Competitive reactions between additives and probes towards peroxyl radicals (ROO^•) are usually employed to determine the antioxidant activity (AC) of bioactive peptides. In this work, we investigated the AC of free and peptide Trp and Tyr residues, employing pyranine (PYR) as the probe and AAPH (2,2′-azobis(2-methylpropionamidine) dihydrochloride) as the ROO^• source. Solutions containing PYR and 10 mM AAPH were incubated at 37 °C in the absence and presence of additives. The initial consumption rates (R₀) of PYR (5 µM) were affected by the type of peptide, with free Trp showing a higher effect than short peptides (R₀ = Gly-Trp > Gly-Trp-Gly > Trp-Gly > free Trp), while the order of R₀ of Tyr residues was as follows: free Tyr ~ Tyr-Tyr-Tyr > Gly-Tyr. Experiments carried out at 1 µM PYR, and employing larger peptides showed that the AC of Trp and Tyr cannot be explained by a simple mechanism. While the generation of lag times in the kinetics would not be necessarily associated with PYR repairing, their absence would not exclusively reflect competition for ROO^•. These results demonstrate that the AC of Trp and Tyr follows complex mechanisms, implying that particular care should be taken when amino acids and peptides are proposed as antioxidants.

AAPH-cucurbit[ n ]uril systems were experimentally and theoretically studied. Radical yields formed upon photolysis of AAPH were altered by complexation with CB[8] in a stoichiometry-dependent manner, however, radical yields were not changed by CB[6].

The Lindau Nobel Laureate Meeting 2025 (LINO25) brought together more than 30 laureates and 600 young scientists in the field of chemistry from over 100 countries. One of the most remarkable contributions came from Latin America, with 24 young researchers from seven countries showcasing the high level, commitment, and diversity of science in the region. This special article documents the experience and contributions of this delegation, highlights their active role in scientific debates, their attainment of Nobel Alumni status, and their key recommendations for future generations. In addition, it provides a practical guide on the nomination process, logistical preparation, and strategies to maximize the experience during the event. Finally, it underlines the importance of increasing Latin America's visibility and strengthening its representation, including countries that have historically been underrepresented, in high-impact international scientific spaces such as Lindau.