Diversity in seed fatty acid composition and petal pyrrolizidine alkaloid content in Echium amoenum Fisch. & C.A.Mey. populations.

BACKGROUND: Echium amoenum Fisch. & C.A. Mey. is an important medicinal plant rich in unsaturated fatty acids and pyrrolizidine alkaloids. This study examined seed fatty acid composition, pyrrolizidine alkaloids, and antioxidant activity in petals of different Iranian Echium populations. A randomized complete block design with three replications was used. Plant extracts were prepared with acidified methanol (5% formic acid). Seed fatty acids were quantified using gas chromatography (GC), while petal pyrrolizidine alkaloids were analyzed with an Ultimate 3000 UHPLC system coupled o an Orbitrap Fusion mass spectrometer. The antioxidant activity of the extracts was evaluated via DPPH radical scavenging assays.

RESULTS: Seed oil content varied among populations collected from Fasa, Roodsar, Ghazvin, Sari, Vaznehsar, and Leron. In the first year, oil content ranged from 16.20% to 22.40%, with the highest value observed in the Leron population, whereas in the second year it ranged from 21.00% to 25.50%, with Sari showing the highest oil content. The major fatty acids identified in the seed oils during the first year were oleic acid 18.35%-19.40%, linoleic acid 23.80%-26.20%, and α-linolenic acid 32.30%-34.20%. In the second year, oleic acid 15.80%-19.30%, linoleic acid 21.55%-24.70%, and α-linolenic acid 32.34%-37.40% were the predominant fatty acids. Among the populations evaluated in the second year, Fasa exhibited higher contents of γ-linolenic and α-linolenic acids, Leron had the highest linoleic acid content, and Vaznehsar was rich in oleic acid (p ≤ 0.01). Population collected from Leron also exhibited the strongest antioxidant activity in petal (p≤0.01). On the other hand, the concentrations of echimidine N-oxide and intermedine N-oxide varied notably among petal populations. Population collected from Fasa and Roodsar exhibited high echimidine N-oxide levels in petal (p≤0.01) at the first year 1592.18 and 1255.91 µg kg⁻¹, respectively, which declined by more than 85% in the second year. Population collected from Sari showed greater stability 485.49 µg kg⁻¹, while intermedine N-oxide in petal remained consistently low and irregular across both years.

CONCLUSIONS: These findings reveal substantial diversity among Echium populations, reflected in the high unsaturated fatty acid content of seeds and strong antioxidant activity of petals. Notably, first-year Echium amoenum plants exhibited relatively higher levels of echimidine N-oxide in petals, which may pose potential food-safety concerns. In contrast, second-year plants contained significantly lower levels of this compound, suggesting that they may present a reduced risk for consumption and be more suitable for food-related applications. Nonetheless, the food-safety implications of pyrrolizidine alkaloid content warrant further investigation and should be assessed considering established legal limits and regulatory frameworks.