Optimisation and bioactivity evaluation of <i>Brassica rapa</i> L. seed oil extraction using novel green dimethyl ether extraction

L. seed oil using green dimethyl ether (DME) and response surface methodology, and analysed fatty acids by GC. Bioactivities were evaluated in LPS-stimulated RAW264.7 macrophages by measuring cell viability and pro-inflammatory mediators (NO, IL-6, TNF-α). Antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging), tyrosinase inhibition, and sensitisation potential were also assessed. GC identified 21 fatty acids, with unsaturated fatty acids accounting for 92.98%, dominated by erucic (47.43%), oleic (13.70%), and linoleic acids (13.15%). Under optimal conditions (5 MPa, 45 °C, 60 min), DME achieved a 31.72% yield, exceeding Soxhlet extraction (30.94%); even at 0.8 MPa, the yield remained 22.48%, indicating energy-efficient, sustainable extraction. This low-pressure, low-temperature DME approach links process parameters with bioactivities, supporting potential applications in cosmetics, functional foods, and pharmaceuticals.