# Towards the Development of Effective Antioxidants—The Molecular Structure and Properties—Part 2

## TL;DR

This paper reviews recent advances in understanding how antioxidant molecular structures affect their function, combining computational and experimental methods to guide better antioxidant design.

## Contribution

The paper integrates computational models with advanced synchrotron techniques to explain antioxidant mechanisms and guide formulation engineering.

## Key findings

- Polyphenolic architecture and electronic descriptors influence antioxidant activity through HAT, SET, and SPLET pathways.
- Metal coordination can stabilize antioxidants or trigger pro-oxidant effects via ligand-to-metal charge transfer.
- Computational and synchrotron methods validate antioxidant behavior and inform nanocarrier design for drug delivery.

## Abstract

The development of effective antioxidants has evolved from descriptive analysis toward a precise, mechanism-driven discipline targeting the molecular “redox switch”. This review synthesizes the critical advances reported since 2021, focusing on how the interplay between polyphenolic architecture and electronic descriptors, such as bond dissociation enthalpy and ionization potential, governs radical scavenging through the HAT, SET, and SPLET pathways. We evaluate the dual influence of metal coordination, where interactions can either enhance antioxidant stability through σ bond polarization or trigger pro-oxidant transitions via ligand-to-metal charge transfer. Central to this progress is the integration of computational models (DFT, QSAR) with advanced synchrotron methodologies (XAS, STXM, SR-FTIR, and SAXS), which provide element-specific validation of antioxidant behavior and subcellular oxidative mapping within complex matrices. Furthermore, we highlight how these molecular insights inform formulation engineering, specifically the development of organic nanocarriers and hybrid delivery systems, such as metal–phenolic networks, that shield therapeutic cargo from degradation and govern release in challenging physiological environments. These fundamental studies provide an essential physicochemical basis for medicine by enabling a better understanding and the rational design of antioxidant drugs, dietary supplements, and antioxidant strategies.