Supercritical carbon dioxide and ethanol-assisted extraction of bioactive compounds from Bourbon, Catimor, and Caturra coffee pulp for maximized antioxidant and therapeutic properties

Coffee pulp waste contains valuable bioactive components that are often discarded, leading to environmental impact. The optimum level of supercritical (50 % CO₂: ethanol) extraction (SFE) condition revealed the highest yield% and antioxidant activity assayed by 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) in coffee peel compared to hot water (85 °C), and 80 % ethanol. Additionally, the optimized SFE condition at 60 °C, 300 Bar, and 60 min showed the highest yield (p > 0.05), and antioxidant activity of Bourbon, Caturra and Catimor coffee pulp extracts (CPE). Cell-based experiments unveiled the fascinating biological effects of the CPE. Cytotoxicity in both RAW 264.7 and HepG-2 cells, indicating their potential to trigger apoptosis, all the while demonstrating anti-inflammatory properties. Among the different coffee varieties, Caturra consistently exhibited the highest level of biological activity. The Western blot analysis further elucidated the extracts' capacity to influence critical cellular markers linked to oxidative stress, inflammation, and antioxidant responses, with the unaltered NF-kB expression implying a targeted impact on specific cellular pathways. Therefore, SFE using 50 % CO₂: ethanol ratios could extract the maximum phytochemicals and impart excellent functional properties as a functional ingredient for food fortification.