Effect of extraction temperature on the fatty acid composition, metabolic profile, and bioactivity-related properties of Lepidium sativum seed oil

Lepidium sativum L. (garden cress) seeds are a valuable source of oil rich in unsaturated fatty acids. This study examined the effect of extraction temperature on the yield, fatty acid composition, metabolic profile, and functional properties of L. sativum seed oil. Fixed oils were obtained by maceration in n-hexane at room temperature (cold-extracted seed oil, CSO) and by Soxhlet extraction in n-hexane at 70 °C (hot-extracted seed oil, HSO). Chemical characterization by GC–MS revealed marked differences between the two oils. α-Linolenic acid was the major fatty acid in CSO (36.04%), whereas oleic acid predominated in HSO (24.73%). The influence of these compositional changes on functional properties was assessed using DPPH radical-scavenging and α-amylase inhibition assays. CSO showed higher antioxidant activity (IC 50 = 138.47 ± 2.87 µg mL −1 ) and stronger α-amylase inhibitory activity (IC 50 = 123.46 ± 2.48 µg mL −1 ) than HSO. The results demonstrate that extraction temperature significantly affects the lipid composition of L. sativum seed oil and is associated with changes in its functional properties.