Frailty syndrome (FS) is a critical factor associated with several oxidative stress and age-related diseases. In this work, we investigated the connection between frailty, defined at early stages using a new cut-off value of the Frailty Trait Scale (FTS-5), and plasma biomarkers of oxidative stress. Plasma samples of 76 older women were analyzed to determine free and protein-bounded tryptophan (Trp), kynurenine (Kyn), N-formylKynurenine (N-Kyn), advanced glycation end products, and protein carbonylation. A subgroup of 30 subjects was selected from the entire group to determine malondialdehyde (MDA), free methionine (Met), phenylalanine (Phe), Trp, and Kyn. In the whole group (N = 76), Kyn and the Kyn/Trp ratio were higher in women with a Romberg test altered (p-values = 0.0439, and 0.0472, respectively) and BMI < 25.3 kg/m2 (p-values = 0.0008, and 0.0011, respectively). Increased protein carbonylation was found for subjects with BMI ≥ 25.3 kg/m2. For the subgroup, an increase in the Kyn/Trp ratio was observed in subjects with an altered Romberg test, concomitant with decreased levels of Trp, Met, Phe, and MDA (p-values = 0.0255, 0.0427, 0.0459, and 0.0173, respectively) when data were grouped according to the modified FTS-5. These results highlight the relevance of oxidative biomarkers as a tool for an early diagnosis of FS and its related complications.
© 2026. The Author(s).