Purification-Driven Modulation of Polyphenol Profile and Protein Glycation-Inhibitory Potential of Actinidia arguta and Actinidia kolomikta Fruit Extracts

This study characterises the polyphenol profile (LC-MS), antiglycation (BSA-GLU, BSA-FRU, BSA-MGO), and antioxidant potential (ABTS, DPPH) of A. arguta ('Scarlet September Kiwi') and A. kolomikta ('Lande') fruit before and after extract purification. A total of 48 polyphenols belonging to 11 chemical groups were identified. Crude Scarlet extract showed higher TPI (1079.51 µg/g dw) than the crude Lande (761.13 µg/g dw), with quercetin glucoside accounting for 71% of TPI. Crude Lande extract was dominated by caffeic acid glucoside (39% TPI). Purification markedly increased TPI values to 4082.13 µg/g dw (Scarlet) and 2550.51 µg/g dw (Lande). The crude extracts more effectively inhibited glucose- and fructose-induced protein glycation (IC₅₀ = 1.81-7.71 mg/mL) than methylglyoxal-mediated glycation (IC₅₀ = 14.33-24.26). Purification significantly enhanced antiglycation efficacy in all models (IC₅₀ = 0.47-1.78), as well as antioxidant capacity (IC₅₀ = 0.10-0.67 mg/mL). Statistical analyses revealed a strong alignment between the glycation-inhibitory activity and the tested antioxidant potential. These findings suggest that targeted purification enhances the functional potential of Actinidia species, making them promising sources of bioactive compounds against oxidative stress and protein glycation-related disorders.