Liver fibrosis is a condition characterized by the excessive buildup of scar tissue in the liver. This scarring occurs as a result of chronic liver damage, often caused by conditions such as hepatitis, alcohol abuse, certain metabolic disorders, genetic abnormalities, autoimmunity, and noninfectious diseases such as fatty liver which leads to liver fibrosis. Nanoparticles have gained attention in recent years as potential therapeutic agents for liver fibrosis. They offer unique advantages due to their small size, large surface area, and ability to carry drugs or target specific cells or tissues. Studies have suggested that nanoemulsions may enhance drug delivery systems, enabling targeted drug delivery to specific sites in the liver and improving therapeutic outcomes. In this study, we explore the protective and therapeutic values with phytochemical profiling of the used agro-wastes decaffeinated palm date seeds (Phoenix dactylifera L., PSC) coffee and caffeinated Arabic coffee seeds (Coffea arabica L.; ACS). Both ACS and PSC extracts were converted into nanoemulsion (NE) forms using the oleic acid/Tween 80 system, which was recruited for the purpose of treating a rat model with liver fibrosis. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to record the sizes, morphologies, hydrodynamic diameters, and ζ-potentials of the prepared NE-ACSE and NE-PSCE. Accordingly, the NE-ACSE and NE-PSCE imaged via TEM and their ζ-potentials were recorded at 20.7, 23.3 nm and −41.4, −28.0 mV, respectively. The antioxidant properties were determined with a DPPH scavenging assay. The synthesized NE-PSCE and NE-ACSE were employed to treat a rat model with CCl₄-induced liver fibrosis, to estimate the role of each emulsion-based extract in the treatment of liver fibrosis through recording inflammatory parameters, liver functions, antioxidant enzymes, and histopathological analysis results. The nanoemulsion forms of both ACSE and PSCE provided significant increases in antioxidant enzymes, reducing inflammatory parameters, compared to other groups, where liver functions were decreased with values close to those of the control group. In conclusion, both nanoemulsions, ACSE and PSCE, provided a new avenue as therapeutic approaches for liver diseases, and further studies are encouraged to obtain maximum efficiency of treatment via the combination of both extracts.

Spent coffee grounds (SCG) are agro-industrial waste that is generated in very large quantities and is an excellent potential source of bioactive compounds. This paper explored and compared conventional solvent extraction (CSE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) as eco-friendly approaches to recover phenolic compounds from SCG. Extraction efficiency, total phenolic content, antioxidant activity, and chlorogenic acid concentration were systematically measured. At first, MAE results surpassed the other methods and showed the highest extraction yield (25.31%) and total phenolic content (74.8 mg GAE), with chlorogenic acid being quantified at 42.1 mg g⁻ ¹ extract. The MAE extract showed a powerful antioxidant capacity with an IC₅₀ value in the DPPH test of 44.8 mg L⁻ ¹ . In order to assess the real usage of the product, the optimized MAE extract was used in protein bar formulations at different concentrations (0.5,1.0, and 2.0% w/w). Progressive increases in extract levels improved the antioxidant activity and final product phenolic content; nevertheless, sensory evaluation disclosed a drop in the consumer acceptability at concentrations exceeding 0.5% mainly due to a bitterness increase. Through 60 days of storage testing, antioxidant stability showed concentration-dependent variations. In conclusion, this work provides evidence that extracts from SCG through green extraction techniques can be effectively utilized in functional foods systems, only if the level of the formula is adjusted to provide a good balance between the functional and sensory properties. Graphical Abstract