5.0	10.6	[106]
A. puechii (Puech’s Anchusa)	28.0	9.7	2.5	16.1	42.3	0.4	20.0	0.2	3.4	2.1	[106]
A. undulata subsp. undulata (Undulate Bugloss)	3.7	15.7	2.2	11.4	29.6	7.8	22.0	2.7	3.3	5.4	[106]
Borago morisiana (Starflower)	15.9	11.6	4.6	14.9	34.1	1.4	24.6	1.0	2.5	1.9	[75]
B. officinalis (Common Borage)	28.9	11.7	4.4	19.8	36.8	-	19.5	-	-	-	[35]
B. pygmaea (Corsican Borage)	21.9	14.0	6.7	20.0	27.4	1.3	22.9	1.2	2.8	1.9	[75]
Buglossoides incrassata (Gromwell)	10.7	9.3	2.7	8.7	19.8	31.6	13.8	6.0	1.8	-	[107]
Echium pininana (Giant Viper’s Bugloss)	26.9	7.0	3.3	11.5	13.0	34.5	17.1	11.7	0.2	-	[106]
E. sericeum (Blue Devil)	3.8	12.2	3.1	8.2	24.6	20.1	18.9	12.0	-	-	[35]
Glandora nitida (Viniebla azul)	9.6	12.3	3.1	16.4	22.6	17.0	19.2	8.7	1.0	-	[106]
G. prostrata subsp. Prostrata (Creeping Gromwell)	33.6	10.5	5.9	16.7	19.0	23.6	13.6	8.8	1.1	0.3	[106]
Lithodora maroccana (Purple Gromwell)	16.5	10.8	3.2	15.0	18.4	23.2	20.2	8.2	1.0	-	[108]
L. zahnii (Zahn’s Gromwell)	26.4	10.9	3.4	16.9	17.7	22.4	17.4	8.9	0.8	0.2	[91]
Myosotis nemorosa (Wood Forget-Me-Not)	19.9	13.2	3.9	20.8	30.8	4.7	20.3	1.6	2.6	1.2	[56]
Onosma polyphyllum (Golden Drops)	26.1	5.6	2.9	15.3	28.8	23.5	13.6	8.9	0.9	0.3	[87]
Pentaglottis sempervirens (Green Alkanet)	29.2	11.3	3.1	22.7	35.7	4.7	17.0	1.3	2.2	0.9	[106]
Symphytum bulbosum (Bulbous Comfrey)	39.8	13.4	2.1	10.6	30.7	9.2	26.2	2.8	1.7	1.0	[91]
S. caucasicum (Caucasian Comfrey)	34.3	8.2	2.7	24.6	34.0	2.0	22.9	0.6	2.2	1.1	[106]
S. creticum (Cretan Comfrey)	47.1	10.7	3.1	17.0	39.0	1.3	23.2	0.7	2.1	1.1	[91]
S. grandiflorum (Creeping Comfrey)	35.2	10.5	3.8	19.9	34.6	4.5	21.1	1.3	2.3	-	[87]
S. ibiricum (Iberian Comfrey)	6.3	12.4	3.7	22.3	32.2	4.2	18.9	1.2	2.1	0.9	[87]
S. tuberosum subsp. tuberosum (Tuberous Comfrey)	18.0	11.5	3.0	13.2	33.7	6.3	27.2	2.4	-	0.9	[87]
Grossulariaceae
Ribes alpinum (Alpine Currant)	16.0	7.8	1.8	10.3	44.2	15.8	15.3	3.3	0.9	-	[109]
R. diacanthum (Siberian Currant)	11.6	7.0	1.3	7.7	39.0	24.6	14.1	4.8	-	-	[57]
R. komarovii (Komarov’s Currant)	14.5	6.8	1.2	11.4	44.2	12.8	19.6	3.3	0.3	-	[109]
R. nigrum ‘Koksa’ (Blackcurrant)	12.7	8.2	1.7	10.9	38.8	15.1	17.0	3.8	-	-	[57]

Table 5. Fatty acid profiles of GLA-rich seeds from wild plants.

Family/Species	Fatty Acids (FA% of Total FAs)										Source
	Oil%	16:0	18:0	18:1n-9	18:2n-6	18:3n-3	18:3n-6	18:4n-3	20:1n-9	22:1n-9
Boraginaceae
Aegonychon purpurocaeruleum (Purple Gromwel)	10.0	7.5	2.2	9.4	22.3	33.9	17.5	7.2	-	-	[87]
Alkanna tinctoria (Alkanet)	31.8	8.7	2.2	13.5	28.5	29.4	13.0	3.3	-	0.9	[91]
Anchusa calcarea subsp. calcárea (Chalky Anchusa)	16.6	11.8	2.8	20.8	26.6	12.0	15.6	3.9	3.9	2.9	[106]
A. leptophylla subsp. incana (Slender Bugloss)	14.2	9.7	1.2	22.8	26.6	2.9	15.1	1.5	5.0	10.6	[106]
A. puechii (Puech’s Anchusa)	28.0	9.7	2.5	16.1	42.3	0.4	20.0	0.2	3.4	2.1	[106]
A. undulata subsp. undulata (Undulate Bugloss)	3.7	15.7	2.2	11.4	29.6	7.8	22.0	2.7	3.3	5.4	[106]
Borago morisiana (Starflower)	15.9	11.6	4.6	14.9	34.1	1.4	24.6	1.0	2.5	1.9	[75]
B. officinalis (Common Borage)	28.9	11.7	4.4	19.8	36.8	-	19.5	-	-	-	[35]
B. pygmaea (Corsican Borage)	21.9	14.0	6.7	20.0	27.4	1.3	22.9	1.2	2.8	1.9	[75]
Buglossoides incrassata (Gromwell)	10.7	9.3	2.7	8.7	19.8	31.6	13.8	6.0	1.8	-	[107]
Echium pininana (Giant Viper’s Bugloss)	26.9	7.0	3.3	11.5	13.0	34.5	17.1	11.7	0.2	-	[106]
E. sericeum (Blue Devil)	3.8	12.2	3.1	8.2	24.6	20.1	18.9	12.0	-	-	[35]
Glandora nitida (Viniebla azul)	9.6	12.3	3.1	16.4	22.6	17.0	19.2	8.7	1.0	-	[106]
G. prostrata subsp. Prostrata (Creeping Gromwell)	33.6	10.5	5.9	16.7	19.0	23.6	13.6	8.8	1.1	0.3	[106]
Lithodora maroccana (Purple Gromwell)	16.5	10.8	3.2	15.0	18.4	23.2	20.2	8.2	1.0	-	[108]
L. zahnii (Zahn’s Gromwell)	26.4	10.9	3.4	16.9	17.7	22.4	17.4	8.9	0.8	0.2	[91]
Myosotis nemorosa (Wood Forget-Me-Not)	19.9	13.2	3.9	20.8	30.8	4.7	20.3	1.6	2.6	1.2	[56]
Onosma polyphyllum (Golden Drops)	26.1	5.6	2.9	15.3	28.8	23.5	13.6	8.9	0.9	0.3	[87]
Pentaglottis sempervirens (Green Alkanet)	29.2	11.3	3.1	22.7	35.7	4.7	17.0	1.3	2.2	0.9	[106]
Symphytum bulbosum (Bulbous Comfrey)	39.8	13.4	2.1	10.6	30.7	9.2	26.2	2.8	1.7	1.0	[91]
S. caucasicum (Caucasian Comfrey)	34.3	8.2	2.7	24.6	34.0	2.0	22.9	0.6	2.2	1.1	[106]
S. creticum (Cretan Comfrey)	47.1	10.7	3.1	17.0	39.0	1.3	23.2	0.7	2.1	1.1	[91]
S. grandiflorum (Creeping Comfrey)	35.2	10.5	3.8	19.9	34.6	4.5	21.1	1.3	2.3	-	[87]
S. ibiricum (Iberian Comfrey)	6.3	12.4	3.7	22.3	32.2	4.2	18.9	1.2	2.1	0.9	[87]
S. tuberosum subsp. tuberosum (Tuberous Comfrey)	18.0	11.5	3.0	13.2	33.7	6.3	27.2	2.4	-	0.9	[87]
Grossulariaceae
Ribes alpinum (Alpine Currant)	16.0	7.8	1.8	10.3	44.2	15.8	15.3	3.3	0.9	-	[109]
R. diacanthum (Siberian Currant)	11.6	7.0	1.3	7.7	39.0	24.6	14.1	4.8	-	-	[57]
R. komarovii (Komarov’s Currant)	14.5	6.8	1.2	11.4	44.2	12.8	19.6	3.3	0.3	-	[109]
R. nigrum ‘Koksa’ (Blackcurrant)	12.7	8.2	1.7	10.9	38.8	15.1	17.0	3.8	-	-	[57]

6.5. Stearidonic Acid (SDA, 18:4n-3)

SDA, found in Boraginaceae oils and some algae, is a direct metabolic intermediate between ALA and EPA [70]. Unlike ALA, SDA bypasses the rate-limiting Δ6-desaturase step, resulting in more efficient EPA formation in the human body [70,110]. Supplementation with SDA significantly increases plasma EPA levels, supporting its role as a sustainable plant-derived alternative to fish oil [111]. This makes SDA particularly valuable for functional foods and nutraceuticals that enhance n-3 status.

Table 6 highlights SDA accumulation, a rare Δ6-desaturated n-3 FAs of high biological value. Data across Primulaceae and Boraginaceae reveal two evolutionary origins: (1) in Primula and Aleuritia, where SDA co-occurs with ALA and minor GLA, and (2) in Echium, Buglossoides, Glandora, and Lappula, which contain 15–22% SDA. B. arvensis (21.3%) and A. scotica (22.5%) are the richest terrestrial sources, rivalling some algal oils. High SDA levels often coincide with GLA, reflecting sequential Δ6- and Δ15-desaturation. Such dual enrichment supports Echium and Buglossoides oils as sustainable n-3 sources. SDA accumulation in P. macrophylla and A. scotica (>17–22%) suggests a role in cold adaptation. Overall, these findings underscore the biochemical versatility of wild seed lipids and identify Boraginaceae as a reservoir of valuable Δ6-PUFAs for future biotechnological exploration.

Table 6. Fatty acid composition of SDA-rich selected seeds of wild plants.

Family/Species	FA%/ Oil Content	16:0	18:0	18:1n-9	18:2n-6	18:3n-6	18:3n-3	18:4n-3	References
Primulaceae
Aleuritia scotica (Scottish Primrose)	-	7.7	0.4	10.3	26.9	2.2	29.0	22.5	[112]
A. farinose (Colicroot)	-	9.1	0.4	7.3	29.9	1.8	29.2	17.5	[112]
Primula macrophylla (Large Leaf Primrose)	-	9.9	1.1	18.2	7.3	0.8	55.4	17	[113]
P. sikkimensis (Sikkim Cowslip)	17.6	9.4	0.9	27.8	23.6	3.5	11.3	14.9	[114]
Boraginaceae
Buglossoides arvensis (Corn Gromwell)	15.0	8.9	2.3	7.6	11.6	7.4	40.9	21.3	[87]
B. arvensis subsp. Gasparrini (Corn Gromwell)	9.1	8.3	2.8	8.3	15.0	7.1	39.9	17.0	[107]
B. incrassate (Corn Gromwell)	14.0	10.1	2.9	8.1	12.3	6.7	39.9	19.9	[87]
Echium boissieri (Giant Viper’s Bugloss)	19.8	5.5	2.3	14.7	8.6	5.5	47.1	14.3	[56]
E. creticum (Cretan Viper’s Bugloss)	14.6	5.6	3	8.2	14.3	9.7	42.7	14.7	[56]
E. humile subsp. Pycnanthum (Blueweed)	7.5	5.8	2.3	12.8	18.7	10.9	34.8	16.2	[108]
E. parviloflorum (Small-flowered Viper’s Bugloss)	12.7	6.6	3.0	8.9	10.1	7.1	47.6	17.6	[35]
E. sabulicola (Sand Bugloss)	20.4	5.5	2.4	8.0	16.3	10.9	40.4	14.7	[56]
Glandora oleifolia (Shrubby Gromwell)	14.9	13.6	2.2	18.2	16.0	7.5	25.0	16.3	[87]
G. rosmarinifolia (Gromwell)	23.2	12.6	5.2	17.8	17.5	7.4	25.4	15.4	[87]
Lappula granulata (Stickseed)	12.7	5.3	1.9	16.1	11.7	6.9	32.6	17.7	[115]
L. intermedia (Stickseed	4.6	5.1	1.5	13.8	13.4	7.1	35.4	17.7	[115]
L. myosotis (Myosotis Lappula)	18	5.9	1.9	13.3	12.9	6.7	34.9	17.2	[115]
L. squarrosa (Bluebur)	12.2	10.2	7.8	12.2	13.6	7.3	27.6	17.1	[116]
Lithospermum arvense (B. arvensis synonym)	16.1	7	5.6	10.9	10.6	5.2	41.5	17.4	[117]
Rochelia disperma (Rochelia)	18	6	3	17	10	5	39	15	[117]
R. stylaris (Stickseed)	21	6	2	18	12	5	40	14	[117]

Table 6. Fatty acid composition of SDA-rich selected seeds of wild plants.

Family/Species	FA%/ Oil Content	16:0	18:0	18:1n-9	18:2n-6	18:3n-6	18:3n-3	18:4n-3	References
Primulaceae
Aleuritia scotica (Scottish Primrose)	-	7.7	0.4	10.3	26.9	2.2	29.0	22.5	[112]
A. farinose (Colicroot)	-	9.1	0.4	7.3	29.9	1.8	29.2	17.5	[112]
Primula macrophylla (Large Leaf Primrose)	-	9.9	1.1	18.2	7.3	0.8	55.4	17	[113]
P. sikkimensis (Sikkim Cowslip)	17.6	9.4	0.9	27.8	23.6	3.5	11.3	14.9	[114]
Boraginaceae
Buglossoides arvensis (Corn Gromwell)	15.0	8.9	2.3	7.6	11.6	7.4	40.9	21.3	[87]
B. arvensis subsp. Gasparrini (Corn Gromwell)	9.1	8.3	2.8	8.3	15.0	7.1	39.9	17.0	[107]
B. incrassate (Corn Gromwell)	14.0	10.1	2.9	8.1	12.3	6.7	39.9	19.9	[87]
Echium boissieri (Giant Viper’s Bugloss)	19.8	5.5	2.3	14.7	8.6	5.5	47.1	14.3	[56]
E. creticum (Cretan Viper’s Bugloss)	14.6	5.6	3	8.2	14.3	9.7	42.7	14.7	[56]
E. humile subsp. Pycnanthum (Blueweed)	7.5	5.8	2.3	12.8	18.7	10.9	34.8	16.2	[108]
E. parviloflorum (Small-flowered Viper’s Bugloss)	12.7	6.6	3.0	8.9	10.1	7.1	47.6	17.6	[35]
E. sabulicola (Sand Bugloss)	20.4	5.5	2.4	8.0	16.3	10.9	40.4	14.7	[56]
Glandora oleifolia (Shrubby Gromwell)	14.9	13.6	2.2	18.2	16.0	7.5	25.0	16.3	[87]
G. rosmarinifolia (Gromwell)	23.2	12.6	5.2	17.8	17.5	7.4	25.4	15.4	[87]
Lappula granulata (Stickseed)	12.7	5.3	1.9	16.1	11.7	6.9	32.6	17.7	[115]
L. intermedia (Stickseed	4.6	5.1	1.5	13.8	13.4	7.1	35.4	17.7	[115]
L. myosotis (Myosotis Lappula)	18	5.9	1.9	13.3	12.9	6.7	34.9	17.2	[115]
L. squarrosa (Bluebur)	12.2	10.2	7.8	12.2	13.6	7.3	27.6	17.1	[116]
Lithospermum arvense (B. arvensis synonym)	16.1	7	5.6	10.9	10.6	5.2	41.5	17.4	[117]
Rochelia disperma (Rochelia)	18	6	3	17	10	5	39	15	[117]
R. stylaris (Stickseed)	21	6	2	18	12	5	40	14	[117]

6.6. Unusual Fatty Acids

6.6.1. Metabolic Pathways

Unusual seed FAs arise through specialised modifications of common precursors such as oleic OA, LA, and ALA. These modifications include hydroxylation, conjugation, epoxidation, elongation, and cyclopropenation, catalysed by enzymes that are expressed specifically in developing seed tissues.

Hydroxy FAs (HFAs), such as ricinoleic (12-hydroxy-9-octadecenoic acid) in R. communis and lesquerolic (20:1-OH) in Physaria fendleri, result from hydroxylation of oleate at the Δ12 position by a FA hydroxylase (FAH12), followed by elongation (C18 → C20) in Lesquerella-type plants [118,119].

Epoxy FAs such as vernolic acid (cis-12,13-epoxy-9-octadecenoic acid) are synthesised via oleate 12,13-epoxygenase acting on LA, a mechanism elucidated in V. galamensis [75].

Conjugated triene FAs, such as α-eleostearic acid (9cis,11trans,13trans-18:3) and punicic acid (9cis,11trans,13cis-18:3), form through isomerisation of LA double bonds by conjugase enzymes [120,121].

Cyclopropene FAs (malvalic, sterculic acids) arise from cyclopropenation of OA catalysed by cyclopropene FA synthase, which introduces a cyclopropene ring [122].

Long-chain MUFAs (LCMUFAs) such as erucic acid (22:1n-9) are produced via FA elongases (FAE1-type) acting on OA [123].

Δ5-unsaturated polymethylene-interrupted FA (Δ5-UPIFA), found in Ephedra seeds, represents an ancient lineage of biosynthesis involving Δ5 desaturases uncommon in angiosperms [124].

Together, these modifications illustrate how seed oils become biochemical reservoirs of structurally diverse FAs with distinct physicochemical and biological properties.

6.6.2. Botanical Families and Distribution

The occurrence of unusual FAs is phylogenetically clustered:

-

Hydroxy FAs—Euphorbiaceae (R. communis) and Brassicaceae (P. fendleri);

-

Epoxy FAs—Asteraceae (V. galamensis) and some Euphorbiaceae;

-

Conjugated FAs—Euphorbiaceae (V. fordii), Lythraceae (P. granatum), and Cucurbitaceae (Momordica charantia);

-

Cyclopropene FAs—Malvaceae (Sterculia foetida), Bombacaceae, and Gossypium (trace);

-

VLCMUFAs—Brassicaceae (Brassica napus, B. juncea);

-

Δ5-UPIFA—Ephedraceae (Ephedra spp.);

-

Lauric acid (LaA, 12:0)—Arecaceae (Cocos nucifera, Elaeis guineensis).

This clustering indicates that unusual FA biosynthesis evolved multiple times as an adaptive specialisation—enhancing traits such as desiccation resistance, membrane fluidity, or antifungal defence [125].

Table 7 details seeds that produce structurally uncommon or bioactive FAs, expanding the chemical diversity of seed lipids far beyond nutritional roles. R. communis stands out for its hydroxylated ricinoleic (~90% of total FA), forming industrially valuable castor oil but also containing toxic lectins. Physaria species accumulate lesquerolic acid, a longer hydroxy analogue suitable for renewable lubricant production. Several taxa, including Vernicia and Parinari, synthesise conjugated trienes and tetraenes (eleostearic and parinaric acids) with notable antioxidant, anticancer, and drying-oil properties. V. galamensis exemplifies epoxy FA production (vernolic acid), while P. granatum yields punicic acid, a conjugated linolenic isomer with strong anti-inflammatory potential. Other notable groups include Sterculia species, rich in cyclopropene FAs, and Ephedra and Pinus with Δ5-unsaturated polymethylene-interrupted FAs (Δ5-UPIFAs), which confer unique biophysical and chemotaxonomic traits. Together, these examples demonstrate the metabolic innovation and evolutionary plasticity of wild oilseeds, many producing FAs with combined biological and industrial value.

Table 7. Unusual bioactive FAs in seeds.

Fatty Acid	Plant Source	Approx. % of Total FA in Seed Oil (Range)	Unusual/Bioactive Feature	Reference
Ricinoleic acid (18:1-OH, ricinoleate)	Ricinus communis (Castor)	~80–90% of oil FA	Hydroxylated FA (hydroxy group at C12); major HFA in castor oil—industrial uses and biological effects (laxative); seeds also contain toxic ricin.	[125]
Lesquerolic acid (20:1-OH)	Lesquerella/Physaria species	~30–65%; 25% seed oil	Hydroxy LCMUFAs (HFA family)—industrial HFA alternative to castor (lubricants, polymers).	[126]
α-Eleostearic acid (conjugated 18:3), 18:3Δ9cis, 11trans, 13trans	Tung tree (Vernicia/tung, e.g., Vernicia fordii), some Momordica (Bitter Gourd)	~69–83% (tung oil commonly reported ~70–83%; some studies cite ≈ 82–83%); 60% seed oil	Conjugated triene (drying oil) with bioactive/industrial properties (antioxidant/anticancer research; varnishes/paints).	[127]
α-Parinaric acid (conjugated 18:4) 18:4Δ9Z,11E,13E,15Z	Parinari laurinum (Makita), some Impatiens species, Sebastiana spp.	~29–48% (examples: Makita seeds ≈ 46%; Impatiens edgeworthii ≈ 29–48%).	Conjugated tetraene (fluorescent probe; antioxidant/antitumor activity in vitro); unusual polyene pattern.	[128,129]
Vernolic acid (epoxy-18:1)	Vernonia galamensis, some Euphorbiaceae	~61–80% (reported ranges; some accessions 61–80%).	Epoxy FA (epoxide functional group)—industrial value (resins, coatings); bioactivity noted.	[130]
Punicic acid (conjugated 18:3, α-CLnA)	Punica granatum (Pomegranate) seed oil	~55–84% (many cold-pressed oils report ~70–80%; some studies up to ~81–84%).	Conjugated linolenic isomer (CLnA)—strong reported bioactivities (anti-inflammatory, anticancer) in research studies.	[131]
Cyclopropene FA (sterculic, malvalic; CPE-FA)	Sterculia foetida (and some Malvaceae; traces in cottonseed)	Sterculic acid often 55–78% of seed oil in S. foetida; other species much lower (Cottonseed ~1% trace).	Cyclopropene ring in FA—highly unusual; toxic effects in animals, inhibit desaturase enzymes; destroyed by high-temp refining.	[132]
Δ5-unsaturated polymethylene-interrupted FA (Δ5-UPIFA), e.g., 5,11,14-20:3 and 5,11,14,17-20:4	Ephedra spp. (seeds of several Ephedra species) Seeds of Pinus species	Δ5-UPIFA): ~17–31% of total FA in Ephedra; ~3–40% in Pinus	Unusual Δ5 double bond position in methylene-interrupted systems—rare among higher plants. Δ5-UPIFAs have potential biomedical (anti-inflammatory effects) and nutritional applications.	[124,133]
Erucic acid (22:1n-9, VLC MUFA)	High-erucic rapeseed/mustard varieties	~20–54% in high-erucic cultivars (typical high-erucic rapeseed reports ~40–50% common); modern edible “canola” has very low levels.	LCMUFA—industrial uses (polymers, lubricants); toxic at high dietary intakes (hence low-erucic cultivars bred).	[134]
LaA, medium-chain SFAs (MCSFAs)	C. nucifera (Coconut), E. guineensis (Palm Kernel)	~45–55% of oil FA in coconut and Palm-Kernel oils (LaA is the major FA: ~45–50% Coconut; 45–55% Palm Kernel).	MCSFAs with antimicrobial properties—uncommon in temperate oilseeds but common in tropical kernel oils.	[135]

Table 7. Unusual bioactive FAs in seeds.

Fatty Acid	Plant Source	Approx. % of Total FA in Seed Oil (Range)	Unusual/Bioactive Feature	Reference
Ricinoleic acid (18:1-OH, ricinoleate)	Ricinus communis (Castor)	~80–90% of oil FA	Hydroxylated FA (hydroxy group at C12); major HFA in castor oil—industrial uses and biological effects (laxative); seeds also contain toxic ricin.	[125]
Lesquerolic acid (20:1-OH)	Lesquerella/Physaria species	~30–65%; 25% seed oil	Hydroxy LCMUFAs (HFA family)—industrial HFA alternative to castor (lubricants, polymers).	[126]
α-Eleostearic acid (conjugated 18:3), 18:3Δ9cis, 11trans, 13trans	Tung tree (Vernicia/tung, e.g., Vernicia fordii), some Momordica (Bitter Gourd)	~69–83% (tung oil commonly reported ~70–83%; some studies cite ≈ 82–83%); 60% seed oil	Conjugated triene (drying oil) with bioactive/industrial properties (antioxidant/anticancer research; varnishes/paints).	[127]
α-Parinaric acid (conjugated 18:4) 18:4Δ9Z,11E,13E,15Z	Parinari laurinum (Makita), some Impatiens species, Sebastiana spp.	~29–48% (examples: Makita seeds ≈ 46%; Impatiens edgeworthii ≈ 29–48%).	Conjugated tetraene (fluorescent probe; antioxidant/antitumor activity in vitro); unusual polyene pattern.	[128,129]
Vernolic acid (epoxy-18:1)	Vernonia galamensis, some Euphorbiaceae	~61–80% (reported ranges; some accessions 61–80%).	Epoxy FA (epoxide functional group)—industrial value (resins, coatings); bioactivity noted.	[130]
Punicic acid (conjugated 18:3, α-CLnA)	Punica granatum (Pomegranate) seed oil	~55–84% (many cold-pressed oils report ~70–80%; some studies up to ~81–84%).	Conjugated linolenic isomer (CLnA)—strong reported bioactivities (anti-inflammatory, anticancer) in research studies.	[131]
Cyclopropene FA (sterculic, malvalic; CPE-FA)	Sterculia foetida (and some Malvaceae; traces in cottonseed)	Sterculic acid often 55–78% of seed oil in S. foetida; other species much lower (Cottonseed ~1% trace).	Cyclopropene ring in FA—highly unusual; toxic effects in animals, inhibit desaturase enzymes; destroyed by high-temp refining.	[132]
Δ5-unsaturated polymethylene-interrupted FA (Δ5-UPIFA), e.g., 5,11,14-20:3 and 5,11,14,17-20:4	Ephedra spp. (seeds of several Ephedra species) Seeds of Pinus species	Δ5-UPIFA): ~17–31% of total FA in Ephedra; ~3–40% in Pinus	Unusual Δ5 double bond position in methylene-interrupted systems—rare among higher plants. Δ5-UPIFAs have potential biomedical (anti-inflammatory effects) and nutritional applications.	[124,133]
Erucic acid (22:1n-9, VLC MUFA)	High-erucic rapeseed/mustard varieties	~20–54% in high-erucic cultivars (typical high-erucic rapeseed reports ~40–50% common); modern edible “canola” has very low levels.	LCMUFA—industrial uses (polymers, lubricants); toxic at high dietary intakes (hence low-erucic cultivars bred).	[134]
LaA, medium-chain SFAs (MCSFAs)	C. nucifera (Coconut), E. guineensis (Palm Kernel)	~45–55% of oil FA in coconut and Palm-Kernel oils (LaA is the major FA: ~45–50% Coconut; 45–55% Palm Kernel).	MCSFAs with antimicrobial properties—uncommon in temperate oilseeds but common in tropical kernel oils.	[135]

6.6.3. Documented Uses and Health Relevance

Ricinoleic and lesquerolic acids are key industrial raw materials for lubricants, coatings, and biopolymers due to their hydroxyl group, which increases reactivity [119]. Vernolic acid is used as a natural epoxy feedstock in resins and paints, offering an eco-friendly alternative to petrochemical epoxides [136]. Eleostearic acid serves as a drying oil component in tung oil paints and varnishes due to its conjugated double bonds [137].

6.6.4. Nutritional and Biomedical Activities

Conjugated linolenic acids (CLnAs) such as punicic and α-eleostearic acids are bioactive and may improve lipid metabolism, reduce inflammation, and exhibit anticarcinogenic properties through PPAR and AMPK pathway modulation [121].

Punicic acid from pomegranate seed oil has demonstrated antioxidant, anti-inflammatory, and anti-obesity activities in rodent models and cell culture [138].

Cyclopropene FAs inhibit stearoyl-CoA desaturase (SCD1), reducing lipid synthesis, but are toxic at higher levels; low doses have shown metabolic regulatory potential [139].

LaA has antimicrobial and antiviral properties, contributing to immune-modulatory effects [140].

Erucic acid, in contrast, is associated with cardiac lipid accumulation at high intakes, prompting the development of low-erucic “canola” cultivars [141].

6.6.5. Synthesis and Implications

The metabolic engineering of unusual seed FAs represents both a challenge and an opportunity for biotechnology. HFAs, CLnAs, and epoxy FAs have inspired genetic engineering efforts to produce renewable industrial and nutraceutical oils [142]. However, health applications require careful toxicological evaluation—as some unusual FAs (e.g., cyclopropene, erucic) have demonstrated adverse effects.

From a nutritional standpoint, conjugated and hydroxy FAs show the most promise for beneficial biological effects, while from an industrial standpoint, epoxy and hydroxy FAs have established importance in bio-based materials and lubricants. Their evolutionary distribution also provides insights into lipid metabolic diversity and plant adaptation mechanisms.

7. Ethnobotanical and Industrial Relevance of Wild Seed Oils

Wild plant seeds have long held cultural and practical significance, serving as nutritional resources, traditional medicines, and raw materials for diverse industries. The growing recognition of their biochemical richness—particularly their content of BFAs, tocopherols, sterols, and phenolic compounds—has renewed scientific and commercial interest in these species [35,58]. Beyond their nutritional and pharmacological potential, wild seeds contribute to sustainable resource utilisation, bridging ethnobotanical heritage with modern applications in functional foods, cosmetics, and bioenergy.

7.1. Ethnobotanical Uses and Traditional Applications

In many indigenous and rural communities, wild seeds have historically been integral to dietary and medicinal practices. Their oils, decoctions, and powders are used to alleviate inflammation, digestive disorders, and cardiovascular ailments—benefits that are now supported by the presence of n-3 and n-6 FAs, phytosterols, and antioxidant tocopherols.

For example, M. oleifera seed oil, traditionally valued in South Asia and Africa for cooking and skincare, is rich in OA (~72%), providing both nutritional and emollient benefits [6]. On the other hand, A. nilotica and M. gigantea seeds are used in traditional medicine to manage chronic conditions such as diabetes and hypertension due to their bioactive lipid and phenolic composition [8]. Similarly, T. pratense (red clover) seeds, known in herbal medicine for their oestrogenic properties, contain α-tocopherol and other antioxidant compounds that support vascular health [1].

In the Mediterranean and Middle Eastern ethnobotanical context, wild Prunus, Pyrus, and Pistacia species have been cultivated for their seed oils used in culinary and therapeutic preparations. Oils from Prunus tangutica and P. tenella contain over 70% OA, comparable to olive oil, while P. terebinthus seeds yield an aromatic oil traditionally employed as a digestive tonic and topical remedy [79,82]. These examples illustrate how empirical knowledge of seed utility parallels contemporary biochemical evidence, validating traditional uses within a modern nutritional framework.

7.2. Functional Foods and Nutraceutical Development

The biochemical diversity of wild seeds makes them valuable candidates for the formulation of functional foods and nutraceuticals. Oils from species such as R. ulmifolius, R. nigrum, and B. arvensis combine high levels of PUFAs with natural antioxidants, offering balanced n-6/n-3 ratios conducive to cardiovascular and metabolic health [107,109].

Wild seeds enriched in GLA or SDA, particularly those from the Boraginaceae and Grossulariaceae families, are of special interest for anti-inflammatory dietary supplements. Clinical evidence supports GLA- and SDA-containing oils in the management of dermatitis, arthritis, and lipid metabolism disorders, making species such as B. officinalis, E. plantagineum, and R. nigrum promising sources for plant-based alternatives to marine oils [35,104].

Furthermore, seed oils rich in conjugated linolenic acids, such as punicic acid in P. granatum, have demonstrated antioxidant and anticancer potential, suggesting applications in preventive nutrition and therapeutic formulations [58]. The integration of these oils into functional products—fortified yoghurts, capsules, and emulsions—illustrates the intersection of traditional ingredients with modern food technology.

7.3. Industrial Applications: Biodiesel, Lubricants, and Green Chemistry

Beyond nutrition, wild seed oils are gaining attention as renewable feedstocks for industrial processes. Their chemical diversity, including unusual FAs (hydroxylated, epoxidised, and conjugated structures), provides unique physicochemical properties suitable for high-value bioproducts.

Species such as J. curcas, with oil yields of 52–56%, are recognised as viable sources for biodiesel production, providing an eco-friendly alternative to fossil fuels [59]. Similarly, S. sebiferum and V. galamensis produce oils rich in conjugated or epoxy FAs, useful for the synthesis of bio-based polymers, coatings, and lubricants [52,130].

Hydroxylated FAs found in R. communis and P. fendleri serve as precursors for bioplastics and high-performance lubricants, while conjugated FAs such as α-eleostearic and punicic acids offer antioxidant and drying properties advantageous in cosmetics and paints. These examples highlight the potential of wild seed lipids to replace petrochemical raw materials in green chemistry, fostering circular bioeconomy models.

7.4. Sustainability and Conservation Perspectives

The industrial and nutritional valorisation of wild seeds must proceed hand in hand with ecological stewardship. Many wild oilseed species inhabit fragile ecosystems where overharvesting or habitat conversion could threaten biodiversity. Sustainable exploitation requires strategies such as domestication of high-yield genotypes, controlled cultivation, and biotechnological propagation to ensure a consistent supply without compromising natural populations [60].

Moreover, comparative lipidomics and genomic characterisation can aid in identifying species with suitable FA profiles, enabling selective breeding for improved oil quality and environmental resilience. Promoting the use of underutilised local species can diversify agricultural systems, reduce dependence on monocultures, and enhance food security while preserving ethnobotanical knowledge.

In summary, wild seed oils occupy a pivotal position at the intersection of tradition, nutrition, and technology. Their ethnobotanical legacy, coupled with their biochemical and industrial potential, underscores their value as sustainable resources for human well-being and ecological innovation.

7.5. Challenges and Limitations

Despite their nutritional and industrial potential, several constraints limit the large-scale utilisation of wild seed oils. Many wild oilseed species occur in fragile ecosystems, where uncontrolled harvesting threatens biodiversity and degrades natural populations; sustainable valorisation therefore requires domestication, controlled cultivation, and biotechnological propagation to prevent overexploitation [60]. In addition, wild seeds often show high interspecific and geographic variability in oil content and FA profiles—for example, variable OA/LA/ALA ratios in Prunus and Pistacia spp. and substantial PUFA variation in Cucurbita spp. and S. albescens [49,50,51]—complicating standardisation for industrial supply chains. Several taxa also contain antinutritional or toxic compounds, including phytates, cyanogenic glycosides, and structurally unusual FAs; Nigerian wild seeds commonly exhibit elevated phytate and cyanide levels requiring processing for safe consumption [26], while cyclopropene FAs and erucic acid show dose-dependent toxicity that restricts their use in food applications [132,134]. Oils rich in PUFAs are additionally prone to oxidative instability, necessitating encapsulation or antioxidant fortification to preserve shelf life and nutritional quality, as highlighted in the context of PUFA stabilisation technologies [46,48]. Furthermore, extraction and refinement can be costly and technically demanding, particularly for species accumulating conjugated, hydroxylated, or epoxy FAs that require specialised processing despite their industrial relevance for polymers, lubricants, and coatings [52,130]. Regulatory approval presents another barrier: stringent safety and compositional standards slow market adoption, especially for oils containing potent bioactives such as punicic or petroselinic acids, which require thorough toxicological evaluation before commercialisation [131]. Finally, there remain important knowledge gaps in lipid mobilisation, FA modifications, and biosynthetic regulation in wild seeds; expanded comparative lipidomics and genomics are needed to support their effective domestication and biotechnological development [16,60]. Overall, these limitations underscore the need for integrated strategies combining sustainable resource management, metabolic and genetic characterisation, safety assessment, and process optimisation to realise the full potential of wild seeds in food, nutraceutical, and industrial sectors.

8. Conclusions and Future Perspectives

Wild seeds represent an abundant and diverse source of bioactive lipids, proteins, and antioxidants that are vital for human nutrition, health, and industry. Their chemical composition—rich in PUFAs, tocopherols, phytosterols, and phenolic compounds—provides high nutritional and therapeutic value. Many species display oil contents and FA profiles comparable to or surpassing those of commercial crops, yet remain underutilised. The results summarised here reveal that these seeds are not only evolutionary models of metabolic adaptation but also promising raw materials for sustainable innovation.

8.1. Opportunities for Food, Nutraceutical, and Pharmaceutical Industries

The lipid profile of wild seeds makes them valuable candidates for functional foods aimed at cardiovascular and metabolic health. Oils rich in LA, ALA, GLA, and conjugated ALA can serve as natural sources of EFAs with anti-inflammatory, antioxidant, and neuroprotective properties. Incorporating such oils into fortified foods, emulsions, or encapsulated formulations may enhance bioavailability and oxidative stability, meeting the growing demand for health-promoting dietary products.

In the nutraceutical sector, wild seed oils are potential ingredients for dietary supplements targeting chronic conditions such as obesity, diabetes, and cardiovascular disease. Their natural balance of n-6/n-3 PUFAs and the presence of tocopherols and phytosterols align with global health trends emphasising plant-based alternatives to marine or synthetic sources of bioactive lipids.

The pharmaceutical industry can benefit from the discovery of unusual FAs (e.g., punicic, eleostearic, and petroselinic) with antimicrobial, anticancer, and anti-inflammatory effects. The diversity of lipid structures among wild taxa represents a vast, largely untapped chemical space for novel drug leads and cosmeceutical formulations.

In addition, high oil-yielding wild species, including J. curcas, S. sebiferum, and V. galamensis, offer industrial applications as renewable feedstocks for biodiesel, lubricants, and biodegradable polymers, strengthening the circular bioeconomy and reducing reliance on petrochemical resources.

8.2. Future Directions and Sustainability

To fully realise this potential, interdisciplinary strategies are essential. Research on metabolic engineering and synthetic biology can optimise Δ6-desaturase and acyl-editing pathways, enhancing the production of GLA and SDA in promising taxa. Comparative genomics and metabolomics will continue to identify genes and pathways associated with lipid diversity, enabling precision breeding for desired traits.

Evaluating the cultivation potential of wild oilseeds under diverse environmental conditions can facilitate domestication and support sustainable agriculture in marginal ecosystems. Integrating wild species into local cropping systems enhances agroecological diversity while conserving genetic resources.

Future progress in sustainably exploiting wild seed oils will rely on combining ecological stewardship with targeted molecular innovation. Key families for metabolic engineering include Boraginaceae (Echium, Lappula) for n-6 and n-3 oils, Euphorbiaceae (Ricinus, Vernicia) for hydroxylated and conjugated FAs, Brassicaceae (Lepidium, Physaria) for elongated MUFAs and HFAs, Lythraceae (Punica) for conjugated linolenic acids, and Asteraceae (Vernonia) for epoxy-rich oils. Developing high-quality genomes and functional annotations for these taxa will accelerate the discovery of desaturases, elongases, and acyl-editing enzymes underpinning their unique lipid profiles. Establishing a wild oilseed lipidomics database, integrating FA compositions, TAG structures, and ecological metadata, would provide a central platform for breeding, domestication, and synthetic-biology efforts. Complementary advances in climate-resilient cultivation and community-based resource management will help ensure that new wild oilseed value chains are both innovative and environmentally responsible.

Finally, conservation programmes—both ex situ and in situ—are critical to preserving the genetic and biochemical diversity that underpins these applications. By combining traditional ethnobotanical knowledge with modern biotechnological approaches, wild seeds can be transformed into key resources for the food, nutraceutical, and pharmaceutical industries, while promoting environmental sustainability and global health.