Untargeted lipidomics-guided characterization of neuroprotective and neurotrophic activities of ethanol-modified supercritical carbon dioxide coffee pulp extracts.

Coffee pulp, an abundant by-product of coffee processing, was evaluated as a source of neuroactive lipids using ethanol-modified supercritical CO2 (sc-CO2); the resulting extract was compared with extracts obtained using ethanol and water. Untargeted lipidomics identified a total of 295 lipid species across all three extracts, spanning 22 classes, with glycerolipids predominating in all extracts (63.7-88.0%). The sc-CO2 and ethanol extractions yielded more diverse lipid profiles enriched in long-chain polyunsaturated triglycerides, whereas the water extract showed lower lipid coverage and higher proportions of saturated diglycerides. Differential lipids were linked with membrane organization, lipid signaling, and pathways related to neurotrophins and autophagy. The sc-CO2 extract showed the strongest acetylcholinesterase and butyrylcholinesterase inhibition before and after digestion, and its bioavailable fraction provided the greatest preventive cytoprotection in CuSO4-injured P19-derived neurons. The water extract increased brain-derived neurotrophic factor (BDNF) levels in unstressed neurons and was associated with specific diglycerides. This is the first study to show that sc-CO2 extraction effectively enriches neuro-relevant lipids from coffee pulp. These findings support the development of neuroprotective food ingredients from coffee by-products and promote coffee pulp valorization within the frameworks of the circular economy and the Sustainable Development Goals.