Comparative phytochemical characterization and in vitro biological activities of coffee (Coffea arabica) and loquat (Eriobotrya japonica) seed extracts

The growing demand for natural bioactive compounds has intensified research into plant-derived extracts as plant-derived extracts as sources of bioactive compounds. Coffee ( Coffea arabica ) and loquat ( Eriobotrya japonica ) seeds represent underutilized sources of phytochemicals with potential health benefits, yet a direct comparative evaluation of their multi-target bioactivities remain limited . The objectives were to comparatively assess the phytochemical profiles with antidiabetic, antioxidant, butyrylcholinesterase (BChE) inhibitory activity, antimicrobial, and cytotoxic potentials of coffee and loquat seed ethanol extracts against Caco-2 colorectal cancer cells. Total phenolics, flavonoids, alkaloids, and terpenes were quantified by colorimetric assays, while different phenolic ingredients were examined by HPLC. Antioxidant activity was evaluated using DPPH and ABTS radical-scavenging assays. α-Glucosidase and α-amylase inhibition assays were utilized for antidiabetic action, while butyrylcholinesterase inhibition assay was utilized for the extract. Antimicrobial and anti-biofilm activities were tested against pathogenic bacteria and Candida albicans ; and cytotoxicity was assessed on Caco-2 (cancer) and Wi38 (normal) cells. Coffee seed extract contained significantly higher levels of total phenolics (172.46 ± 7.17 mg GAE/g), flavonoids (157.36 ± 3.34 mg QuE/g), and chlorogenic acid (63,681.37 ± 1,245.6 µg/g). It exhibited stronger antioxidant (DPPH IC₅₀ 0.66 ± 0.03 µg/mL; ABTS IC₅₀ 0.42 ± 0.02 µg/mL), antidiabetic (α-glucosidase IC₅₀ 10.20 ± 0.15 µg/mL), anti-Alzheimer (BChE IC₅₀ 3.20 ± 0.08 µg/mL), activity against the tested reference strains (MIC 7.8 µg/mL against S. aureus ), and differential cytotoxicity against Caco-2 cancer cells (IC₅₀ 78.5 ± 0.2 µg/mL) with lower toxicity to normal Wi38 fibroblasts (IC₅₀ 181.3 ± 2.2 µg/mL) under the conditions tested. This resulted in a preliminary selectivity index of 2.31, suggesting differential cytotoxicity that warrants further investigation. Loquat extract showed moderate but noteworthy activity, particularly against C. albicans (94.12 ± 0.8% biofilm biomass reduction (%) at 75% MBC). Coffee seeds show promising multifunctional bioactivities in vitro, warranting further investigation. Loquat seeds demonstrate moderate but noteworthy anti-Candida activity, suggesting potential for further fractionation and characterization.